Sharks don't ride horses, but they can actually walk! | Nature Trumpet

Welcome to the 16th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth noting:

1) The little penguin put on his shoes and found his partner

2) A 200-year-old giant cactus fell

3) Rebellious killer whale teenagers, recently popular with vandalism

4) The beetle never forgets to carry bacteria on its back during its metamorphosis

5) Sharks can actually walk!

6) The dog burst into tears when he saw his owner

Penguin wearing shoes

Recently, a little penguin put on shoes !

Look at my new shoes | San Diego Zoo Wildlife Alliance

Lucas is a 4-year-old Spheniscus demersus penguin living in the San Diego Zoo in the United States. He suffers from bumblefoot, a chronic disease that causes swelling and pain in his feet . Moreover, due to his difficulty in moving, other penguins are reluctant to play with him.

The good news is that people have tailor-made orthopedic shoes for him. They first let Lucas walk on a piece of sand, and based on the footprints he left, they made a model of the shoe, then made the orthopedic shoe out of chloroprene and rubber, and added padding on the bottom. In order to be close to the natural foot color, they deliberately made the shoe black.

Lucas' life is much happier now that he has new shoes | San Diego Zoo Wildlife Alliance

With this new pair of shoes, Lucas' feet and ankles will be protected when he stands or walks, and the pressure on his feet will be less than before. Animal experts said that he has adapted to the shoes very well. Once he put on the shoes, his walking posture instantly became much more normal, and he can stagger to keep up with the other penguins. This undoubtedly increases his social opportunities - now, he even found a girlfriend !

Cactus collapse

A giant cactus that has lived for nearly 200 years collapsed recently due to heavy rain...

Fallen Giant Cactus | Arizona State Parks and Trails

This happened in Arizona, in the southwestern United States. Cactus is a symbol of the local desert . This cactus is called Carnegiea gigantea, one of the tallest cactus species. When full of water, the giant cactus can reach a height of about 10 meters and weigh more than 2 tons. The cactus that collapsed in the heavy rain was 12 meters high and had 34 "arms". Everyone called it "Strong-Arm".

House finch sitting on a saguaro fruit｜Quinn Dombrowski / Flickr

The giant cactus is very precious in the desert. Great horned owls build nests on it, and many other birds also use it as their home . The fall of "Strong Arm" may only be a loss of a magnificent landscape in the desert for people, but for many animals, they have lost a huge "motel".

Before Strongarm collapsed, it was home to many animals | Arizona State Parks and Trails

However, even if Strong Arm can no longer stand guard in the desert, it can still make use of its remaining energy. The local government plans to leave it where it fell. During the long decomposition process, Strong Arm can continue to provide food and habitat for various creatures , injecting new vitality into the surrounding desert.

It will be better if the killer whale grows bigger

Recently, off the coast of Europe, a group of killer whales broke the rudders of many ships.

Here we go, the protagonist! | H. Zell / Wikimedia Commons

The most recent incident happened off the coast of France: A father and daughter were sailing when they were suddenly surrounded by a group of killer whales. After 15 minutes, the killer whales sailed away, and only a quarter of the rudder was left on the sailboat. The father and daughter had no choice but to cancel their trip to Morocco and send the boat for repairs. Although no one was injured or killed, the killer whales' behavior has caused several boats to be damaged or even sunk.

A pod of young killer whales | Gillfoto / Wikimedia Commons

Even scientists can't explain why killer whales suddenly became interested in rudders. One researcher speculated that they might find the feeling of the boat's propeller pushing the water fun, so when the propeller stopped moving, they were unhappy and simply sabotaged it . Scientists also speculated that the killer whales that attacked the boat were likely male adolescents, who are usually curious and naughty , just like human teenagers in their rebellious period.

As for how to solve these frequent rudder breaking incidents - scientists can only say that it should be fine when the children grow up and mature...

A pod of killer whales in the North Pacific | Allen Shimada NOAA/NMFS/OST/AMD / Wikimedia Commons

This isn't the first time killer whales have done something weird like this. They live in groups, and like humans, they learn from each other and "follow trends." For example, in 1987, killer whales in Puget Sound began wearing dead salmon on their heads like hats ; within a few days, this "fashion" became popular among two other killer whale groups, and everyone wore salmon hats. However, the trend came and went quickly, and after about 6 weeks, no killer whales wore salmon as hats anymore. Recently, while killer whales in Europe are busy dismantling ship rudders , the most popular activity among killer whales in the Pacific is playing with crab pots .

Beetle back bacteria

During metamorphosis, a type of beetle "stuffs" its symbiotic bacteria into pockets on its back and carries them with it.

Analysis of the pupa of a pseudoleaf beetle using micro-CT. The three distinct storage pockets are shown in red. Reference [4]

This type of beetle belongs to the genus Lagria. When they are young, there are many symbiotic bacteria living on their bodies. They provide nutrition to the bacteria, and the bacteria help them defend against parasites . They can be said to be a good pair.

Beetles undergo metamorphosis as they grow and need to pupate before they can transform into adults. However, their symbiotic bacteria have lost the genes responsible for movement and cannot survive for long without the beetles. In order to ensure the survival of their bacterial partners during pupation, female beetles temporarily store their symbiotic bacteria in three special small pockets on their backs when they become pupae, and continue to provide nutrients for the bacteria.

Lagria villosa is the subject of this study. This is their larva, the stage before becoming a pupa. | RS Ranke

When the beetles reach adulthood, the symbiotic bacteria are moved out of the pockets and eventually take up residence in the glands of the female's reproductive system.

However, it seems that only female beetles make an effort to maintain a good relationship with the bacteria. In the pupae of male beetles, the pockets have degenerated, and the number of symbiotic bacteria inside is very small or even completely gone. Scientists believe that the main need of adults for symbiotic bacteria is to spread them to the next generation so that the bacteria can escort the growth of their offspring . But males do not lay eggs, so they no longer need to maintain a symbiotic relationship with the bacteria.

Adult Lagria villosa | RS Ranke

Walking shark

Oh my god, some sharks can actually "walk" !

At this time, a handsome spotted thresher shark (Hemiscyllium ocellatum) passed by｜Youtube: @NAture on PBS

The spotted thresher shark and several of its relatives have an astonishing ability to walk. The fish live in shallow waters of coral reefs, where oxygen levels often drop during low tides and water temperatures rise, which is a deadly threat to sharks. However, the spotted thresher shark can hold its breath for hours and tolerate rising temperatures - in critical moments, it can even walk .

On the reefs after low tide, people can see these strong little sharks walking on land and in the water. Relying on four paddle-shaped fins, they can roll and crawl nearly 30 meters until they find a suitable corner and stay there waiting for the tide to rise.

That's it - spotted thresher shark (Hemiscyllium ocellatum) | Citron / Wikimedia Commons

Scientists have also recently discovered that spotted thresher sharks change size as they grow, but not the way they move - unlike most animals.

Newly born spotted thresher sharks have a round belly with a large yolk sac inside, which provides them with nutrition for the next month until they can find food on their own. But whether it is a bloated baby shark or a juvenile shark without yolk, they walk and swim in exactly the same way . Why don't baby sharks adopt a gait that is more suitable for a spherical belly? This is the next question that scientists need to solve.

Dog crying

Dogs can literally shed tears of joy when reunited with their owners, according to a study published in Current Biology.

Image | Pixabay

The researchers recruited 20 dogs to participate in the experiment. When the dogs were separated from their owners for 5-7 hours, their eyes would be filled with tears (but they would not cry) ; however, when they saw familiar humans who were not their owners, there was no such change. The researchers believe that this change is caused by oxytocin , which is called the "love hormone" and is closely related to positive emotional connections. To verify this, they also used eye drops with oxytocin or placebo on the dogs - the results showed that oxytocin can indeed make the dogs produce more tears.

Although it is difficult for us to know what animals are thinking, physiological phenomena can help us better understand dogs' reactions. At the same time, the appearance of "tears in the eyes" will make dogs more popular with humans, making volunteers more willing to touch and care for them. Maybe "tears in the eyes" is also the "scheming" of puppy evolution.

References

[1]https://phys.org/news/2022-08-san-diego-zoo-penguin-orthopedic.html

[2]https://phys.org/news/2022-08-giant-year-old-cactus-toppled-heavy.html

[3]https://www.livescience.com/orcas-attacking-boats-europe

[4]Rebekka S. Janke et al, Morphological adaptation for ectosymbiont maintenance and transmission during metamorphosis in Lagria beetles, Frontiers in Physiology (2022). DOI: 10.3389/fphys.2022.979200

[5]https://academic.oup.com/icb/advance-article-abstract/doi/10.1093/icb/icac127/6650877?redirectedFrom=fulltext

[6]https://www.cell.com/current-biology/fulltext/S0960-9822(22)01132-0

Author: Maotun, Mai Mai

Editor: Mai Mai

The title picture comes from the Internet

This article comes from the Species Calendar, welcome to forward

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