Philippa Kaur

Prominent ecologist Thomas Crowther, whose research on trees has influenced figures including US President Donald Trump, will depart the prestigious Swiss Federal Institute of Technology in Zurich (ETH Zurich) after the institution said that it would not renew his contract. ETH Zurich says it has received “reports of alleged misconduct on a variety of levels” and has lost trust in the assistant professor.Crowther and ETH Zurich declined to comment on the allegations. Crowther says that he is in talks to relocate his laboratory, which employs 40–60 people.“The team is doing its best to be resilient, but most of us are in shock, and there is grief over what has been lost,” says Emily Clark, the group’s manager, who describes the atmosphere in the lab as quiet and sad. Members of Crowther’s team were told in mid-December that they would lose their jobs by September because the lab is being dissolved, according to a member who asked to remain anonymous.Crowther rose to prominence while doing postdoctoral research at Yale University in New Haven, Connecticut. In 2015, he was lead author on a paper published in Nature1 that suggested there were nearly eight times more trees growing on Earth than expected. His research garnered attention from influential people and inspired the launch a high-profile tree-conservation initiative by the World Economic Forum (WEF), which received support from the first Trump administration. He was dubbed the ‘Steve Jobs of ecology’ and profiled by journals including Nature and Science.Millions in fundingIn 2017, Crowther moved to ETH Zurich on a tenure-track professorship. Within a year, he had secured 17.7 million Swiss francs (US$19.5 million) in funding from a Dutch non-profit foundation called DOB Ecology in Veessen for a 13-year project to understand how ecological processes drive the carbon cycle and climate.In late 2024, Swiss media reported that eight people had made allegations against Crowther to the university. Details of the allegations have not been reported, and ETH Zurich and Crowther declined to comment to Nature on the content of the press reports.In a statement to Nature, ETH Zurich said that last July its leadership decided to “have the allegations informally clarified by an external law firm”. It added: “ETH Zurich President, Joël Mesot has decided to no longer employ the scientist following expiration of the scientist’s tenure process. Following a careful evaluation, the ETH Zurich President reached the conclusion that there is no longer a basis of trust for a permanent employment contract.”Crowther is on administrative leave and his contract, which expires at the end of September, will not be renewed, according to the statement. “The initiated clarifications are still ongoing. Please understand, that we cannot comment further on this matter,” ETH Zurich said.Crowther told Nature that he is contemplating offers from two institutions, one in Europe and one in Asia, to relocate his lab. “I am still considering where might be the best place for the next phase of the group,” he says.

Enjoying our latest content?
Login or create an account to continue

Access the most recent journalism from Nature’s award-winning team
Explore the latest features & opinion covering groundbreaking research

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD More

Carnivore ecologist Tyus Williams crouches to eye level to install a wildlife camera in Bayview Park, San Francisco, California.Credit: Dr Christopher J. SchellWorking scientist profilesThis article is part of an occasional series in which Nature profiles scientists with unusual career histories or outside interests.Tyus Williams says he grew up as a nerdy, neurodiverse, science-loving child who was a little bit unsure of his place in the world. “When you’re a young, curious Black kid with ADHD and autism spectrum disorder, you feel like you were born into a world that wasn’t made for you,” he says. Today, he’s a budding carnivore ecologist with fans who range from readers of his first children’s book to online social-justice warriors and colleagues who admire his brand of equity-seeking science. “I knew at the age of six what I wanted to be,” Williams says. That meant working with animals, especially wildlife. But after a school job at an animal hospital in Alpharetta, Georgia, where he grew up, Williams realized that he couldn’t bear to euthanize pets. Instead, he chose a research path.Williams studied wildlife science at the University of Georgia in Athens. His early research included contributions to surveying salamanders in the Appalachian mountains, jaguars (Panthera onca) in Belize and sea turtles and eastern diamondback rattlesnakes (Crotalus adamanteus) in coastal Georgia.TikTok’s dancing chemist catalyses joy in studentsAs someone who didn’t always fit in, Williams has a soft spot for carnivores, which can be seen as menaces or threats, particularly in urban areas.“My mom would never let me have a snake,” he says, “but I was always interested in carnivorism.” He is now working on his PhD dissertation at the University of California, Berkeley, where he splits his time between urban ecologist Chris Schell’s group and that of wildlife ecologist Justin Brashares. Williams examines how human society exacerbates the effects that outdoor domestic cats — now considered invasive — have on other species. The research groups study urban ecology, justice and equity.‘Your friendly neighbourhood ecologist’Schell first met Williams at an event for Black mammologists. The two bonded over a shared interest in finding links between ecology and sociology — in other words, in how human behaviour influences what animals do in their environments.“He has the genuine love of science you’d see in a five-year-old,” Schell says. Even in the burnout-prone academic world, Williams seems to have maintained that. Yet, “I don’t think it’s lost on Tyus that he’s one of the few Black students in the department”, Schell says. “Tyus has struggled with impostor syndrome in an incredibly big way.”Despite these struggles, Williams cultivates a steady social-media outreach effort alongside his studies. He led social media for the Cougar Network, a US research organization, and his children’s book Big Cats (A Day in the Life) was published in 2022.Working Scientist career profilesThe book is aimed at children six to eight years old who want to delve into the scientific details — just as Williams did at that age. His publisher, Sam Priddy, at Neon Squid Books, says the target audience is a little kid who “loves facts, learning things, collecting them and telling their friends and family about them”. For an author, “we wanted someone who had actually been with these animals in the wild and tracked them”, says Priddy. In 2018, Williams launched #SciQFriday on X (formerly Twitter). Through this, he spent a couple of years hosting weekly Q&As with dozens of life scientists, from herpetologists to virologists and microbiologists, before turning to newer platforms such as TikTok.Also on social media, Williams, who describes himself on TikTok as “your friendly neighborhood ecologist”, has gained a following for posts that address current issues from a scientific and social-justice perspective. An example is this one explaining why the disappearance of pets in Springfield, Ohio, is probably down to coyote predation, and not — as put forth by US president-elect Donald Trump during his election campaign — to their being eaten by Haitian immigrants. Williams often lists references in the bottom corner of the TikTok videos he records in his apartment, with his favourite Spider-Man poster in the background.Williams beside a sign at Oyster Bay Regional Shoreline in San Leandro, California, warning people not to abandon domestic cats in the park. Credit: Tyus D. WilliamsAs a Millennial scientist, Williams often blurs the boundaries between personal and professional identity. His chatty, information-packed style has earned him a following of more than 31,700 accounts on TikTok, with more than 1.2 million likes. He’s not afraid to post a video on the science behind textured hair, with half a dozen citations, because that’s what he himself is interested in. Williams describes his own hair as “if Medusa and Hydra got together, and this was their love child”. He goes on to explain that the concept of ‘good’ or ‘bad’ hair is problematic and driven by white supremacist ideals of smooth, straight hair, and the idea that curly or textured hair is inherently less desirable.“The different types of textures we see, and even curly hair in its kinkiest form, is a great example of the living phenomena of adaptive selection under selective pressures,” he explains, outlining research hypothesizing that textured hair developed as a cooling mechanism as humans evolved in equatorial Africa. Researchers showed that the tighter the curl, the better heat can dissipate. The video lasts nearly five minutes, an eternity in the world of TikTok.But social-media super-sharing typifies Williams’s style. “Engaging in a long philosophical debate about the connection from things that seem completely unrelated to something we do in the lab,” Schell says. “That’s quintessential Tyus.”Social justice in the wildWilliams’s research draws complex links between racism and colourism (prejudice against people of the same ethnicity but with darker skin tones). It includes the effects of biases against darker animals and the spiritual significance of rare, white versions of species including buffalo (Bison bison), bears and elk (Cervus canadensis). A study that he co-authored last year highlighted how human societies interact with and protect unusual black or white coyotes (Canis latrans), eastern grey squirrels (Sciurus carolinensis) and white- and black-tailed deer (Odocoileus virginianus and O. hemionus), whose fur is typically brown or grey1.

Enjoying our latest content?
Login or create an account to continue

Access the most recent journalism from Nature’s award-winning team
Explore the latest features & opinion covering groundbreaking research

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD More

The Comment article ‘How biodiversity credits could help to conserve and restore nature’ suggests proper design could make biodiversity-credit markets work (A. Antonelli et al. Nature 634, 1045–1049; 2024). However, this overlooks fundamental flaws that make these credits even more problematic than carbon credits.
Competing Interests
The author declares no competing interests. More

“When I was a child living on the southern Pacific coast of Costa Rica, my parents would take me to see golden-mantled howler monkeys (Alouatta palliata palliata) in the forest most weekends. Howler monkeys are like big, hairy gardeners, spreading seeds from many trees. I understood at an early age that if we preserve the forest, we preserve the species in it.For the past decade, I’ve studied the behaviour of howler-monkey troops in Guanacaste, a region in northern Costa Rica where tourism is growing rapidly and hundreds of monkeys die from electrocution each year. For my master’s degree at the University of Costa Rica, I evaluated how monkeys use modern structures such as power lines to navigate through an urban area. I ended up taking a lot of electrocuted monkeys to rescue centres. We are documenting how this species’ behaviour is changing in real time.We track where troops move and what they’re eating, and note the percentage of forest cover in each location. Although we don’t know whether the overall number of monkeys is declining, we do know that troops located in healthy protected forests, for example in a national park, have roughly 25–45 individuals, compared with an average of only 7 in urban troops.

Enjoying our latest content?
Login or create an account to continue

Access the most recent journalism from Nature’s award-winning team
Explore the latest features & opinion covering groundbreaking research

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD More

Natural History of Silence Jérôme Sueur Polity (2024)“Shhh!” This is the demand that eco-acoustics researcher Jérôme Sueur makes of humanity. The racket of technology — emanating from ships, aeroplanes, machinery and more — permeates even the remotest corners of the planet.Sueur explores the impact of this ever-present hum on the animal world in Natural History of Silence. He offers rich descriptions of the sonic lives of several species, such as the rhythmic mating chirps of cicadas and the crackling and popping sounds produced in coral reefs. When human-made noise drowns out nature’s symphony, ecosystems become disrupted, Sueur argues. For instance, experiments around Moorea Island, French Polynesia, show that motorboat noise upsets free-swimming juvenile corals, which rely on reef sounds to find a suitable place to settle. In quieter, protected areas, coral attraction to reefs is much higher (D. Lecchini et al. Sci. Rep. 8, 9283; 2018).Tiny beauty: how I make scientific art from behind the microscopeAnyone new to the science of sound will be able to learn its foundations in this book. Sueur explains how animals create, use and perceive sound and how researchers have used this knowledge to understand wildlife behaviour. Tucked between travelogue-style chapters and wandering philosophical ruminations, there is a primer on key terms and theories, such as the acoustic niche hypothesis, which posits that each species has a unique acoustic space to enhance communication with its peers and limit sound competition from other species. The book also includes an abridged evolutionary history of how animals developed the ability to send and receive vibrations.Be silent and tune inSueur’s thesis is this: silence is a crucial resource, like food or water, that species compete for to survive. “Making sound is an essential part of being alive,” he writes. But humans need to “make sure we are not more alive than others”.Sueur offers practical advice on how to do that. A student of writings by naturalist John Muir and poet Walt Whitman, he encourages readers to seek solitude in a remote location to grasp the profound value of turning the noise dial down. Be silent and tune in, he writes, for a naturalist’s meditation focuses on the external rather than internal world. The book starts with one such excursion — a winter walk in the Chartreuse Mountains in France — where, Sueur writes, “for the very first time, I experienced silence in a natural world teeming with life”.Birds (such as the white-crowned sparrow, pictured) need to sing louder to be heard over the noise of nearby traffic.Credit: Kurt Stricker/GettyThe book’s central theme revolves around the concept of Umwelt, a word used by German biologist Jakob von Uexküll to refer to the sensory world unique to each species, shaped by its sensory organs. An animal’s Umwelt is the limited slice of the world it can perceive and defines its immediate environment. Sueur suggests that constant noise disrupts many species’ perception of the world and hinders people’s ability to have empathy for others. Because noise “gets in the way”, it secludes us from the natural rhythms of the ecosystem.The Risoux forest, a protected area in the Jura Mountains that straddles the border between France and Switzerland, is a prime example. There, hazel grouse (Tetrastes bonasia) and Eurasian pygmy owls (Glaucidium passerinum) fly, and so, too, do planes in a “physiological and psychological assault which is repeated every five minutes”, Sueur writes. “Up there, the airline companies, the pilots, the tourists, sometimes including ourselves, are in the process of contaminating an entire forest without realizing it and are passing by without even a gesture of apology.”

Enjoying our latest content?
Login or create an account to continue

Access the most recent journalism from Nature’s award-winning team
Explore the latest features & opinion covering groundbreaking research

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD More

Much of the excitement about AI over the past decade has come from the achievements of neural networks — systems built on an analogy of how the human brain processes information through collections of neurons. Deep learning, in which data pass through many layers of a neural network, was what led to the creation of the chatbot ChatGPT. The sperm whale, elephant and marmoset studies, however, used earlier forms of AI known as decision trees and random forests.
A decision tree is a classification algorithm that looks like a flow chart. It might ask, for example, whether the sound it has been given has a frequency above a certain value. If yes, it might then ask whether the call lasts for a certain length of time, and so on, until it has decided whether the call matches the acoustic variables it was trained to look for using human-labelled data sets. A random forest is a collection of many decision trees, each constructed from a randomly chosen subset of the data.
Kurt Fristrup, an evolutionary biologist at Colorado State University who wrote the random-forest algorithm for the elephant project, says that tree-based algorithms have several advantages for this kind of work. For one, they can work with less information than is required to train a neural network, and even thousands of hours’ of recordings of animal calls is still a relatively small data set. Furthermore, because of the way that tree-based algorithms break down the variables, they’re not likely to be thrown off by mislabelled or unlabelled data.
The random forest also provides a way to verify that similar calls match: different calls that show the same features should each end up in the same ‘leaf’ of an individual tree. “Since there were on the order of a thousand of these trees, you get a fairly fine-grained measure of how similar two calls are by how often they landed in the same leaf,” Fristrup says.

Your browser does not support this video

An elephant reacts to the playback of a call that was originally addressed to her. Credit: Mickey Pardo

An elephant reacts to the playback of a call that was originally addressed to her. Credit: Mickey Pardo

It is also easier to see how a random-forest algorithm came to a particular conclusion than it is with deep learning, which can produce answers that leave scientists scratching their heads about how the model reached its decision. “Deep-learning models make it possible or even easy to get all kinds of results that we can’t really get any other way,” Fristrup says. But if scientists don’t understand the reasoning behind it, they might not learn “what we would have learnt had we got into it by the older, less efficient, and less computationally intense path” of a random forest, he says.
Despite this, the ability of a neural network to generalize from a relatively small, labelled data set and discover patterns by examining large amounts of unlabelled data is appealing to many researchers.
Machine-learning specialist Olivier Pietquin is the AI research director at the Earth Species Project, an international team headquartered in Berkeley, California, that is using AI to decode the communications of animal species. He wants to take advantage of neural networks’ ability to generalize from one data set to another by training models using not only a large range of sounds from different animals, but also other acoustic data, including human speech and music.
The hope is that the computer might derive some basic underlying features of sound before building on that understanding to recognize features in animal vocalizations specifically. This is the same way in which an image-recognition algorithm trained on pictures of human faces learns some basic characteristics of pixels that describe first an oval and then an eye. The algorithm can then take those basics and recognize the face of a cat, even if human faces make up most of its training data.

Olivier Pietquin (back row, second left) and other members of the Earth Species Project are attempting to decode animal communication. Credit: Earth Species Project

Olivier Pietquin (back row, second left) and other members of the Earth Species Project are attempting to decode animal communication. Credit: Earth Species Project

“We could imagine using speech data and hope that it will transfer to any other animal that has a vocal tract and vocal cords,” Pietquin says. The whistle made by a flute, for example, might be similar enough to a bird whistle that the computer could make inferences from it.
A model trained in this way could be useful for identifying what sounds convey information and which ones are just noise. To work out what the calls might mean, however, still requires a person to observe the animal’s behaviour and add labels to what the computer has identified. Identifying speech, which is what researchers are currently trying to achieve, is just a first step towards comprehending it. “Understanding is really a tough step,” Pietquin says. More

Download Nature hits the books 09 December 2024Zoologist Arik Kershenbaum has spent his career studying animals and how they communicate in the wild. In his book Why Animals Talk: The New Science of Animal Communication, Arik takes a deep dive into the various forms of communication, from wolf howls to gibbon songs, to look at how different species get their points across, why they do it the way they do, and what insights they provide into our own use of language.Why Animals Talk: The New Science of Animal Communication Arik Kershenbaum Penguin (2024) Music supplied by SPD/Triple Scoop Music/Getty ImagesWolf howl via NPS & MSU Acoustic Atlas/Jennifer JerrettSlowed down dolphin whistle via Arik KershenbaumHyrax song via Arik KershenbaumPileated gibbon song via Rushenb CC BY-SA 4.0Never miss an episode. Subscribe to the Nature Podcast on Apple Podcasts, Spotify, YouTube Music or your favourite podcast app. An RSS feed for the Nature Podcast is available too. More

Living on Earth: Life, Consciousness and the Making of the Natural World Peter Godfrey-Smith William Collins (2024)Philosopher Peter Godfrey-Smith has devoted his career to examining how animal minds evolved. He blends formidable analytical skills with a deep curiosity about the natural world, mostly experienced at first hand in his native Australia. While writing his latest book, Living on Earth, he spent many hours scrutinizing noisy parrots and cockatoos in his back garden, weeks observing gobies building underwater towers made of shells and seaweed and years closely watching how octopuses behave (P. Godfrey-Smith et al. PLoS ONE 17, e0276482; 2022). The result is an inclusive perspective on Earth’s many distinct minds and agents that urges readers to consider humans’ collective choices and their diverse consequences.Is ‘speciesism’ as bad as racism or sexism?Living on Earth offers an extended philosophical meditation on life, mind, the world and our place in it, completing a trilogy of works on the nexus of agency, sensation and felt experience. His 2016 book Other Minds explored octopus cognition and evolution. And Metazoa (2020) appraised the subjective experiences of animals, concluding that there exists an “animal way of being” that arises from the integration of sensory information in nervous systems. This implies that sentience and subjectivity — life-shaping combinations of perception, goals and values — are widespread across the tree of life.In his latest book, the author casts his net wider still, asking how the minds and agency of living things have affected Earth. “The history of life is not just a series of new creatures appearing on the stage,” he notes. “The new arrivals change the stage itself.”The arrival of animalsGodfrey-Smith starts by explaining how the earliest lifeforms altered our planet’s chemistry and geology. Photosynthetic bacteria released oxygen, which gradually blanketed Earth and left their mark on the composition of rocks and minerals in the form of new minerals, such as malachite. Eventually, enough oxygen accumulated to power the evolution of aerobic life — a stark example of the transformative impact of some lineages constructing environments in which others can thrive.The arrival of animals that could undertake purposeful actions, such as feeding, interacting with others and gathering information, meant that Earth was transformed further. As their capacities for controlled movement evolved, animals became able to actively engineer their environments. Defecating migrating whales, for instance, redistribute nutrients and support other species in the food web, which in turn benefits the whales.The lyrebird (Menura novaehollandiae) mimics the calls of other bird species.Credit: GettyFocusing on communication, Godfrey-Smith describes its powerful effects with a riot of avian sound and colour. On a rainforest walk, he encounters a lyrebird (Menura sp.), known for its expert mimicry, which it uses in part to attract mates. “In quick succession, he was a whipbird, a black cockatoo, a Laughing Kookaburra, a magpie, and many I didn’t know”. Fork-tailed drongos (Dicrurus adsimilis) use alarm calls copied from other species, to cheat other species out of well-earned meals (T. P. Flower et al. Science 344, 513–516; 2014). This capacity to deceive, as well as to communicate honestly, further transforms what an organism can experience and what effect it has on its surroundings, by creating ever-changing visual and audio environments.Turning to hominids, the author considers culture, which he characterizes as the ability to learn sets of norms that are passed between peers and down generations. Humans are primed for such learning, exhibiting an awareness of rules early in childhood. He argues that the ways in which people help others to learn those norms — through informal apprenticeships, for example, in which older individuals teach skills to younger ones — sets us apart from many other species. They have also enabled humans to develop distinctive aspects of communication, such as an ability to understand from a person’s words what they are thinking. This skill makes it possible to coordinate behaviour more effectively, helping people to live together in large, stationary communities and thereby increase humanity’s ability to control and modify nature, for good or ill.Human influencesThe fact that humans can exert agency in many ways — through physical actions, culture and communication — goes hand in hand with increased abilities to change the world. Thus, Godfrey-Smith argues, all these aspects of human agency come with a responsibility to think hard about what forms of control or modification of other living beings are ethical. Our intuitions of harm, fairness and loyalty, along with basic norms derived from habits of nurture and protection, such as caring for one’s offspring, must all be considered to define moral imperatives for societal behaviour towards all forms of life.Take modern industrial farming — which should cease, the author contends. People can understand how it arose from the need to feed growing communities. But individuals can also engage in imaginative and sympathetic ethical reflection that considers the lives of factory-farmed animals. If the animals that humanity controls in this manner do not seem to have “a life worth living”, Godfrey-Smith asserts, people should acknowledge that these practices are unethical.A tour of the evolution of mindsHowever, that doesn’t mean it’s obvious what should be done instead. Godfrey-Smith emphasizes that the most ethical choice is not necessarily to relinquish control over other living beings and stop farming. After all, human actions of control and modification are part of the natural world, too. Some people might advocate justly that humane farming — such as raising animals in environments with the freedom to roam and a healthy diet, or using effective stunning methods before they’re killed — is an appropriate solution. Others might think this is a contradiction in terms.The author is well aware that human actions have produced huge, planet-wide problems, including climate change. However, he encourages people to use their agency and address such problems on a local level, at scales that individuals can most readily influence. For example, I am more likely to be effective at improving habitats by coordinating with members of my local township to reduce the waste that enters a nearby ecosystem than at reducing fossil-fuel use by industry worldwide.Controversially, Godfrey-Smith wants us to see our moral responses to these two types of problem — habitat degradation and climate change — as separable. This is in part because they prompt different types of ethical reflection and in part because they demand distinct kinds of coordinated control and modification. In terms of ethical reflection, people are more likely to take actions that support and protect the lives and experiences of other species when they value them explicitly. The lives of local bird or butterfly populations are more tangible, and so easier to value, than is life on a global scale. And in terms of coordinated control, collaborative efforts with one’s neighbours can have great staying power and effectiveness at a scale that differs from governmental policies that provide incentives for individual consumers across society.In places, Godfrey-Smith’s considered tone and judicious presentation of subtleties might seem frustrating, considering the stark situations we face because of humanity’s misused agency. If ‘we’ are in this together with other life on Earth, then don’t we need to act accordingly (and urgently)? Yet solutions are not black and white. For example, reducing pain by experimenting on fewer animals does not necessarily mean that researchers should aim to cease experimentation for medical benefit. Such trade-offs are central to Godfrey-Smith’s narrative and what make it so insightful.Overall, Living on Earth successfully fills readers with wonder at the natural world, while maintaining a clear, analytical style. Godfrey-Smith argues compellingly that, although we live in a world shared with other species, humans have distinctive responsibilities because of the “unusual efficacy in our actions”. I tip my hat to his uncanny ability to make his case in a temperate voice with both intellectual acuity and passionate conviction. More