Birds called "stupid birds" are actually very smart | Nature Trumpet

Welcome to the 77th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) Wolves domesticated themselves into dogs because they loved snacks

2) Using AI to automatically monitor animal emotions

3) Birds called "dumb birds" are actually very smart

4) With only two northern white rhinos left, new hope finally comes

5) Large animals are more likely to get cancer

6) Animals’ schedules are actually quite flexible

Self-domestication of dogs

Scientists discover: Wolves may have domesticated themselves into dogs!

This possibility has long been proposed: starting about 30,000 years ago, wolves accidentally discovered areas where humans lived and began to feed on human food scraps; after encountering this easy-to-obtain food source, many wolves began to hang around humans and even try to please humans for snacks . These wolves gave birth to offspring with similar personalities of the opposite sex, and 15,000 years ago they became early dogs, turning human food into a "iron rice bowl".

Wolves used to be very majestic | Mikkel Houmøller / Wikimedia Commons

Another view is that wolves could not have domesticated themselves into dogs in such a short period of time, and that selective breeding by humans must have accelerated the process . In other words, humans selected the most docile wolves to help them hunt and let them breed, and this artificial selection led to the birth of domestic dogs.

In a new study, scientists created a statistical model and found through the model's deduction that wolves could have domesticated themselves into dogs over 15,000 years without the involvement of artificial selection. However, this requires two conditions to be met: first, wolves must eat human food near human living areas; second, females will choose mates with similar temperaments, that is, males who are more gentle and can coexist with humans.

Are you saying that my ancestors domesticated themselves into this state? | Mikkel Houmøller / Wikimedia Commons

Dogs are the first domesticated animals. Studying how wolves became dogs can help us better study the domestication process of other animals. For example, the ancestors of domestic cats came to human living areas 10,000 years ago and may have been domesticated into today's domestic cats in a similar process.

AI monitors animal emotions

AI can not only translate human language, but also animal emotions.

Decoding animal emotions is divided into two aspects: one is their arousal level, which can be judged by their heart rate, cortisol levels and behavior, which is relatively simple; the other is whether their emotions are positive or negative, which is important for animal welfare but difficult to assess. Previous studies have found that when animals of different species express the same emotion, their vocal characteristics are consistent , such as when they are happy, their calls last for a shorter time.

Different animals use similar acoustic signatures to express the same emotions | Kuebi / Wikimedia Commons

Based on this discovery, scientists recently built a machine learning model that can translate the calls of seven ungulates (cows, sheep, horses, pigs, etc.) into whether they are happy, negative, or in pain . The overall accuracy of this model in emotion classification can reach 89.49%, and the accuracy of judging the emotions of pigs is as high as 99.91%.

The model translated the emotions of the pig most accurately | Guido Gerding / Wikimedia Commons

With such a model, the next step is to develop automated tools for real-time monitoring of animal emotions . Whether it is livestock farming, animal protection, or daily veterinary work, such tools can be used to determine whether animals are happy or sad at the first time. Understanding animals' emotions can make them live better.

"Stupid Bird" is not stupid

Crows and parrots are recognized as geniuses among birds, while large birds such as ostriches are always called stupid birds. But recently, scientists reversed the reputation of large birds - they can also solve difficult problems!

Scientists gave ostriches, rheas and emus a task: in front of them hung a transparent disc with food in some slots; only by rotating the disc and aligning the holes with the slots could they eat the food rewards inside.

Mission setup and disintegration of the American Ostrich | References [3]

The experiment involved three emus, two rhinos and four ostriches. As a result, all three emus figured out how to solve the problem the first time - they used their mouths to rotate the disc clockwise or counterclockwise, accurately aligned the hole with the food slot, and ate the food. Moreover, this was not a coincidence. In 90% of cases, the emu could move the hole in the right direction.

An American ostrich also succeeded in getting the food. But in addition to this conventional solution, it also had a more innovative way: it simply loosened the bolts, dismantled the turntable , and easily ate the food in all the food troughs.

Emu: Don't underestimate my intelligence | Fay Clark

Paleognaths, represented by the American ostrich, are the oldest branch of existing birds. Their brains are the largest in absolute size among existing birds, but the relative proportion of their brains to their bodies is the smallest among birds, so they have always been considered to be members of birds with low intelligence. This study shows that a smaller relative proportion of the brain does not mean a lower IQ ; on the contrary, paleognaths are not stupid, and they also have excellent technological innovation capabilities. The development of birds' intelligence during evolution may have occurred much earlier than we previously thought.

The northern white rhino may be saved

There are only two female northern white rhinos left, and perhaps this year there will be new hope.

Najin and her daughter Fatu are the last two northern white rhinos on Earth. Although scientists have previously collected sperm from male northern white rhinos, both Najin and Fatu have uterine problems and cannot conceive through in vitro fertilization. Fortunately, Fatu can still produce viable eggs, which scientists can collect, perform in vitro fertilization, and then implant the resulting embryos into the uterus of female southern white rhinos - the southern white rhinos are close relatives of the northern white rhinos and are the most suitable surrogate mothers.

The last two northern white rhinos on Earth: Najin and his daughter Fatu | References [4]

After long-term efforts, scientists have now achieved a major breakthrough: they have created 36 fertilized embryos and hope to transplant them into the uterus of a surrogate southern white rhino this year.

However, it is too early to celebrate - no one can be sure of the success rate of embryo implantation, and pregnancy takes up to 18 months, and it is hard to guarantee that there will be no accidents during this period. A year ago, scientists successfully created a southern white rhino embryo and implanted it into the uterus of a surrogate mother, but the surrogate mother died of a bacterial infection before the pregnancy was detected.

Sudan, the last male northern white rhino, died in 2018 | References [4]

In order to save the northern white rhino, scientists around the world are working hard: Japanese scientists are using stem cell technology to create more northern white rhino eggs and sperm, and may be able to create northern white rhino embryos in four years; scientists in Oxford, England are trying to extract immature eggs from the ovarian tissue of dead rhinos. They all hope to create a northern white rhino baby while Najin and Fatu are still alive , so that the cub can grow up under the care of Najin and Fatu and learn how to become a real northern white rhino.

Cancer in large animals

Cancer is related to gene mutations in cells. The more times a cell divides, the higher the chance of cancer. However, in people's impression, large animals are not so prone to cancer.

In the 1970s, British pathologist Peto proposed a widely accepted theory, the "Peto's Paradox", which holds that there is no relationship between the incidence of cancer and the number of somatic cells in different species . The most typical example is that whales and elephants are much larger than humans, but the incidence of cancer in humans is much higher than them.

Elephants are bigger than humans, but have a lower cancer rate | Asier Larramendi / Wikimedia Commons

Recently, a new discovery overturned this theory. Scientists studied the largest data set ever, including autopsy cancer records of 90 mammals, 79 birds, 31 amphibians and 63 reptiles. The results showed that, in general, larger species do have higher cancer rates . The Peto paradox was proposed before because the number of species sampled at the time was small and the amount of data for each species was not high, which led to inaccurate conclusions.

But Peto's paradox is not entirely without basis - species such as elephants and naked mole rats have evolved anti-cancer mechanisms, making their actual cancer rates much lower than expected . There are 20 copies of the TP53 gene in the elephant genome, but only one in humans. The TP53 protein can detect DNA damage, initiate repair or apoptosis, and reduce the probability of cancer. Although naked mole rats are small in size, they can live up to 30 years and almost never get cancer because they have hyaluronic acid that inhibits excessive cell proliferation.

Naked mole rats don't get cancer | John Brighenti / Wikimedia Commons

Humans influence animal circadian rhythms

Scientists conducted a comprehensive survey of animals' daily routines and found that their lives are completely different from what humans imagine!

In a recently published study, the research team collected 8.9 million detection data from 20,000 cameras across six continents and 38 countries and regions, and analyzed the activity patterns of 445 mammals around the world. The results are surprising - we think that animals' schedules are as rigid as alarm clocks, but in fact their biological clocks may be more flexible than those of workers . For example, American black bears, which are considered diurnal animals, have become night owls in some areas, and are active during both day and night in other areas.

This study included the largest dataset ever | References [6]

In areas where humans live, one-third of animals have changed their daily routines , with striped skunks, North American porcupines and gray foxes all switching to a pattern of staying at home during the day and going out at night. Scientists believe this is because their original activity times have become risky due to humans, so they have to avoid the peak period of human presence to reduce survival pressure.

To avoid humans, striped skunks stay out at night | National Park Service

The scientific community generally divides animals into diurnal, nocturnal, crepuscular (active at dawn and dusk), or those that appear and disappear randomly during the day and night; but among the 445 species they studied, only 39% of the animals fit these traditional descriptions . Among the 126 species they quantitatively evaluated, as many as 74% of the animals can flexibly switch their diurnal activity patterns to adapt to the environment at the time.

References

[1]https://royalsocietypublishing.org/doi/10.1098/rspb.2024.2646

[2]https://www.cell.com/iscience/fulltext/S2589-0042(25)00094-X

[3]https://www.nature.com/articles/s41598-025-88217-8

[4]https://phys.org/news/2025-02-quest-extinct-rhinos.html

[5]https://www.pnas.org/doi/10.1073/pnas.2422861122

[6]https://www.science.org/doi/10.1126/sciadv.ado3843

Author: Cat Tun

Editor: Mai Mai

This article comes from GuokrNature (ID: GuokrNature)

If you need to reprint, please contact [email protected]