Dogs, don’t stay idle at home, take online classes | Nature Trumpet

Welcome to the 58th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) The killer whale attacked again and the ship was sunk

2) Tiger beetles use ultrasound to impersonate moths

3) Enzymes from fruit fly testicles, a new method for killing mosquitoes

4) The sea lions held a meeting, it was so crowded

5) Elephant meet and greet

6) Dogs can really take online classes

Killer whale sinks ship again

Recently, killer whales sank another ship.

This happened in the Moroccan waters of the Strait of Gibraltar. There were two people on the boat at the time. When they found the killer whale attacking the hull and rudder, they quickly sent a message to the rescue department. Fortunately, a nearby oil tanker came over immediately and rescued the two people, and the attacked ship eventually sank.

Three killer whales repeatedly rammed their heads against the oars of a race boat in June 2023 | The Ocean Race

Since May 2020, a group of killer whales seem to have become interested in human ships, and from time to time they gather to destroy passing ships. So far, there have been nearly 700 attacks , and several ships have suffered huge damage. However, killer whales are only interested in ships and will not attack people, so no humans have been harmed so far .

Researchers have not yet figured out why killer whales attack ships, and they have speculated on two possible reasons. One possibility is that this is just a new form of game that has become popular among killer whales in recent years, just like the southern killer whale group once became popular with salmon as hats. Another possible reason is that killer whales launched "revenge" on ships out of self-protection - there are countless incidents of whales being injured or killed by ships. At first, it may be that whales injured by ships began to attack ships, and over time, the younger generation began to follow suit.

The same group of killer whales damaged a passing boat in 2021 | Stefan George Kudor / YouTube

Renaud de Stephanis, a whale expert, supports the latter hypothesis. In the 1990s, he found that a group of killer whales began to steal fish from tuna fishing boats and taught this skill to the next generation. At that time, due to overfishing by humans, killer whales had less prey, so this could be considered a self-protective action. The killer whales that have started attacking ships in recent years are the same group that stole tuna back then.

Tiger beetle pretending to be a moth

To avoid being preyed upon by bats, some tiger beetles have a clever trick - using ultrasound to camouflage themselves.

Tiger beetles are found all over the world, with more than 2,000 species known | Jeevan Jose / Wikimedia Commons

Bats emit ultrasonic pulses from time to time when flying, and use echoes to retrieve the environment and locate prey. Scientists have found that when some tiger beetle species are played with bat ultrasonic waves, the tiger beetles will respond by swinging their elytra backwards so that the elytra and hind wings collide. To our human ears, the tiger beetle's response is just some unnoticeable buzzing; but to the ears of bats, such sounds are loud and clear.

Some tiger beetles have defensive chemicals such as benzaldehyde, so scientists speculate that they are using ultrasound to warn bats, "I am poisonous, don't eat me." To verify this conjecture, they fed tiger beetles to big brown bats and found that the defensive chemicals of tiger beetles had almost no effect on big brown bats . Not only were the big brown bats not poisoned, they even ate them with relish.

A big brown bat fed mealworms | USFS / Sandy Frost

Scientists thought of another possibility: tiger beetles may be using ultrasound to imitate tiger moths, a poisonous moth that bats actually avoid. The researchers compared the ultrasounds of tiger beetles and tiger moths and found a clear overlap. It turns out that the buzzing of tiger beetles is a kind of acoustic mimicry . When bats hear such sounds after emitting ultrasound, they think it is a poisonous prey that needs to be avoided, and the tiger beetles can escape.

Drosophila testis enzyme

Recently, scientists have found a good way to kill mosquitoes from the testicles of fruit flies.

Male fruit fly | André Karwath aka Aka / Wikimedia Commons

The key lies in an enzyme in the fruit fly testes that is responsible for inhibiting the expression of bromotyrosine. Bromotyrosine is a natural variation of the common amino acid tyrosine, which is naturally produced in insects. As long as their number is within the normal range, it will not have any effect on the body. But scientists unexpectedly discovered that if the enzyme that inhibits the expression of bromotyrosine no longer works, bromotyrosine accumulates in the body, and the fruit fly's ability to produce sperm will be affected, greatly reducing their fertility .

If this enzyme is inhibited, fruit flies will not be able to reproduce normally, so can this method also be used to control pests? Scientists also thought of this and decided to start with mosquitoes.

Damn mosquitoes | James Gathany, USCDCP / Wikimedia Commons

A common method of killing mosquitoes is to use sugar water or fruit juice as bait, and mix it with substances that are toxic to mosquitoes. The mosquitoes can live a few more days at best, or die on the spot at worst. They plan to add bromotyrosine and substances that inhibit enzyme expression to the mosquitoes' luxury lunch to kill mosquitoes more effectively - even if the mosquitoes don't die on the spot, they can be happy to have no offspring.

If substances that inhibit this enzyme are added to mosquito repellents, will it have an impact on humans? The good news is that although human testicles have enzymes with similar functions, they are different from the enzymes in insects, and human fertility will not be affected.

Sea Lion Convention

The sea lions are having a meeting!

If you recently visited Pier 39, a tourist attraction in San Francisco, you would have seen sea lions lying flat on the ground. This year, due to the increase in fish nearby, there were about 1,100 to 1,200 sea lions here, making it the largest sea lion convention in 15 years .

Yes, there are piles of sea lions | Godofredo A. Vásquez / AP

There are floating rafts specially prepared for sea lions on the pier, and they lie on them in all directions. Their poop will pile up on the rafts, so someone is responsible for cleaning them every week to prevent them from being drowned in poop. However, there are too many sea lions recently! The staff at the pier said that their cleaning work had to be suspended because moving the rafts around in the crowd would only cause chaos.

It was so crowded, but everyone slept soundly | Godofredo A. Vásquez / AP

Pier 39 is a resting place and gas station for sea lions during their migration. Here, they don't have to worry about being chased by killer whales and sharks. They can lie down lazily and let the sun wrap around their plump bodies. When they are hungry, they will eat a big meal of anchovies, and then continue to lie on the beach until their bodies are covered with fat that is about to overflow. In June, the well-fed sea lions will be called by love and set off again to the breeding site.

You need to have enough fat on your body before you can fall in love | ANADOLU AGENCY

For the locals, sea lions are like their patron saints. In 1989, a major earthquake occurred in the area, killing more than 60 people. Tourists began to avoid this place, and everyone lost business. Until the sea lions arrived in groups, tourists came again to see the grand scene of the sea lions meeting.

Elephant gesturing

Elephants also greet each other when they meet, and use gestures just like humans - to be precise, using their ears and trunks.

Elephant: My trunk has more functions than yours | keithlawson / Wikimedia Commons

In a new study, scientists decided to conduct an experiment on semi-wild elephants in Zimbabwe in order to find out how elephants usually greet each other. Elephants only like to greet friends with whom they have a good relationship . The first step for scientists was to find out who plays well with whom. According to the advice of the keepers, they used the "close" rule - observing twice a month to see which elephants always stand closest to each other. Among the 9 elephants, they finally selected the 6 elephants with the closest relationship.

Q: Who has the best relationship in this picture? | Dietmar Rabich / Wikimedia Commons

They separated the elephants for 10 minutes each time, then reunited them to observe what actions they would take when they met again. It turned out that elephants would perform some obvious and meaningful behaviors when they met. For example, their most common greetings were flapping their ears, waving their trunks, and lifting their tails, accompanied by rumbling sounds . Moreover, just as humans always nod and greet each other after making eye contact when meeting acquaintances, elephants often make eye contact before following the greeting process.

Researchers discover elephants' greeting method | References [5]

Elephants don't even need to meet to communicate. There are no cell phones in the elephant world, but they do have a unique way to communicate over long distances - low rumbling sounds. Their sounds are too low-frequency for us humans to hear, but their companions can hear them from many kilometers away.

Dog online lessons

Dogs, don’t stay idle at home, come and take online classes! (Not

Dog: Do not disturb, I am taking an online class | References [6]

Recently, scientists have discovered that dogs really have the potential to take online classes - they can imitate human actions through videos . They found a golden retriever and a Labrador and separated them from their owners into different rooms. The dogs can see their owners through the projection of the online video conference and can interact with them in real time. At this time, the owner will make a set of movements, and the dog's task is to imitate the owner.

Before each test, the owner would demonstrate the action to the dog using an online video and then prompt them to "Do it!" Surprisingly, the dog successfully imitated walking backwards, turning around, pressing buttons, and lying down, and even completed more difficult actions such as picking up objects and touching a pole with its nose .

There's nothing our puppies can't learn! | Batten, Barton, Durstine & Osborn / Wikimedia Commons

Scientists put three different camera angles for their owners: front, side, and top-down. Dogs can perfectly imitate the movements observed from the front and side angles , but if the video angle is from a top-down angle, the dog's brain crashes! This is because dogs are most familiar with the front and side angles when they usually get along with their owners, and looking down is a bit difficult for them because of their height.

No? This is how we normally look at people! ? Who has ever seen the top of a head! | Mcitsci / Wikimedia Commons

Author: Cat Tun

Editor: Mai Mai