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Why are so many young people getting cancer?

News Feed
Monday, April 8, 2024

Melanie Lambrick for Vox Cancer used to be a disease of the old. Not anymore. For the past decade, doctors have been disturbed by a medical mystery: People all over the world are developing cancer at younger ages. Adults in the prime of their lives, often otherwise outwardly healthy, are dying of aggressive cancers that appear to develop more quickly and be more deadly than in the past, for reasons that scientists cannot adequately explain. Clinicians have especially been noticing a rise in cancers in the gastrointestinal (GI) system — including colorectal, kidney, and pancreatic cancers — in adults younger than 50, the cutoff for what is usually considered early-onset cancer. Scientific authorities around the world see this as one of the most pressing questions for modern medicine and are now funding an ambitious, globe-spanning research project to provide some desperately needed answers. Researchers in the US, Europe, and Asia are teaming up on a $25 million project jointly funded by the US National Cancer Institute, Cancer Research UK, Bowelbabe Fund for Cancer Research UK, and the French National Cancer Institute to investigate the leading lifestyle and environmental risk factors — from toxins to diets high in ultra-processed foods — believed to be contributing to the spike in early cancers. Over the next five years, the team will be gathering evidence on the ground in the US, Mexico, UK, France, Italy, and India. “We want to do this from an international perspective because it’s an international problem,” Andrew Chan, a cancer epidemiologist and clinical gastroenterologist at Harvard Medical School and Mass General Hospital who is co-leading the project, told me. “That helps us to get insight into what’s common across these different parts of the world and what’s unique.” Combining large population surveys, animal studies, and public health awareness campaigns, the team hopes to not only identify factors that play a role in early-onset cancers but also to establish the biological mechanisms that drive them. That could help lay the groundwork for better screenings and treatments and could ultimately have far-reaching implications for the foods we eat, the consumer goods we produce, and the very fabric of everyday life. Cancers among young adults have become a global health crisis One in five new colorectal cancer patients in the United States is under 55, according to a recent Wall Street Journal analysis of data from the National Cancer Institute. That’s nearly twice the rate in 1995. While deaths for colorectal cancer patients over 65 are going down, deaths among younger patients are increasing, a reflection of the higher mortality rates often observed in early-onset cancers. Scientists say these cancers can be more deadly because they are not caught early enough for successful interventions. (Colonoscopies are not recommended until age 45.) A decade ago, the known risk factors were largely limited to diet and exercise, as obesity was associated with a higher chance of developing colorectal and GI cancers. But we now know that it’s a lot more complicated than how much a person weighs. While the increase in global obesity rates since the mid-1990s likely plays a significant role in the uptick, scientists have found that specific diets, such as those rich in so-called ultra-processed foods, have been associated with a higher risk of GI cancers, regardless of a person’s body-mass index. Exposures to toxins in the environment and in everyday goods, including phthalates found in makeup and hair products and formaldehyde in building materials, are now also suspected to increase cancer risk in younger patients — particularly if the exposure occurred at pivotal points in a person’s life. Getting less sleep or interrupted sleep may also be a factor. “We know, for example, sleep and circadian rhythm is an important component of health,” Chan told me. “People are probably getting less sleep or having more disrupted sleep for a variety of reasons. Is that potentially changing our biology in a way that is detrimental?” Much of today’s cancer research is also focusing on the microbiome, the ecosystem — or rainforest, as one researcher put it — of bacteria that is concentrated in the gut. Certain kinds of microbiome bacteria are associated with the development of GI cancers, but researchers are still puzzling out whether those changes are a cause or a consequence of cancer. Finding solutions is crucial not only for wealthy nations, where increases in early cancer cases and deaths are most pronounced, but also for the rest of the world. Developing countries are contending with some of the same environmental contaminants as affluent countries, from microplastics to air pollution, and they are already seeing rising death rates from other obesity-related diseases. As poorer countries become more economically developed, they are also expected to see more “first world” health problems — including cancer. “This is going to be a problem that is going to be facing us as our economy gets stronger,” said Bhawna Sirohi, medical oncology director at the Balco Medical Center in Raipur, India, who is leading the project’s work in that country. It’s “facing us, the West, everywhere.” What we know — and what we don’t — about early-onset cancers The increase in early-onset cancers has become undeniable, replicated in study after study. A BMJ article published last year found that the early onset of 29 different cancers, including breast, stomach, and colorectal, had risen nearly 80 percent between 1990 and 2019 worldwide. Another study published in JAMA Network Open last August found that the occurrence of a wide range of cancers among people under 50 had increased between 2010 to 2019 among American adults, particularly among women. While colon and rectal cancers are driving much of that increase, cancers up and down the GI tract, including the bladder and kidneys, are on the rise among adults younger than 50. A 2019 Lancet paper documented an uptick in cancers among US adults 25 to 49 years old, driven by higher rates of colorectal, uterine, gallbladder, kidney, and pancreatic cancers between 1995 and 2014. Gastrointestinal cancer incidence was up 15 percent overall from 2010 to 2019, according to the JAMA study. Bile duct cancers in the passage between the liver and gallbladder (up 142 percent over the past decade) and uterine cancers (up 76 percent) have seen some of the largest increases in prevalence, the same study found, though they still occur overall less often than colon cancers. John Marshall, director of the Ruesch Center for the Cure of Gastrointestinal Cancers at Georgetown University, has been treating patients for 30 years. Early in his career, he says, he would never have a patient under the age of 50. Today, half of his patients are in that younger cohort, many of them otherwise healthy and fit. He first started to notice the trend with colorectal cancers, but later found an increase in other cancers as well, mirroring the research literature. “We’ve been observing this for more than 10 years,” Marshall told me. “The trend is continuing and increasing and being observed now in other cancers beyond colorectal.” When the spike in early cancers was first detected, scientists already knew obesity was a significant risk factor for developing cancers in the digestive tract. Groups such as the American Cancer Society targeted their recommendations around diet and exercise. Systematic reviews of the available research, though, such as one published in Frontiers in Nutrition in 2022, have identified dietary factors that are associated with a higher incidence of early-onset colorectal cancer, regardless of body weight. These include consumption of a lot of deep-fried foods, processed foods, foods high in fat, and sugary drinks and desserts, as well as low folate and fiber consumption. Marathon runners with cardboard diets, Marshall said, can be more prone to GI cancers than their physical fitness might suggest. Higher alcohol consumption is likewise associated with a higher risk of developing cancer early. Scientists also hypothesize that changes in our environment, such as the proliferation of microplastics, could be a contributing factor. From food containers to synthetic clothing, we are exposed to these tiny particles every day. They find their way into the environment and, when we inadvertently eat or drink them, into our bodies and our GI tracts. According to a paper published last year by a New Zealand research team, the upticks in cancers among young adults matched the timeline that we would expect from the multiplication of microplastics in the environment. Research on cellular and rodent models has suggested that microplastics could promote tumor growth. Though more research is needed, we already know these materials contain chemicals that can disrupt hormones and pose a risk to our health. These findings also point to another revelation: “We have, each of us, different risk depending on when we are born,” Shuji Ogino, a molecular pathological epidemiologist at Harvard Medical School, told me. People born in the first half of the 20th century had a lower risk of developing cancer by age 50 than people born in the second half, Ogino said. That would support the idea that environmental changes and society-wide alterations to our diet and food production may be contributing to the increase in early-onset cancers. In the same vein, scientists increasingly suspect that exposures to risk factors at certain ages — whether in utero, early childhood, or early adulthood. — could be playing an important role in a person’s risk of developing cancer at a young age. Preliminary findings, such as a study that found consuming more sugary drinks while in adolescence was associated with a higher risk of developing colorectal cancer early in women, lend support to those theories. The next frontiers in understanding the increase in early-onset cancers A definitive explanation for these increases in cancer rates among younger adults continues to elude scientists. They have a lot of theories and some evidence to support them, but scientific progress moves slowly. We know more than we did a decade ago, but we are still a long way from a clear answer. “The reality is, we don’t know,” Marshall said. The new research project led by Chan and Yin Cao of Washington University in St. Louis, the recipient of the $25 million Cancer Grand Challenges award, represents one of the most comprehensive attempts to find clearer answers. “Are the things that we’re seeing truly causes or are they just bystanders of some of these associations?” Chan said. “We need to really understand what the true causes are. That will be difficult just relying on observational data in humans. We have the opportunity to experimentally model between the human and animal studies.” Some of the researchers will collect population cohort data in the US, UK, Europe, and Mexico and ask participants about known cancer risk factors, such as their diet and lifestyle, as well as novel factors, such as environmental exposures and demographic characteristics. They will also collect stool samples to analyze the participants’ microbiomes to identify any links between changes in gut bacteria and cancer growth. The information gathered from those studies will be used to generate hypotheses for animal and in vitro experiments. Scientists will test different potential carcinogens in different combinations and simulate exposure at different stages of the life cycle (including in utero and in adolescence). With this multifaceted approach, the team will be able to test many of the leading hypotheses for the increase in early-onset cancers that need stronger evidence. The data on the carcinogenic potential of microplastics, for example, has been so far limited mostly to short-term studies on mice. The researchers acknowledge their project won’t definitively answer every question about early-onset cancer. But their wide-ranging approach to an extraordinarily complex subject could start to bring more clarity. “Even if we may not get 100 percent or even if we only answer 20 percent of the picture, we hope this mechanism, the paradigm in terms of integrating human and animal studies, is going to be the one that will lead to more and more future investigations,” Cao told me. “I think that would be a huge impact on the field.” The trial will also compare cancer prevention and treatment interventions in diverse settings, from urban London to rural villages in India. As part of Sirohi’s contribution to the project, researchers will take a randomized approach to educating Indian villagers on colorectal cancer risk (she says many of her patients don’t know the symptoms to look for), encouraging them to submit a stool sample, and follow up with a colonoscopy if there are signs of bleeding. Wherever these inquiries lead may eventually force us to rethink many dimensions of modern life. “What does a truly balanced diet look like? How do you feed your microbiome and culture your rainforest?” Marshall said. “The hope is we will learn a lot from this.” The answers may beget more questions. How do we feed a world of 8 billion people a diet that lowers the risk of more people dying too young? Few scientific questions are more urgent right now.

An illustration of a man in a shower, looking down at a giant question mark on his abdomen.
Melanie Lambrick for Vox

Cancer used to be a disease of the old. Not anymore.

For the past decade, doctors have been disturbed by a medical mystery: People all over the world are developing cancer at younger ages.

Adults in the prime of their lives, often otherwise outwardly healthy, are dying of aggressive cancers that appear to develop more quickly and be more deadly than in the past, for reasons that scientists cannot adequately explain.

Clinicians have especially been noticing a rise in cancers in the gastrointestinal (GI) system — including colorectal, kidney, and pancreatic cancers — in adults younger than 50, the cutoff for what is usually considered early-onset cancer.

Scientific authorities around the world see this as one of the most pressing questions for modern medicine and are now funding an ambitious, globe-spanning research project to provide some desperately needed answers.

Researchers in the US, Europe, and Asia are teaming up on a $25 million project jointly funded by the US National Cancer Institute, Cancer Research UK, Bowelbabe Fund for Cancer Research UK, and the French National Cancer Institute to investigate the leading lifestyle and environmental risk factors — from toxins to diets high in ultra-processed foods — believed to be contributing to the spike in early cancers. Over the next five years, the team will be gathering evidence on the ground in the US, Mexico, UK, France, Italy, and India.

“We want to do this from an international perspective because it’s an international problem,” Andrew Chan, a cancer epidemiologist and clinical gastroenterologist at Harvard Medical School and Mass General Hospital who is co-leading the project, told me. “That helps us to get insight into what’s common across these different parts of the world and what’s unique.”

Combining large population surveys, animal studies, and public health awareness campaigns, the team hopes to not only identify factors that play a role in early-onset cancers but also to establish the biological mechanisms that drive them. That could help lay the groundwork for better screenings and treatments and could ultimately have far-reaching implications for the foods we eat, the consumer goods we produce, and the very fabric of everyday life.

Cancers among young adults have become a global health crisis

One in five new colorectal cancer patients in the United States is under 55, according to a recent Wall Street Journal analysis of data from the National Cancer Institute. That’s nearly twice the rate in 1995.

While deaths for colorectal cancer patients over 65 are going down, deaths among younger patients are increasing, a reflection of the higher mortality rates often observed in early-onset cancers. Scientists say these cancers can be more deadly because they are not caught early enough for successful interventions. (Colonoscopies are not recommended until age 45.)

A decade ago, the known risk factors were largely limited to diet and exercise, as obesity was associated with a higher chance of developing colorectal and GI cancers. But we now know that it’s a lot more complicated than how much a person weighs.

While the increase in global obesity rates since the mid-1990s likely plays a significant role in the uptick, scientists have found that specific diets, such as those rich in so-called ultra-processed foods, have been associated with a higher risk of GI cancers, regardless of a person’s body-mass index.

Exposures to toxins in the environment and in everyday goods, including phthalates found in makeup and hair products and formaldehyde in building materials, are now also suspected to increase cancer risk in younger patients — particularly if the exposure occurred at pivotal points in a person’s life. Getting less sleep or interrupted sleep may also be a factor.

“We know, for example, sleep and circadian rhythm is an important component of health,” Chan told me. “People are probably getting less sleep or having more disrupted sleep for a variety of reasons. Is that potentially changing our biology in a way that is detrimental?”

Much of today’s cancer research is also focusing on the microbiome, the ecosystem — or rainforest, as one researcher put it — of bacteria that is concentrated in the gut. Certain kinds of microbiome bacteria are associated with the development of GI cancers, but researchers are still puzzling out whether those changes are a cause or a consequence of cancer.

Finding solutions is crucial not only for wealthy nations, where increases in early cancer cases and deaths are most pronounced, but also for the rest of the world. Developing countries are contending with some of the same environmental contaminants as affluent countries, from microplastics to air pollution, and they are already seeing rising death rates from other obesity-related diseases. As poorer countries become more economically developed, they are also expected to see more “first world” health problems — including cancer.

“This is going to be a problem that is going to be facing us as our economy gets stronger,” said Bhawna Sirohi, medical oncology director at the Balco Medical Center in Raipur, India, who is leading the project’s work in that country. It’s “facing us, the West, everywhere.”

What we know — and what we don’t — about early-onset cancers

The increase in early-onset cancers has become undeniable, replicated in study after study. A BMJ article published last year found that the early onset of 29 different cancers, including breast, stomach, and colorectal, had risen nearly 80 percent between 1990 and 2019 worldwide. Another study published in JAMA Network Open last August found that the occurrence of a wide range of cancers among people under 50 had increased between 2010 to 2019 among American adults, particularly among women.

While colon and rectal cancers are driving much of that increase, cancers up and down the GI tract, including the bladder and kidneys, are on the rise among adults younger than 50. A 2019 Lancet paper documented an uptick in cancers among US adults 25 to 49 years old, driven by higher rates of colorectal, uterine, gallbladder, kidney, and pancreatic cancers between 1995 and 2014. Gastrointestinal cancer incidence was up 15 percent overall from 2010 to 2019, according to the JAMA study. Bile duct cancers in the passage between the liver and gallbladder (up 142 percent over the past decade) and uterine cancers (up 76 percent) have seen some of the largest increases in prevalence, the same study found, though they still occur overall less often than colon cancers.

John Marshall, director of the Ruesch Center for the Cure of Gastrointestinal Cancers at Georgetown University, has been treating patients for 30 years. Early in his career, he says, he would never have a patient under the age of 50. Today, half of his patients are in that younger cohort, many of them otherwise healthy and fit. He first started to notice the trend with colorectal cancers, but later found an increase in other cancers as well, mirroring the research literature.

“We’ve been observing this for more than 10 years,” Marshall told me. “The trend is continuing and increasing and being observed now in other cancers beyond colorectal.”

When the spike in early cancers was first detected, scientists already knew obesity was a significant risk factor for developing cancers in the digestive tract. Groups such as the American Cancer Society targeted their recommendations around diet and exercise.

Systematic reviews of the available research, though, such as one published in Frontiers in Nutrition in 2022, have identified dietary factors that are associated with a higher incidence of early-onset colorectal cancer, regardless of body weight. These include consumption of a lot of deep-fried foods, processed foods, foods high in fat, and sugary drinks and desserts, as well as low folate and fiber consumption.

Marathon runners with cardboard diets, Marshall said, can be more prone to GI cancers than their physical fitness might suggest. Higher alcohol consumption is likewise associated with a higher risk of developing cancer early.

Scientists also hypothesize that changes in our environment, such as the proliferation of microplastics, could be a contributing factor. From food containers to synthetic clothing, we are exposed to these tiny particles every day. They find their way into the environment and, when we inadvertently eat or drink them, into our bodies and our GI tracts.

According to a paper published last year by a New Zealand research team, the upticks in cancers among young adults matched the timeline that we would expect from the multiplication of microplastics in the environment. Research on cellular and rodent models has suggested that microplastics could promote tumor growth. Though more research is needed, we already know these materials contain chemicals that can disrupt hormones and pose a risk to our health.

These findings also point to another revelation: “We have, each of us, different risk depending on when we are born,” Shuji Ogino, a molecular pathological epidemiologist at Harvard Medical School, told me.

People born in the first half of the 20th century had a lower risk of developing cancer by age 50 than people born in the second half, Ogino said. That would support the idea that environmental changes and society-wide alterations to our diet and food production may be contributing to the increase in early-onset cancers.

In the same vein, scientists increasingly suspect that exposures to risk factors at certain ages — whether in utero, early childhood, or early adulthood. — could be playing an important role in a person’s risk of developing cancer at a young age. Preliminary findings, such as a study that found consuming more sugary drinks while in adolescence was associated with a higher risk of developing colorectal cancer early in women, lend support to those theories.

The next frontiers in understanding the increase in early-onset cancers

A definitive explanation for these increases in cancer rates among younger adults continues to elude scientists. They have a lot of theories and some evidence to support them, but scientific progress moves slowly. We know more than we did a decade ago, but we are still a long way from a clear answer.

“The reality is, we don’t know,” Marshall said.

The new research project led by Chan and Yin Cao of Washington University in St. Louis, the recipient of the $25 million Cancer Grand Challenges award, represents one of the most comprehensive attempts to find clearer answers.

“Are the things that we’re seeing truly causes or are they just bystanders of some of these associations?” Chan said. “We need to really understand what the true causes are. That will be difficult just relying on observational data in humans. We have the opportunity to experimentally model between the human and animal studies.”

Some of the researchers will collect population cohort data in the US, UK, Europe, and Mexico and ask participants about known cancer risk factors, such as their diet and lifestyle, as well as novel factors, such as environmental exposures and demographic characteristics. They will also collect stool samples to analyze the participants’ microbiomes to identify any links between changes in gut bacteria and cancer growth.

The information gathered from those studies will be used to generate hypotheses for animal and in vitro experiments. Scientists will test different potential carcinogens in different combinations and simulate exposure at different stages of the life cycle (including in utero and in adolescence).

With this multifaceted approach, the team will be able to test many of the leading hypotheses for the increase in early-onset cancers that need stronger evidence. The data on the carcinogenic potential of microplastics, for example, has been so far limited mostly to short-term studies on mice.

The researchers acknowledge their project won’t definitively answer every question about early-onset cancer. But their wide-ranging approach to an extraordinarily complex subject could start to bring more clarity.

“Even if we may not get 100 percent or even if we only answer 20 percent of the picture, we hope this mechanism, the paradigm in terms of integrating human and animal studies, is going to be the one that will lead to more and more future investigations,” Cao told me. “I think that would be a huge impact on the field.”

The trial will also compare cancer prevention and treatment interventions in diverse settings, from urban London to rural villages in India. As part of Sirohi’s contribution to the project, researchers will take a randomized approach to educating Indian villagers on colorectal cancer risk (she says many of her patients don’t know the symptoms to look for), encouraging them to submit a stool sample, and follow up with a colonoscopy if there are signs of bleeding.

Wherever these inquiries lead may eventually force us to rethink many dimensions of modern life.

“What does a truly balanced diet look like? How do you feed your microbiome and culture your rainforest?” Marshall said. “The hope is we will learn a lot from this.”

The answers may beget more questions. How do we feed a world of 8 billion people a diet that lowers the risk of more people dying too young?

Few scientific questions are more urgent right now.

Read the full story here.
Photos courtesy of

Giant Sloths and Many Other Massive Creatures Were Once Common on Our Planet. With Environmental Changes, Such Giants Could Thrive Again

If large creatures like elephants, giraffes and bison are allowed to thrive, they could alter habitats that allow for the rise of other giants

Giant Sloths and Many Other Massive Creatures Were Once Common on Our Planet. With Environmental Changes, Such Giants Could Thrive Again If large creatures like elephants, giraffes and bison are allowed to thrive, they could alter habitats that allow for the rise of other giants Riley Black - Science Correspondent July 11, 2025 8:00 a.m. Ancient sloths lived in trees, on mountains, in deserts, in boreal forests and on open savannas. Some grew as large as elephants. Illustration by Diego Barletta The largest sloth of all time was the size of an elephant. Known to paleontologists as Eremotherium, the shaggy giant shuffled across the woodlands of the ancient Americas between 60,000 and five million years ago. Paleontologists have spent decades hotly debating why such magnificent beasts went extinct, the emerging picture involving a one-two punch of increasing human influence on the landscape and a warmer interglacial climate that began to change the world’s ecosystems. But even less understood is how our planet came to host entire communities of such immense animals during the Pleistocene. Now, a new study on the success of the sloths helps to reveal how the world of Ice Age giants came to be, and hints that an Earth brimming with enormous animals could come again. Florida Museum of Natural History paleontologist Rachel Narducci and colleagues tracked how sloths came to be such widespread and essential parts of the Pleistocene Americas and published their findings in Science this May. The researchers found that climate shifts that underwrote the spread of grasslands allowed big sloths to arise, the shaggy mammals then altering those habitats to maintain open spaces best suited to big bodies capable of moving long distances. The interactions between the animals and environment show how giants attained their massive size, and how strange it is that now our planet has fewer big animals than would otherwise be here. Earth still boasts some impressively big species. In fact, the largest animal of all time is alive right now and only evolved relatively recently. The earliest blue whale fossils date to about 1.5 million years ago, and, at 98 feet long and more than 200 tons, the whale is larger than any mammoth or dinosaur. Our planet has always boasted a greater array of small species than large ones, even during prehistoric ages thought of as synonymous with megafauna. Nevertheless, Earth’s ecosystems are still in a megafaunal lull that began at the close of the Ice Age. “I often say we are living on a downsized planet Earth,” says University of Maine paleoecologist Jacquelyn Gill.Consider what North America was like during the Pleistocene, between 11,000 years and two million ago. The landmass used to host multiple forms of mammoths, mastodons, giant ground sloths, enormous armadillos, multiple species of sabercat, huge bison, dire wolves and many more large creatures that formed ancient ecosystems unlike anything on our planet today. In addition, many familiar species such as jaguars, black bears, coyotes, white-tailed deer and golden eagles also thrived. Elsewhere in the world lived terror birds taller than an adult human, wombats the size of cars, woolly rhinos, a variety of elephants with unusual tusks and other creatures. Ecosystems capable of supporting such giants have been the norm rather than the exception for tens of millions of years. Giant sloths were among the greatest success stories among the giant-size menagerie. The herbivores evolved on South America when it was still an island continent, only moving into Central and North America as prehistoric Panama connected the landmasses about 2.7 million years ago. Some were small, like living two- and three-toed sloths, while others embodied a range of sizes all the way up to elephant-sized giants like Eremotherium and the “giant beast” Megatherium. An Eremotherium skeleton at the Houston Museum of Natural Science demonstrates just how large the creature grew. James Nielsen / Houston Chronicle via Getty Images The earliest sloths originated on South America about 35 million years ago. They were already big. Narducci and colleagues estimate that the common ancestor of all sloths was between about 150 and 770 pounds—or similar to the range of sizes seen among black bears today—and they walked on the ground. “I was surprised and thrilled” to find that sloths started off large, Narducci says, as ancestral forms of major mammal groups are often small, nocturnal creatures. The earliest sloths were already in a good position to shift with Earth’s climate and ecological changes. The uplift of the Andes Mountains in South America led to changes on the continent as more open, drier grasslands spread where there had previously been wetter woodlands and forests. While some sloths became smaller as they spent more time around and within trees, the grasslands would host the broadest diversity of sloth species. The grasslands sloths were the ones that ballooned to exceptional sizes. Earth has been shifting between warmer and wetter times, like now, and cooler and drier climates over millions of years. The chillier and more arid times are what gave sloths their size boost. During these colder spans, bigger sloths were better able to hold on to their body heat, but they also didn’t need as much water, and they were capable of traveling long distances more efficiently thanks to their size. “The cooler and drier the climate, especially after 11.6 million years ago, led to expansive grasslands, which tends to favor the evolution of increasing body mass,” Narducci says. The combination of climate shifts, mountain uplift and vegetation changes created environments where sloths could evolve into a variety of forms—including multiple times when sloths became giants again. Gill says that large body size was a “winning strategy” for herbivores. “At a certain point, megaherbivores get so large that most predators can’t touch them; they’re able to access nutrition in foods that other animals can’t really even digest thanks to gut microbes that help them digest cellulose, and being large means you’re also mobile,” Gill adds, underscoring advantages that have repeatedly pushed animals to get big time and again. The same advantages underwrote the rise of the biggest dinosaurs as well as more recent giants like the sloths and mastodons. As large sloths could travel further, suitable grassland habitats stretched from Central America to prehistoric Florida. “This is what also allowed for their passage into North America,” Narducci says. Sloths were able to follow their favored habitats between continents. If the world were to shift back toward cooler and drier conditions that assisted the spread of the grasslands that gave sloths their size boost, perhaps similar giants could evolve. The sticking point is what humans are doing to Earth’s climate, ecosystems and existing species. The diversity and number of large species alive today is vastly, and often negatively, affected by humans. A 2019 study of human influences on 362 megafauna species, on land and in the water, found that 70 percent are diminishing in number, and 59 percent are getting dangerously close to extinction. But if that relationship were to change, either through our actions or intentions, studies like the new paper on giant sloths hint that ecosystems brimming with a wealth of megafaunal species could evolve again. Big animals change the habitats where they live, which in turn tends to support more large species adapted to those environments. The giant sloths that evolved among ancient grasslands helped to keep those spaces open in tandem with other big herbivores, such as mastodons, as well as the large carnivores that preyed upon them. Paleontologists and ecologists know this from studies of how large animals such as giraffes and rhinos affect vegetation around them. Big herbivores, in particular, tend to keep habitats relatively open. Elephants and other big beasts push over trees, trample vegetation underfoot, eat vast amounts of greenery and transport seeds in their dung, disassembling vegetation while unintentionally planting the beginnings of new habitats. Such broad, open spaces were essential to the origins of the giant sloths, and so creating wide-open spaces helps spur the evolution of giants to roam such environments. For now, we are left with the fossil record of giant animals that were here so recently that some of their bones aren’t even petrified, skin and fur still clinging to some skeletons. “The grasslands they left behind are just not the same, in ways we’re really only starting to understand and appreciate,” Gill says. A 2019 study on prehistoric herbivores in Africa, for example, found that the large plant-eaters altered the water cycling, incidence of fire and vegetation of their environment in a way that has no modern equivalent and can’t just be assumed to be an ancient version of today’s savannas. The few megaherbivores still with us alter the plant life, water flow, seed dispersal and other aspects of modern environments in their own unique ways, she notes, which should be a warning to us to protect them—and the ways in which they affect our planet. If humans wish to see the origin of new magnificent giants like the ones we visit museums to see, we must change our relationship to the Earth first. Get the latest Science stories in your inbox.

How changes in California culture have influenced the evolution of wild animals in Los Angeles

A new study argues that religion, politics and war affect how animals and plants in cities evolve, and the confluence of these forces seem to be actively affecting urban wildlife in L.A.

For decades, biologists have studied how cities affect wildlife by altering food supplies, fragmenting habitats and polluting the environment. But a new global study argues that these physical factors are only part of the story. Societal factors, the researchers claim, especially those tied to religion, politics and war, also leave lasting marks on the evolutionary paths of the animals and plants that share our cities.Published in Nature Cities, the comprehensive review synthesizes evidence from cities worldwide, revealing how human conflict and cultural practices affect wildlife genetics, behavior and survival in urban environments.The paper challenges the tendency to treat the social world as separate from ecological processes. Instead, the study argues, we should consider the ways the aftershocks of religious traditions, political systems and armed conflicts can influence the genetic structure of urban wildlife populations. (Gabriella Angotti-Jones / Los Angeles Times) “Social sciences have been very far removed from life sciences for a very long time, and they haven’t been integrated,” said Elizabeth Carlen, a biologist at Washington University in St. Louis and co-lead author of the study. “We started just kind of playing around with what social and cultural processes haven’t been talked about,” eventually focusing on religion, politics and war because of their persistent yet underexamined impacts on evolutionary biology, particularly in cities, where cultural values and built environments are densely concentrated.Carlen’s own work in St. Louis examines how racial segregation and urban design, often influenced by policing strategies, affect ecological conditions and wild animals’ access to green spaces.“Crime prevention through environmental design,” she said, is one example of how these factors influence urban wildlife. “Law enforcement can request that there not be bushes … or short trees, because then they don’t have a sight line across the park.” Although that design choice may serve surveillance goals, it also limits the ability of small animals to navigate those spaces.These patterns, she emphasized, aren’t unique to St. Louis. “I’m positive that it’s happening in Los Angeles. Parks in Beverly Hills are going to look very different than parks in Compton. And part of that is based on what policing looks like in those different places.” This may very well be the case, as there is a significantly lower level of urban tree species richness in areas like Compton than in areas like Beverly Hills, according to UCLA’s Biodiversity Atlas. A coyote wanders onto the fairway, with the sprinklers turned on, as a golfer makes his way back to his cart after hitting a shot on the 16th hole of the Harding golf course at Griffith Park. (Mel Melcon / Los Angeles Times) The study also examines war and its disruptions, which can have unpredictable effects on animal populations. Human evacuation from war zones can open urban habitats to wildlife, while the destruction of green spaces or contamination of soil and water can fragment ecosystems and reduce genetic diversity.In Kharkiv, Ukraine, for example, human displacement during the Russian invasion led to the return of wild boars and deer to urban parks, according to the study. In contrast, sparrows, which depend on human food waste, nearly vanished from high-rise areas.All of this, the researchers argue, underscores the need to rethink how cities are designed and managed by recognizing how religion, politics and war shape not just human communities but also the evolutionary trajectories of urban wildlife. By integrating ecological and social considerations into urban development, planners and scientists can help create cities that are more livable for people while also supporting the long-term genetic diversity and adaptability of the other species that inhabit them.This intersection of culture and biology may be playing out in cities across the globe, including Los Angeles.A study released earlier this year tracking coyotes across L.A. County found that the animals were more likely to avoid wealthier neighborhoods, not because of a lack of access or food scarcity, but possibly due to more aggressive human behavior toward them and higher rates of “removal” — including trapping and releasing elsewhere, and in some rare cases, killing them. In lower-income areas, where trapping is less common, coyotes tended to roam more freely, even though these neighborhoods often had more pollution and fewer resources that would typically support wild canines. Researchers say these patterns reflect how broader urban inequities are written directly into the movements of and risks faced by wildlife in the city.Black bears, parrots and even peacocks tell a similar story in Los Angeles. Wilson Sherman, a PhD student at UCLA who is studying human-black bear interactions, highlights how local politics and fragmented municipal governance shape not only how animals are managed but also where they appear. (Carolyn Cole / Los Angeles Times) “Sierra Madre has an ordinance requiring everyone to have bear-resistant trash cans,” Sherman noted. “Neighboring Arcadia doesn’t.” This kind of patchwork governance, Sherman said, can influence where wild animals ultimately spend their time, creating a mosaic of risk and opportunity for species whose ranges extend across multiple jurisdictions.Cultural values also play a role. Thriving populations of non-native birds, such as Amazon parrots and peacocks, illustrate how aesthetic preferences and everyday choices can significantly influence the city’s ecological makeup in lasting ways.Sherman also pointed to subtler, often overlooked influences, such as policing and surveillance infrastructure. Ideally, the California Department of Fish and Wildlife would be the first agency to respond in a “wildlife situation,” as Sherman put it. But, he said, what often ends up happening is that people default to calling the police, especially when the circumstances involve animals that some urban-dwelling humans may find threatening, like bears.Police departments typically do not possess the same expertise and ability as CDFW to manage and then relocate bears. If a bear poses a threat to human life, police policy is to kill the bear. However, protocols for responding to wildlife conflicts that are not life-threatening can vary from one community to another. And how police use non-lethal methods of deterrence — such as rubber bullets and loud noises — can shape bear behavior.Meanwhile, the growing prevalence of security cameras and motion-triggered alerts has provided residents with new forms of visibility into urban biodiversity. “That might mean that people are suddenly aware that a coyote is using their yard,” Sherman said. In turn, that could trigger a homeowner to purposefully rework the landscape of their property so as to discourage coyotes from using it. Surveillance systems, he said, are quietly reshaping both public perception and policy around who belongs in the city, and who doesn’t. A mountain lion sits in a tree after being tranquilized along San Vicente Boulevard in Brentwood on Oct. 27, 2022. (Wally Skalij / Los Angeles Times) Korinna Domingo, founder and director of the Cougar Conservancy, emphasized how cougar behavior in Los Angeles is similarly shaped by decades of urban development, fragmented landscapes and the social and political choices that structure them. “Policies like freeway construction, zoning and even how communities have been historically policed or funded can affect where and how cougars move throughout L.A.,” she said. For example, these forces have prompted cougars to adapt by becoming more nocturnal, using culverts or taking riskier crossings across fragmented landscapes.Urban planning and evolutionary consequences are deeply intertwined, Domingo says. For example, mountain lion populations in the Santa Monica and Santa Ana mountains have shown signs of reduced genetic diversity due to inbreeding, an issue created not by natural processes, but by political and planning decisions — such as freeway construction and zoning decisions— that restricted their movement decades ago.Today, the Wallis Annenberg Wildlife Crossing, is an attempt to rectify that. The massive infrastructure project is happening only, Domingo said, “because of community, scientific and political will all being aligned.”However, infrastructure alone isn’t enough. “You can have habitat connectivity all you want,” she said, but you also have to think about social tolerance. Urban planning that allows for animal movement also increases the likelihood of contact with people, pets and livestock — which means humans need to learn how to interact with wild animals in a healthier way.In L.A., coexistence strategies can look very different depending on the resources, ordinances and attitudes of each community. Although wealthier residents may have the means to build predator-proof enclosures, others lack the financial or institutional support to do the same. And some with the means simply choose not to, instead demanding lethal removal., “Wildlife management is not just about biology,” Domingo said. “It’s about values, power, and really, who’s at the table.”Wildlife management in the United States has long been informed by dominant cultural and religious worldviews, particularly those grounded in notions of human exceptionalism and control over nature. Carlen, Sherman and Domingo all brought up how these values shaped early policies that framed predators as threats to be removed rather than species to be understood or respected. In California, this worldview contributed not only to the widespread killing of wolves, bears and cougars but also to the displacement of American Indian communities whose land-based practices and beliefs conflicted with these approaches. A male peacock makes its way past Ian Choi, 21 months old, standing in front of his home on Altura Road in Arcadia. (Mel Melcon / Los Angeles Times) Wildlife management in California, specifically, has long been shaped by these same forces of violence, originating in bounty campaigns not just against predators like cougars and wolves but also against American Indian peoples. These intertwined legacies of removal, extermination and land seizure continue to influence how certain animals and communities are perceived and treated today.For Alan Salazar, a tribal elder with the Fernandeño Tataviam Band of Mission Indians, those legacies run deep. “What happened to native peoples happened to our large predators in California,” he said. “Happened to our plant relatives.” Reflecting on the genocide of Indigenous Californians and the coordinated extermination of grizzly bears, wolves and mountain lions, Salazar sees a clear parallel.“There were three parts to our world — the humans, the animals and the plants,” he explained. “We were all connected. We respected all of them.” Salazar explains that his people’s relationship with the land, animals and plants is itself a form of religion, one grounded in ceremony, reciprocity and deep respect. Salazar said his ancestors lived in harmony with mountain lions for over 10,000 years, not by eliminating them but by learning from them. Other predators — cougars, bears, coyotes and wolves — were also considered teachers, honored through ceremony and studied for their power and intelligence. “Maybe we had a better plan on how to live with mountain lions, wolves and bears,” he said. “Maybe you should look at tribal knowledge.”He views the Wallis Annenberg Wildlife Crossing — for which he is a Native American consultant — as a cultural opportunity. “It’s not just for mountain lions,” he said. “It’s for all animals. And that’s why I wanted to be involved.” He believes the project has already helped raise awareness and shift perceptions about coexistence and planning, and hopes that it will help native plants, animals and peoples.As L.A. continues to grapple with the future of wildlife in its neighborhoods, canyons and corridors, Salazar and others argue that it is an opportunity to rethink the cultural frameworks, governance systems and historical injustices that have long shaped human-animal relations in the city. Whether through policy reform, neighborhood education or sacred ceremony, residents need reminders that evolutionary futures are being shaped not only in forests and preserves but right here, across freeways, backyards and local council meetings. The Wallis Annenberg Wildlife Crossing under construction over the 101 Freeway near Liberty Canyon Road in Agoura Hills on July 12, 2024. (Myung J. Chun / Los Angeles Times) The research makes clear that wildlife is not simply adapting to urban environments in isolation; it is adapting to a range of factors, including policing, architecture and neighborhood design. Carlen believes this opens a crucial frontier for interdisciplinary research, especially in cities like Los Angeles, where uneven geographies, biodiversity and political decisions intersect daily. “I think there’s a lot of injustice in cities that are happening to both humans and wildlife,” she said. “And I think the potential is out there for justice to be brought to both of those things.”

Something Strange Is Happening to Tomatoes Growing on the Galápagos Islands

Scientists say wild tomato plants on the archipelago's western islands are experiencing "reverse evolution" and reverting back to ancestral traits

Something Strange Is Happening to Tomatoes Growing on the Galápagos Islands Scientists say wild tomato plants on the archipelago’s western islands are experiencing “reverse evolution” and reverting back to ancestral traits Sarah Kuta - Daily Correspondent July 9, 2025 4:29 p.m. Scientists are investigating the production of ancestral alkaloids by tomatoes in the Galápagos Islands. Adam Jozwiak / University of California, Riverside Some tomatoes growing on the Galápagos Islands appear to be going back in time by producing the same toxins their ancestors did millions of years ago. Scientists describe this development—a controversial process known as “reverse evolution”—in a June 18 paper published in the journal Nature Communications. Tomatoes are nightshades, a group of plants that also includes eggplants, potatoes and peppers. Nightshades, also known as Solanaceae, produce bitter compounds called alkaloids, which help fend off hungry bugs, animals and fungi. When plants produce alkaloids in high concentrations, they can sicken the humans who eat them. To better understand alkaloid synthesis, researchers traveled to the Galápagos Islands, the volcanic chain roughly 600 miles off the coast of mainland Ecuador made famous by British naturalist Charles Darwin. They gathered and studied more than 30 wild tomato plants growing in different places on various islands. The Galápagos tomatoes are the descendents of plants from South America that were probably carried to the archipelago by birds. The team’s analyses revealed that the tomatoes growing on the eastern islands were behaving as expected, by producing alkaloids that are similar to those found in modern, cultivated varieties. But those growing on the western islands, they found, were creating alkaloids that were more closely related to those produced by eggplants millions of years ago. Tomatoes growing on the western islands (shown here) are producing ancestral alkaloids.  Adam Jozwiak / University of California, Riverside Researchers suspect the environment may be responsible for the plants’ unexpected return to ancestral alkaloids. The western islands are much younger than the eastern islands, so the soil is less developed and the landscape is more barren. To survive in these harsh conditions, perhaps it was advantageous for the tomato plants to revert back to older alkaloids, the researchers posit. “The plants may be responding to an environment that more closely resembles what their ancestors faced,” says lead author Adam Jozwiak, a biochemist at the University of California, Riverside, to BBC Wildlife’s Beki Hooper. However, for now, this is just a theory. Scientists say they need to conduct more research to understand why tomato plants on the western islands have adapted this way. Scientists were able to uncover the underlying molecular mechanisms at play: Four amino acids in a single enzyme appear to be responsible for the reversion back to the ancestral alkaloids, they found. They also used evolutionary modeling to confirm the direction of the adaptation—that is, that the tomatoes on the western islands had indeed returned to an earlier, ancestral state. Among evolutionary biologists, “reverse evolution” is somewhat contentious. The commonly held belief is that evolution marches forward, not backward. It’s also difficult to prove an organism has reverted back to an older trait through the same genetic pathways. But, with the new study, researchers say they’ve done exactly that. “Some people don’t believe in this,” says Jozwiak in a statement. “But the genetic and chemical evidence points to a return to an ancestral state. The mechanism is there. It happened.” So, if “reverse evolution” happened in wild tomatoes, could something similar happen in humans? In theory, yes, but it would take a long time, Jozwiak says. “If environmental conditions shifted dramatically over long timescales, it’s possible that traits from our distant past could re-emerge, but whether that ever happens is highly uncertain,” Jozwiak tells Newsweek’s Daniella Gray. “It’s speculative and would take millions of years, if at all.” Get the latest stories in your inbox every weekday.

Lifesize herd of puppet animals begins climate action journey from Africa to Arctic Circle

The Herds project from the team behind Little Amal will travel 20,000km taking its message on environmental crisis across the worldHundreds of life-size animal puppets have begun a 20,000km (12,400 mile) journey from central Africa to the Arctic Circle as part of an ambitious project created by the team behind Little Amal, the giant puppet of a Syrian girl that travelled across the world.The public art initiative called The Herds, which has already visited Kinshasa and Lagos, will travel to 20 cities over four months to raise awareness of the climate crisis. Continue reading...

Hundreds of life-size animal puppets have begun a 20,000km (12,400 mile) journey from central Africa to the Arctic Circle as part of an ambitious project created by the team behind Little Amal, the giant puppet of a Syrian girl that travelled across the world.The public art initiative called The Herds, which has already visited Kinshasa and Lagos, will travel to 20 cities over four months to raise awareness of the climate crisis.It is the second major project from The Walk Productions, which introduced Little Amal, a 12-foot puppet, to the world in Gaziantep, near the Turkey-Syria border, in 2021. The award-winning project, co-founded by the Palestinian playwright and director Amir Nizar Zuabi, reached 2 million people in 17 countries as she travelled from Turkey to the UK.The Herds’ journey began in Kinshasa’s Botanical Gardens on 10 April, kicking off four days of events. It moved on to Lagos, Nigeria, the following week, where up to 5,000 people attended events performed by more than 60 puppeteers.On Friday the streets of Dakar in Senegal will be filled with more than 40 puppet zebras, wildebeest, monkeys, giraffes and baboons as they run through Médina, one of the busiest neighbourhoods, where they will encounter a creation by Fabrice Monteiro, a Belgium-born artist who lives in Senegal, and is known for his large-scale sculptures. On Saturday the puppets will be part of an event in the fishing village of Ngor.The Herds’ 20,000km journey began in Kinshasa, the Democratic Republic of the Congo. Photograph: Berclaire/walk productionsThe first set of animal puppets was created by Ukwanda Puppetry and Designs Art Collective in Cape Town using recycled materials, but in each location local volunteers are taught how to make their own animals using prototypes provided by Ukwanda. The project has already attracted huge interest from people keen to get involved. In Dakar more than 300 artists applied for 80 roles as artists and puppet guides. About 2,000 people will be trained to make the puppets over the duration of the project.“The idea is that we’re migrating with an ever-evolving, growing group of animals,” Zuabi told the Guardian last year.Zuabi has spoken of The Herds as a continuation of Little Amal’s journey, which was inspired by refugees, who often cite climate disaster as a trigger for forced migration. The Herds will put the environmental emergency centre stage, and will encourage communities to launch their own events to discuss the significance of the project and get involved in climate activism.The puppets are created with recycled materials and local volunteers are taught how to make them in each location. Photograph: Ant Strack“The idea is to put in front of people that there is an emergency – not with scientific facts, but with emotions,” said The Herds’ Senegal producer, Sarah Desbois.She expects thousands of people to view the four events being staged over the weekend. “We don’t have a tradition of puppetry in Senegal. As soon as the project started, when people were shown pictures of the puppets, they were going crazy.”Little Amal, the puppet of a Syrian girl that has become a symbol of human rights, in Santiago, Chile on 3 January. Photograph: Anadolu/Getty ImagesGrowing as it moves, The Herds will make its way from Dakar to Morocco, then into Europe, including London and Paris, arriving in the Arctic Circle in early August.

Dead, sick pelicans turning up along Oregon coast

So far, no signs of bird flu but wildlife officials continue to test the birds.

Sick and dead pelicans are turning up on Oregon’s coast and state wildlife officials say they don’t yet know why. The Oregon Department of Fish and Wildlife says it has collected several dead brown pelican carcasses for testing. Lab results from two pelicans found in Newport have come back negative for highly pathogenic avian influenza, also known as bird flu, the agency said. Avian influenza was detected in Oregon last fall and earlier this year in both domestic animals and wildlife – but not brown pelicans. Additional test results are pending to determine if another disease or domoic acid toxicity caused by harmful algal blooms may be involved, officials said. In recent months, domoic acid toxicity has sickened or killed dozens of brown pelicans and numerous other wildlife in California. The sport harvest for razor clams is currently closed in Oregon – from Cascade Head to the California border – due to high levels of domoic acid detected last fall.Brown pelicans – easily recognized by their large size, massive bill and brownish plumage – breed in Southern California and migrate north along the Oregon coast in spring. Younger birds sometimes rest on the journey and may just be tired, not sick, officials said. If you find a sick, resting or dead pelican, leave it alone and keep dogs leashed and away from wildlife. State wildlife biologists along the coast are aware of the situation and the public doesn’t need to report sick, resting or dead pelicans. — Gosia Wozniacka covers environmental justice, climate change, the clean energy transition and other environmental issues. Reach her at gwozniacka@oregonian.com or 971-421-3154.Our journalism needs your support. Subscribe today to OregonLive.com.

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