Which tentacle of a starfish is the head? The answer is: All of them! | Nature Trumpet

Welcome to the 47th issue of the Nature Trumpet column. In the past two weeks, we have collected the following natural news and research worth reading:

1) After more than 60 years, a rare echidna reappears

2) To protect bighorn sheep, domestic sheep have to graze elsewhere

3) Chimpanzees scout each other and decide on tactics based on enemy situations

4) Starfish, a head running around with lips

5) Wolves learned to eat sea otters and gained experience

6) New discovery of brain-computer interface: mice can also imagine

Rare echidna spotted again

The strange animal with an anteater's nose, a mole's feet and a hedgehog's spines finally reappeared.

Fantastic Beasts | Expedition Cyclops

It is the Attenborough long-beaked echidna (Zaglossus attenboroughi), which has only been recorded once before, in 1961. If it hadn't appeared again this time, scientists would have guessed that it had become extinct. It is one of only five monotremes in the world, and like the platypus, it is an egg-laying mammal . It has almost no close relatives on the evolutionary tree and has evolved quietly and alone for 200 million years.

Cyclops Mountains | Expedition Cyclops

This year, in order to find Attenborough's long-beaked echidna, an international scientific expedition team came to the place where it appeared more than 60 years ago - the Cyclops Mountains in Indonesia, a dangerous mountain range that almost no one has set foot on. Echidnas are active at night and live in caves. They are notoriously elusive. The expedition team set up more than 80 cameras in the mountains and climbed the mountains every day to search. They even encountered earthquakes, and members also suffered accidents such as broken arms and malaria . But after four weeks of efforts, they still found nothing.

Temporary expedition camp on the northern slope of the Cyclops Mountains | Expedition Cyclops

Fortunately, hard work pays off. On the last day , in the video shot with the last memory card , an Attenborough long-beaked echidna suddenly appeared in front of the camera - three and a half years of careful planning and arduous expeditions finally paid off at this moment when the echidna passed by leisurely.

The discovery of the echidna was just one of the expedition's discoveries. They also conducted the first comprehensive survey of the animals of the Cyclops Mountains, discovering dozens of new insect species and a new type of land shrimp that lives under trees, mosses and even rocks and can jump to avoid predators.

Land shrimp found by Expedition Cyclops

Domestic sheep are not allowed to eat grass

In order to protect the bighorn sheep, domestic sheep have to move to other places to graze.

Recently, the National Wildlife Federation in the United States reached an agreement with ranchers: the Federation paid ranchers a large sum of money to allow them to avoid the habitat of bighorn sheep and let domestic sheep graze in other places . This money is enough for ranchers to lease private grasslands to graze domestic sheep and return public grasslands to bighorn sheep.

Bighorn sheep | Oregon Department of Fish & Wildlife / Wikimedia Commons

Bighorn sheep are known for their large, curly horns. More than a century ago, overhunting and diseases spread by livestock drove bighorn sheep to the brink of extinction in Colorado, U.S. The local government later reintroduced bighorn sheep, and their numbers have gradually rebounded to about 7,000. However, bighorn sheep still face their greatest threat: domestic sheep.

Public grasslands where domestic sheep graze often overlap with the habitat of bighorn sheep. Bighorn sheep are easily infected with diseases carried by domestic sheep , especially during the breeding season, when male bighorn sheep will look for mates and sometimes encounter domestic sheep and get pneumonia. When they return to their own group, the pathogen will quickly spread to their peers. Once a group of sheep is collectively infected with pneumonia, the death toll can even reach 90%, and the lambs born later will also be infected and die quickly within a month.

Bighorn Sheep Herd | California Department of Fish and Wildlife

Previously, in order to prevent the spread of diseases, if people found wild bighorn sheep mixed with domestic sheep or showed symptoms of pneumonia, they had to kill them. In 2015, people were forced to shoot an entire herd of bighorn sheep. The federation hopes that by allowing domestic sheep to graze in other places, bighorn sheep will no longer die from diseases and their numbers can gradually increase.

Chimpanzees scout each other

Chimpanzees scout each other for enemy intelligence and use that intelligence to inform military strategy, just as humans do.

A new study found that two neighboring western chimpanzee communities in Africa often clash over territory. Just like human armies, in order to monitor the enemy, they will send out "scouts" in batches to patrol the border of the territory, and will climb up the mountains and use the high terrain to keep a close eye on the movements of the other community. When in the mountains, chimpanzees will be surprisingly quiet , like a silent and alert army, listening carefully to sounds from all directions, and capturing the sounds of communication and actions of the enemy community.

Western Chimpanzee | Therabu / ZooChat

Many animals have the skill of monitoring predators from a commanding height and giving the alarm when they find danger. But chimpanzees are one step ahead. They will judge whether to advance or retreat based on the number and distance of the "enemy" - if the enemy chimpanzees are far away, they will advance into the enemy's territory and launch a surprise attack when the enemy is not prepared; if the enemy is large in number and very close, the reconnaissance troops will keep a low profile and retreat quickly. When leaving the reconnaissance point on the top of the mountain, they will also choose a route that avoids the enemy.

Western Chimpanzee | Liran Samuni / Tai Chimpanzee Project

Scientists believe that the open and covert fighting between chimpanzee groups can show that military strategy is not just a product of humans in the past few thousand years, but is rooted in our survival instinct in evolutionary history. This instinct allowed our ancestors to obtain more food and territorial resources and reproduce from generation to generation.

Starfish is all about the head

Scientists have been unsure where the starfish's head is, but recently they found the answer: starfish, almost their entire body is a head!

Starfish and other echinoderms have long been a mystery to science - their ancestors had bilaterally symmetrical body structures, but starfish have strangely evolved radial bodies with five or more arms growing from the center of the body.

Starfish | Atsme / Wikimedia Commons

Scientists have long debated where the starfish's head is: one hypothesis holds that the center of the starfish is the head, with the arms radiating outward from the trunk; the other holds that the base of the starfish belongs to the head, with the top being the back region of the body.

In a new study published in Nature, scientists overturned both hypotheses. They measured the gene expression of each part of the starfish's body and created a 3D model of the starfish's entire body mRNA. The results showed that genes related to the front of the body were expressed all the way to the end of the starfish's arms - that is, from the perspective of gene expression, almost the entire body of the starfish belongs to the head, and there is no torso. In essence, it is a head running around on the seabed.

Scientists study the bat starfish (Patiria miniata) | Björn S... / Wikimedia Commons

Scientists also discovered the secret of sea cucumbers. Although they look fat and seem to be a symmetrical structure with a head and a tail, their bodies are actually radial and have no trunk. We can imagine them as a long head lying on its side .

Wolves hunting sea otters

Wolves living along the Alaskan coast have learned to hunt sea otters.

Wolf with sea otter | Landon Bazeley / Kelsey Griffin

In 2016, a scientist first saw a wolf carrying a sea otter carcass, and in the following years, people saw similar scenes several times. But scientists are not sure whether the wolf caught the sea otter or just picked up the sea otter's carrion - after all, it is more common for wolves to eat ungulates such as deer, but they have never heard of them catching sea otters .

It wasn't until 2021 that three wolves were observed eating an adult sea otter and fresh blood was found at the scene , only then did people confirm that the sea otter was indeed killed by wolves.

Live footage of wolves killing seals | Kelsey Griffin

After further research, scientists recently discovered that due to the lack of sufficient terrestrial animals to eat, coastal wolves not only learned to catch sea otters, but also gained experience. They would wait until low tide to hunt, and specifically choose locations where sea otters often appear , which shows that they have a clear understanding of the tides and the whereabouts of their prey.

Coastal wolves have also developed a hunting strategy that is completely different from that of inland wolves - they can hunt alone , and a single wolf can kill large prey such as sea otters and harbor seals; whereas inland wolves often move out in groups, hunting ungulates together.

Mice can imagine

Is imagination unique to humans? In fact, mice also have the same imagination ability as humans.

A mouse moves on a spherical object surrounded by a panoramic VR screen | Chongxi Lai

Scientists have designed a series of VR games for laboratory mice. In the game "Jumper," inspired by the movie of the same name, scientists first trained mice to run to a goal post to receive a reward, and recorded the corresponding brain signals with electrodes. In the official game, they used a brain-computer interface to convert the brain activity of mice into action trajectories on the VR screen. The mice must imagine themselves running to the goal post, and the brain-computer interface receives brain signals corresponding to the action before they can get the reward - that is, they do not need to run, they only need to think about the route to the goal post to get the reward .

Don't look down on us rats! | AviationFreak / Wikimedia Commons

In the second game, Jedi Knight, a tribute to Star Wars, scientists tried to control the activity of the mice's hippocampus to make them imagine moving an object (rather than themselves) to a certain place - just like people lying in bed and imagining that the food in the refrigerator automatically moved to their hand.

The results of the experiment showed that mice performed very well, planning the route in their minds in just a few seconds , which was similar to the results of human experiments. This experiment proved that mice are not short-sighted, and their thoughts can transcend reality.

References

[1] https://phys.org/news/2023-11-bizarre-egg-laying-mammal-rediscovered-years.html

[2] https://phys.org/news/2023-11-domestic-sheep-longer-graze-swath.html

[3] https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002350

[4] https://www.nature.com/articles/s41586-023-06669-2

[5] https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.4185

[6] https://www.science.org/doi/10.1126/science.adh5206

Author: Cat Tun

Editor: Mai Mai