One dolphin plays three roles: Why does a dolphin that has been alone for five years talk to itself? | Nature Trumpet

Welcome to the 70th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) Chimpanzees also have a desire to perform

2) A large number of bees died in car accidents

3) Smart elephants take a shower with a hose

4) African penguins are critically endangered

5) Mountain lions change their schedules to avoid humans

6) A lonely dolphin, talking to himself

Chimpanzees also have a desire to perform

Not only humans have the desire to perform in front of an audience, chimpanzees do the same.

Chimpanzees completing touchscreen tasks | Akiho Muramatsu

In a new study, scientists asked chimpanzees to complete some small tasks on a computer touch screen, and arranged several people to observe. The results showed that the more humans watching, the better the chimpanzees performed on the most difficult tasks ; on the contrary, for simple tasks, if there were more humans watching, their performance would deteriorate. Moreover, chimpanzees can distinguish whether the onlookers are familiar or strangers, and familiar people will have a greater impact on their performance - just like humans, they will care more about the opinions of familiar people they see every day.

We subconsciously pay attention to whether there are people around us watching us. Once we find that we are being observed by others, even if we do not deliberately change, our behavior will be unconsciously affected. This "audience effect" can help us establish a good reputation in society and help us survive in the group. This study found that this may not be a unique psychology of humans. Our primate cousins ​​also have it, and they can even be affected by the audience of another species.

Chimpanzees in the wild have a different social environment than those in the lab | Charles J. Sharp

However, this experiment does not mean that wild chimpanzees will also have the desire to perform in front of human audiences. Many chimpanzees participating in the study have always had close interactions with experimenters and other humans, and they participate in training almost every day to get food rewards. Humans are their daily companions. If it is wild chimpanzees that rarely come into contact with humans, the results may be different.

Bee Road Kill

Car accidents happen all the time without us realizing it—and the victims are bees.

In a recently published study, researchers found that car accidents are also a common cause of death for bees. Their experimental method is very simple: before each trip, stickers are placed on the bumper of the car. After the trip, the bees killed by the car on the bumper are removed, the species are identified and counted. In 29 trips totaling 9,334 kilometers, they found that at least one bee died on each trip .

Dead bee on car bumper | Joseph S. Wilson / Wikimedia Commons

The probability of bees being killed by cars varies depending on the region and weather. They found that the bee roadkill rate on a certain section of highway was particularly high, with 50-175 bees dying per trip. About 94,000 vehicles pass through this section of highway every day, and it is estimated that the total number of bees killed every day is millions. This is just a section of highway. If other roads are included, the number of bees killed by car accidents in the western United States every day may even reach billions .

Reducing flowering plants on roads can help protect bees | Sputniktilt / Wikimedia Commons

Bee populations are declining around the world. They are important pollinators and are closely related to human food production. In addition to global warming, the use of pesticides, and reduced habitats, road kill, which has been ignored by humans, is also one of the causes of bee death. Researchers suggest that in order to reduce bee road kill, people can avoid planting flowering plants in the middle and near roads .

Elephant shower

Elephants have once again amazed humans with their ingenuity - an elephant can shower itself with a hose.

Mary is an Asian elephant living in Berlin Zoo. Mary grabs the hose with her trunk and uses it as a shower head. She is very flexible in using it. To wash her back, she grabs the hose and swings it up over her body. She also determines whether a hose is suitable for bathing. If the hose is large and heavy, she will use her trunk instead.

Mary swung the hose over her body to rinse her back | References [3]

Mary uses a hose to bathe, and another elephant, Anchali, has learned to mess with Mary's bath . Anchali would not put his feet directly on the hose, because this would attract criticism from the breeder. So he developed two more clever ways to mess with the water: the first is to pull the hose over and twist it with his trunk to make the water flow messy; the second is to put his trunk on the hose and then lower his body.

On the left is Mary taking a shower, on the right is Ann Charlie twisting the hose and causing damage | Reference [3]

This is another way that Ann Charlie messes up, pressing his nose onto the tube and lowering his body | References [3]

The researchers recorded the interaction between Mary and Ann Charlie and published a paper based on it. This study found that elephants can not only master complex tool use, but also understand the tool use process of other elephants and use the same tools to play tricks on each other. Perhaps in the wild, the interaction between elephants is much more complicated than we previously thought.

African penguins are endangered

African penguins could be extinct in the wild by 2035.

Recently, the African penguin was listed as critically endangered by the International Union for Conservation of Nature (IUCN) , the first penguin species to be classified as critically endangered. They live in South Africa and Namibia. In 1991, there were 42,500 breeding pairs of African penguins, but now there are less than 10,000 breeding pairs left.

An African penguin colony in South Africa | Dietmar Rabich / Wikimedia Commons

How did African penguins get to this point today? Climate change, commercial fishing, and habitat destruction have accelerated their disappearance. Plans to save African penguins have been ongoing - artificial nests have been built in penguin colonies, which has increased the number of penguin eggs hatched by 16.5%; the South African government has also launched a fishing ban plan, prohibiting fishing in penguin breeding areas from 2008 to 2019, which makes it easier for penguins to get food, and the survival rate of cubs has also increased, and the number of penguins has increased by 1%; the penguin rescue team has also rescued thousands of injured and abandoned penguins and released them back into the wild.

African penguins suffer from heatwave during breeding season | Mike Scott / Wikimedia Commons

However, even though efforts to save African penguins have never stopped, their numbers are declining faster and faster due to oil spills, noise pollution, etc. Now, they are only one step away from extinction, and the public is asking the South African government to take urgent action to start a larger fishing ban policy and control the number and speed of ships to save African penguins and all species related to them.

Cougars change their routine

To avoid humans, mountain lions have to go out in the middle of the night.

A new study found that mountain lions living in remote areas generally prefer to be active at dawn and dusk, while mountain lions living in areas with high human density prefer to go out in the middle of the night . This is because humans are increasingly interested in activities in nature, and more outdoor enthusiasts are starting to ride bicycles, hike and jog, with early morning and evening being their popular activity times. In order to avoid humans, mountain lions have to adjust their schedules and move around at night when no one is around.

Cougar P65 and its babies | National Park Service

Mountain lions have made too many compromises because of humans, and they are often killed because of it. In the Los Angeles area, more than 30 mountain lions have been killed by human vehicles. They have also been affected by wildfires, rodenticides, fragmented habitats and decreasing genetic diversity, which have accelerated the decline of mountain lions. A 2019 study also showed that even the sound of human speech is enough to scare away mountain lions.

The famous mountain lion P22 had to be euthanized because of serious injuries in a car accident | National Park Service

This study shows that in addition to cruel and direct events such as roadkill, human activities are having more indirect impacts on wildlife. However, from a positive perspective, when human activities are inevitable, at least mountain lions can adjust their behavior to adapt to humans and use a new routine to allow themselves and humans to coexist.

Dolphin talking to himself

A lonely dolphin was found in the Baltic Sea, always talking to itself in the ocean.

Its name is Delle, a bottlenose dolphin. Bottlenose dolphins live in groups and are not usually found in the Baltic Sea. However, five years ago, locals discovered that Delle had settled here alone . Out of curiosity, researchers recorded Delle's voice using underwater recording equipment.

Bottlenose dolphin | caroline legg / Wikimedia Commons

The results showed that Delai was talking a lot even though he was alone. During the 69 days of recording, he made 10,833 sounds, including whistles, knocks, low-frequency tones, etc. What's even more strange is that each dolphin usually has its own signature whistle, but Delai made three different whistles - if the researchers hadn't known in advance that Delai was a lone dolphin, they would have thought that there were at least three dolphins talking.

Bottlenose dolphins tend to live in groups. | Walter Baxter / Wikimedia Commons

At first, the researchers speculated that Delai might be trying to communicate with humans, but this speculation was immediately overturned because Delai continued to talk to himself when there were no humans around. The researchers thought that maybe Delai was expressing his emotions involuntarily, just like humans can't help laughing when they see something funny when they are alone; it is also possible that because of loneliness, Delai had to use self-talk to distract himself.

Another theory is that Delai is trying to attract the attention of other dolphins, and that he is still looking for his own companions. But this is unlikely, as he has been alone for several years and should have realized that his chances were slim.

References

[1]https://www.cell.com/iscience/fulltext/S2589-0042(24)02416-7

[2]https://www.tandfonline.com/doi/full/10.1080/27658511.2024.2424064

[3]https://www.cell.com/current-biology/fulltext/S0960-9822(24)01371-X

[4]https://phys.org/news/2024-11-critically-endangered-african-penguins-peace.html

[5]https://www.sciencedirect.com/science/article/pii/S0006320724003744

[6]https://www.tandfonline.com/doi/full/10.1080/09524622.2024.2422092

Author: Cat Tun

Editor: Mai Mai