A shark "mummy" was found in an abandoned aquarium!

In the past half month, we have collected these interesting contents: fish wearing "rose veils"; shark "mummies" that look like zombies; sharks can sleep with their eyes open; the little bonobo is "jealous" because of the second baby; 1,000 spiders hunt together; small nematodes can also make complex decisions.

Fish with a "rose veil"

Have you ever seen a fish that looks as beautiful as a flower?

New fish species named Cirrhilabrus finifenmaa | YI-KAI TEA

This "colorful" fish is a new local fish species discovered by Maldivian scientists. It was named "Cirrhilabrus finifenmaa", which translates to "rose veil fairy fish"; "finifenmaa" means "rose" in the local Dhivehi language, and the national flower of the Maldives is rose.

Sharks that can sleep with their eyes open

For most animals, spending long periods of time with their eyes closed means sleep — but sharks can sleep with their eyes open!

The true shadow wool shark (Cephaloscyllium isabellum) sometimes stops and stays in the same position. Australian researchers measured the metabolic rate and found that when the sharks stopped to rest, their oxygen consumption was greatly reduced and their bodies entered a low-energy mode, which means they fell asleep. But the interesting thing is that sharks do not necessarily close their eyes when they stop - that is, they can sleep with their eyes open.

A true-shadow woolly shark napping with its eyes open underwater | Victorgrigas / Wikimedia Commons

Whether sharks close their eyes when sleeping depends on the light in the environment. If they take a nap during the day when there is enough light, they will close their eyes; if they sleep at night, they will open their eyes 38% of the time.

Sharks (Atelomycterus marmoratus): Sitting in a row, sleeping | Lakshmi Sawitri / Wikimedia Commons

Previously, people believed that the true shadow wool shark was a nocturnal animal, resting during the day and moving at night. However, this study shows that they actually take naps regardless of day or night, but at night, they may sleep with their eyes open.

The Jealous Bonobos

When a mother gives birth to her second or third child, the older child becomes very anxious, fearing that his or her younger siblings will take away their mother's love and affection - this mentality is not only present in human babies, but also in baby bonobos!

25-year-old bonobo mother and 2-year-old baby | WH Calvin Diego Zoo / Wikimedia Commons

What happens to the little bonobos when their siblings are born? Scientists measured changes in their various physical indicators and found that their cortisol levels increased fivefold, a sign of a sharp increase in stress levels. This high-stress state will last up to seven months, and their immunity will also decrease. Moreover, no matter how old the little bonobos are, as long as they have brothers and sisters, their stress levels are equally high.

This is an unexpected finding. In previous studies, captive bonobos had only twice the normal level of cortisol when facing stress tests; in the natural environment, when wild chimpanzees encounter another group and face a potentially lethal fight, their cortisol levels are 1.5 times higher than normal. Compared to these situations, the little bonobo with a 5-fold increase in cortisol levels is extremely anxious about the arrival of a younger brother or sister!

Baby bonobo | Fanny Schertzer / Wikimedia Commons

Scientists believe that this stress response may be related to the social environment of young bonobos. When they have younger brothers and sisters, their mothers have more attention and give them less support and care. The older ones also face threats from their own kind - young bonobos are easily attacked by adult males, and the probability of being attacked increases with age.

Shark "Mummy"

A 'mummy' shark that looks like a zombie has been found in an abandoned aquarium in Spain.

Reef Shark "Mummy" | Juj' Urbex

When a pair of "urban explorers" broke into this unknown aquarium, they saw the rotting remains of a reef shark. It was placed in a broken glass box. Judging from the size of the glass box, it was dead when it was originally displayed and was preserved by chemical treatment. Later, the glass box was destroyed and the shark began to rot, eventually becoming a horror movie-like appearance.

The photographer revealed that the aquarium was closed after being hit by huge waves in 2014. In addition to zombie sharks, they also found the remains of octopuses, squids, starfish and other animals here.

Spider's Hunt

A spider-phobe's worst nightmare has come true - hundreds of spiders hunting together!

Spiders are usually solitary, but of the approximately 50,000 known species, 10 live in groups. One species, Anelosimus eximius, lives in huge colonies of up to 1,000 individuals, working together to weave meters-long webs and hunt together.

Social spider Anelosimus eximius | Bernard DUPONT / Wikimedia Commons

When spiders attack together, they can catch much larger prey than when they hunt alone. But how do hundreds or thousands of spiders organize an attack?

Together they weave a giant web that is 5 meters long and 3 meters high | Bertrand Krafft, Laurie J. Cookson / Wikimedia Commons

Researchers have found that they do not have a leader, and rely entirely on the vibration of the spider web to coordinate their actions. When a prey accidentally falls into the web, its struggle will cause the spider web to tremble, and the spiders scattered everywhere will rush to the prey together. However, when so many spiders crawl together, the spider web will also vibrate, and the spiders that are halfway through will not be able to sense the location of the prey.

So they adopted a "walk and stop" method - first rush forward together, then stop at the same time, feel the vibration from the prey itself, re-confirm its position, and then repeat the process. When all companions gather around the prey, they will attack together and enjoy this feast together.

Small nematode, great wisdom

Even a tiny nematode that is only 1 mm long knows how to look at what people are doing to it.

A predatory nematode named Pristionchus pacificus is a competitor of the common laboratory animal Caenorhabditis elegans. They both love to eat bacteria, and when competing for food, the predatory nematode will kill or bite the Caenorhabditis elegans, take the bacteria for itself, and sometimes even eat the Caenorhabditis elegans. However, the predatory nematode has its own judgment on whether to kill or bite its opponent.

After being bitten by a predatory nematode on the left, the Caenorhabditis elegans on the right flees | Salk Institute

When this predatory nematode encounters a larva of C. elegans, it is more likely to kill and eat it; when it encounters an adult, it tends to bite the other party and keep them away from its territory - although the predatory nematode has the ability to kill the adult, it takes more energy and there is a risk of injury. They will judge whether it is worthwhile to spend energy to kill the other party based on the size, life stage and current situation of the other party.

Humans have hundreds of millions of neurons, but this tiny nematode has only 300. People might think that such a small creature must be simple-minded, but this study has brought an unexpected discovery: tiny nematodes can also judge the situation and make the most beneficial decision for themselves.

References

[1]https://zookeys.pensoft.net/article/78139/

[2]https://www.livescience.com/sharks-sleep-with-eyes-open

[3]https://www.biorxiv.org/content/10.1101/2022.02.14.480345v1.abstract

[4]https://www.livescience.com/zombie-shark-found-in-abandoned-aquarium

[5]https://www.livescience.com/social-spiders-hunt-in-packs

[6]https://www.livescience.com/worms-make-complex-decisions-with-300-neurons

Author: Cat Tun

Editor: Mai Mai

This article comes from the Species Calendar, welcome to forward

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