In order to survive, they can go without pooping for several months | Nature Trumpet

Welcome to the 67th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) In order not to pollute the water, tadpoles do not poop for several months

2) Overweight penguin chicks weigh more than their parents combined

3) Octopuses and fish cooperate in hunting, with clear division of labor

4) Wear a woolen hat to record your cat’s brain activity

5) Male locusts use their bodies as sunshades for females

6) Two injured comb jellies can merge into one

Tadpoles don't poop

In order to avoid polluting the water, tadpoles can go several months without pooping!

Ryukyu originally refers to the tadpoles of tree frogs that hatch and grow up in the accumulated water in tree holes.

This hidden small body of water protects them from predators, but it also brings a problem - the waste nitrogen in the tadpoles' bodies will be converted into toxic ammonia and excreted with feces, but the feces will accumulate in this small body of water , which may bring danger to them.

Tadpoles of the Ryukyu tree frog (Kurixalus eiffingeri) usually grow up in the water in tree holes. | References [1]

Therefore, tadpoles have evolved a unique skill of "storing feces". They keep feces in their intestines for several months until they reach the sub-adult stage, when they can metabolize the waste nitrogen compounds into non-toxic urea and then excrete them out of the body.

Their intestines are full of shit | References [1]

In addition to not pooping, the tadpoles of the Ryukyu tree frog have also evolved a higher tolerance to ammonia . Researchers raised them and tadpoles of other tree frog species in different concentrations of ammonium chloride solutions, and found that in the same high-ammonia environment, other tree frog tadpoles have died, but most of the tadpoles of the Ryukyu tree frog can survive; they will not die until the ammonia concentration in the environment increases further.

Overweight penguin chick

Whose penguin chick is heavier than its parents combined? !

Yes, it’s the biggest kiwi in the middle | Reference [2]

This is Pesto, a king penguin cub living in an aquarium in Australia. He has recently become the most popular penguin because of his size. This fat boy is only 9 months old, but he weighs 23.5 kilograms , almost as much as a gas tank; his parents weigh only 11 kilograms, and they are not as heavy as him when combined. Pesto's elders were also the heaviest penguins in the aquarium, which gave him a genetic advantage in weight.

Pesto stands with a medium-sized adult king penguin. | Bronwyn Thompson / New Atlas

Although he is the largest penguin in the aquarium at a young age, Pesto has no health problems caused by being overweight. He is healthy and confident , and gets along well with other penguins and keepers.

As can be seen from its body shape, it has a good appetite and eats nearly 30 fish every day. And because it is so greedy, weighing it has become a difficult task - it is always busy eating food rewards and is not willing to stand still on the scale.

Weighing Pesto, he is only two months old and already a small gas tank | Sea Life Melbourne Aquarium

In the wild, penguin chicks face predation from predatory birds. The smaller and weaker they are, the higher the risk of being eaten. In the wild, Pesto's size would be a huge advantage over penguin chicks - how would they catch such a large gas can? The skuas were also confused when they saw it.

As Pesto grows up, he will soon shed his current "kiwi" appearance and put on the "tuxedo" of an adult king penguin. This process consumes a lot of energy, and his appetite will also decrease, and he may lose some weight at that time .

Pesto's fur tastes like corn flakes, breeder reveals | USA TODAY

Octopus and fish cooperate to hunt

Just as humans hunt with hounds, octopuses hunt in partnership with fish.

The octopus in this study is the blue octopus (Octopus cyanea), which mainly eats fish, crabs, shrimp and mollusks | Ahmed Abdul Rahman / Wikimedia Commons

In a recent study, scientists analyzed 120 hours of underwater 3D data and found that octopuses and fish have a complex cooperative relationship, and they "read each other's eyes" when hunting. For example, the fish of the family of snappers will first search the environment and then inform the octopus where the prey is; the octopus will decide the most suitable hunting location and specific hunting strategy based on the information given by the fish. When the octopus catches the prey, the fish can eat together.

Interactions between octopuses and fish | References [3]

In such cooperation, fish are equivalent to scouts . They have a faster perception speed than octopuses and can efficiently detect a wider range of environments. Octopuses are combat experts in the team and can capture prey that many fish cannot catch. Scientists have found that when octopuses have reliable fish teammates around them, their hunting efficiency is much higher than groping alone.

When an octopus moves and explores its environment, it needs to do so slowly, not as fast as a fish. | References [3]

However, just like when working in a group, there will be bad teammates, not all fish can cooperate smoothly with octopuses . For example, red groupers are always waiting to eat but are unwilling to work hard. When they are present, the hunting efficiency of octopuses is no different from hunting alone; when octopuses and breams form a team (especially when red groupers are not present), the hunting efficiency is the highest.

The pig teammate who only eats but does not work - red grouper | Bernard DUPONT / Wikimedia Commons

Researchers have previously observed that fish appear near octopuses when they are hunting, but they thought that fish only came to get a bite of leftovers and did not participate in the hunting process. Now they have discovered that octopuses and fish not only have cross-species social abilities, but can also use social information to carry out complex cooperation and eat together.

Cat Beanie

To figure out what's going on in a cat's brain, researchers devised a secret weapon - a woolen hat!

Secret Weapon Beanie | Alienor Delsart

It looks like an ordinary woolen hat, but it actually has electrodes sewn into it to scan the cat's EEG . Cats often experience chronic pain due to various common diseases, and scanning the EEG can help assess the cat's stress and pain levels, which can help improve treatment options. However, if you put wired electrodes directly on the top of a cat's head, they will always shake the electrodes off and start chewing them, and humans can't do anything about it.

Cat: Forget it, let’s pet humans this time | Reference [4]

After the woolen hat version of the electrode was designed, scientists tested it on 11 adult cats with osteoarthritis. This time, humans successfully fooled the cats, recorded their EEGs while they were awake , and provided soothing smells and lights according to their pain conditions to relieve their pain.

Next, scientists plan to design an application that can automatically detect chronic pain. With a special woolen hat, cat owners can monitor their cats' stress and pain levels at home . Even if cats don't cry out in pain, humans can still tell if they are feeling unwell.

Cat is smelling a soothing scent | Reference [4]

Locust parasol

When female desert locusts lay eggs, the males become "tool insects" and serve as sunshades for their mates.

Desert locusts live in the desert and take several hours to lay eggs, so they usually lay eggs after sunset to avoid being exposed to extreme daytime heat. However, some females who delay laying eggs will start laying eggs the next morning, facing ground temperatures as high as 50°C.

A male Desert Locust (Schistocerca gregaria) riding on a female locust | Koutaro Ould Maeno / References [5]

Scientists recently discovered that during the day, 90% of female locusts are riding on a male locust, which looks like they are mating. But a closer look reveals that the females are actually laying eggs, and the males are acting as sunshades, helping to protect their spouses from the high temperatures while they lay their own offspring .

Male locusts act like parasols, helping females cool down in the hot sun | Koutaro Ould Maeno / References [5]

As a sunshade, the male locusts are very conscientious. They also change their position according to the position of the sun - when the sun moves in the sky, they will also move their position on the females in sync. Thermal imaging cameras show that the females with male locusts riding on their bodies have lower body temperatures than females fully exposed to the sun.

Desert locusts can cause major locust plagues around the world . They can form swarms of hundreds of millions of locusts, flying 100 to 200 kilometers a day. The food of at least one-tenth of the world's population is threatened by these locusts. Scientists believe that humans can take advantage of the period when female locusts lay eggs and male locusts act as sunshades, and use pesticides in a targeted manner to prevent locust plagues.

Locust plague | Magnus Ullman / Wikimedia Commons

Ctenophore Fusion

Science fiction has come true - two animals can actually become one!

This amazing animal is a freshwater comb jellyfish . Recently, scientists raised a group of comb jellies in the laboratory. One of the comb jellies was particularly large, and it had two organs at the top and back, as if two individuals were fused together. In order to verify this incredible speculation, they removed part of the brain lobes of the comb jellyfish and then put them together in pairs.

A fusion of two freshwater comb jellies (Mnemiopsis leidyi) | Mariana Rodriguez-Santiago

Then, something magical happened! After one night, the two injured individuals merged seamlessly, and even the nervous system was completely fused - when scientists poked one of the brain lobes, the entire fused body would react with a startle. Further research found that just two hours after the fusion, 95% of the muscles of the fused body would contract in complete sync, and when the muscles on one side were stimulated, the muscles on the other side would contract synchronously.

Two individual comb jellies | Petra Urbanek / Wikimedia Commons

After the two comb jellies merged, their digestive systems also merged . Scientists fed the fusion body food with fluorescent markers. When the food entered from one mouth, it would pass through the merged digestive tract, and finally the two anuses would discharge the food residue.

Fluorescently labeled food moves through the digestive tract of a fusion organism | References [6]

Scientists believe that comb jellies may not be able to recognize themselves and other members of their own species, which is why they merge so smoothly. Their mechanism of rapid merging and regenerating the nervous system can provide important inspiration for human neuroscience research.

References

[1] https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.4428

[2] https://phys.org/news/2024-09-hefty-australian-penguin-chick-pesto.html

[3] https://www.nature.com/articles/s41559-024-02525-2

[4] https://www.sciencedirect.com/science/article/pii/S0165027024001997

[5] https://esajournals.onlinelibrary.wiley.com/doi/10.1002/ecy.4416

[6] https://www.cell.com/current-biology/abstract/S0960-9822(24)01023-6

Author: Cat Tun

Editor: Mai Mai