These two male humpback whales, what are you doing | Nature Trumpet

Welcome to the 54th issue of the Nature Trumpet column. In the past half month, we have collected the following natural news and research worth reading:

1) Chernobyl's nematodes are immune to radiation

2) Two male humpback whales having sex

3) Asian elephants hold funerals after their calf dies

4) Gene mutation causes dogs to want to eat more

5) Giant pandas are brown and white because of a missing gene

6) Caterpillars eat toxins and use them as weapons

Chernobyl nematodes

In the place with the most serious nuclear radiation, there actually lives a kind of nematode that is not affected by radiation .

After the nuclear power plant accident in 1986, Chernobyl became a highly radioactive area. After the human retreat, many plants and animals still lived here, and most of them suffered genetic damage due to the effects of radiation. However, in a recent new study, scientists found an exception - a small nematode called Oscheius tipulae.

Nematodes collected from Chernobyl under a microscope | Sophia Tintori

Scientists sequenced the genome of nematodes living in Chernobyl and compared them with similar ones living around the world. They were surprised to find that the genome of nematodes collected from Chernobyl was not damaged by radiation . Further research found that some nematodes living in low-radiation environments were not easily damaged in their genes - this may be their innate skills, not the result of evolution in a high-radiation environment.

Researchers measuring radiation levels and collecting nematodes in the soil | Matthew Rockman

Scientists believe that this amazing little nematode may have special abilities to protect and repair genes , so using them as research subjects may explain why carcinogens have different effects on different people.

Same-sex sexual coercion in humpback whales

For the first time ever, researchers have documented sexual intercourse between two male humpback whales —and one of them appeared to be forced.

On-set photos | Lyle Krannichfeld and Brandi Romano

At first, a healthy and strong male humpback whale was chasing another male, who looked thin, had a bruised jaw, and was covered with parasitic whale lice. Unexpectedly, the strong whale chased and chased, and even exposed his genitals and began to force the weak whale . The victim whale did show signs of being stressed, with its body twisted into an S shape, but it was probably powerless to resist and could only try to slowly swim away.

The whale below is very weak and has a broken jaw, possibly from a collision with a boat | Lyle Krannichfeld and Brandi Romano

Although this is the first time that people have seen same-sex humpback whales mate, it is not uncommon among cetaceans. Bottlenose dolphins are the most likely to engage in same-sex sexual behavior . Studies have shown that sexual behavior between male dolphins can strengthen their alliance (Dolphins: If you are brothers, have sex!) and is a "rehearsal" for future mating with the opposite sex. Females occasionally engage in sexual behavior, but the probability is much smaller.

A Different Perspective | Lyle Krannichfeld and Brandi Romano

Researchers speculate that the powerful humpback whale may have mistaken the other whale for a female and thus acted in this way; it is also possible that it deliberately used coercive behavior against its weaker competitor to demonstrate its dominance.

Asian elephant funeral

If a baby elephant dies in the herd, Asian elephants will hold a grand funeral.

The first step of the funeral is to find a suitable cemetery. Indians have found that elephants have a special liking for human tea gardens because there are usually irrigation and drainage ditches there, so they don't need to dig their own cemeteries in the forest. In order to bury the baby elephants, adult elephants will not hesitate to carry the remains for a long distance, even for two full days, until they reach the cemetery .

Adult elephants carry the remains of their calves on a long journey to a cemetery | West Bengal Forest Department

A new study analyzed five funerals of Asian elephants and found that the herd seemed to have a set of ritual procedures. The five baby elephants were placed in the pit with their legs facing up, and the members of the herd would cover the bodies with mud and finally flatten the ground. Sometimes they would bury the baby elephant's head first, probably to prevent the baby elephant from being eaten by carnivores. After the baby elephant was buried, the herd would roar to express the pain and longing for the loss of their family .

The remains of an elephant calf buried upside down | West Bengal Forest Department

After the funeral, the memory of the baby elephant still affects the herd. From then on, the herd will deliberately avoid the road where the baby elephant was buried , even if this was the road they had to take every day. Researchers believe that the elephants may have associated this road with the death of the baby elephant, and in order to avoid bringing up sad memories, they will take a detour. These huge land animals also have emotions similar to humans.

Another Asian elephant calf buried | West Bengal Forest Department

Autopsies found that all of the buried elephants were one year old or younger and had died of natural causes due to illness. This is the first recorded burial of an Asian elephant ; before this, African forest elephants were observed covering their dead family members with branches.

Labrador genetic variation

Why do dogs at home eat so much and get excited when they see food? Don't blame them for being greedy, it may be in their genes!

A recent study found that a mutation in a gene called POMC makes some dogs more susceptible to obesity , including 25% of Labradors and 66% of flat-coated retrievers. The mutation makes them always hungry and have a lower metabolism - they eat more but burn less, which naturally makes them fat.

Eat, eat! Is it time to distribute food? | dmealiffe / Wikimedia Commons

Dogs with the gene mutation actually eat about the same amount of food as other dogs, but they get hungrier faster after eating.

Scientists recruited 87 dogs and fed them a can of food every 20 minutes. In the end, all the dogs ate a lot. The dogs with gene mutations and other dogs ate about the same amount of canned food. But three hours after feeding, the researchers took out sausages with the packaging cut a little to tempt the dogs, so that they could smell the taste but could not easily eat it. At this time, the dogs with gene mutations behaved particularly actively because they were hungrier and wanted to eat sausages more.

A Labrador trying to get a food reward | Divya Thakur / Wikimedia Commons

The POMC gene mutation changes the neural pathways of dogs, so that even if they already have enough food in their stomachs, the brain will continue to encourage them to find more food to eat . Some dogs have excellent patrol skills, perhaps because they are eager to get food rewards; while some dogs who open food bags and steal food are just trying to find ways to satisfy the brain's command to eat (forgive the children just once!).

The child hasn't eaten in five minutes! | Astro Boy/Wikimedia Commons

Giant panda gene mutation

Why are some giant pandas brown? It's not because the mother panda lost her ink while giving birth, but because of a genetic mutation !

Brown and white giant panda | AilieHM / Wikimedia Commons

There are several brown and white pandas living in the wild panda population of Qinling Mountains, and they have only appeared in this population so far. No one has figured out what caused their unique color until recently, when the research team of Academician Wei Fuwen of the Chinese Academy of Sciences found that the brown and white hair of pandas is related to the gene Bace2 . The two brown and white pandas they studied both had 25 base pairs missing in this gene.

Hair of black and white giant pandas and brown and white giant pandas | References [5]

For comparison, the researchers sequenced the genomes of 192 other black and white giant pandas and found that these giant pandas with normal fur color all had complete Bace2 genes. They also used Crispr-Cas9 technology to breed mice with the same gene locus missing. The results showed that normal mice are black, while these mice with gene deletions have lighter fur color , just like the difference between normal giant pandas and brown giant pandas.

The left side is a normal mouse, and the right side is a gene knockout mouse | Reference [5]

How does this gene mutation make giant pandas brown? Researchers have found that when the Bace2 gene loses base pairs, the size and number of melanosomes in the animal's hair decrease, reducing pigmentation and making the fur lighter.

Caterpillars eat toxins

Monarch butterfly caterpillars dare to eat even highly poisonous plants!

Caterpillar | Jim Hudgins / Wikimedia Commons

The mucus of milkweed contains toxins called cardenolides, which destroy the enzymes in the intestines that are responsible for the balance of sodium and potassium. Animals that eat them usually die. Monarch butterflies hatch their eggs into caterpillars on the leaves of milkweed. To avoid being poisoned, they avoid the white toxic mucus . Their feeding strategy is very clever - they bite through the veins of the leaves first to let the mucus out, and then dig in to eat the non-toxic part.

The white slime from milkweed is highly toxic | Ayotte Gilles / Wikimedia Commons

However, as the caterpillars grew up, they also became stronger and were no longer afraid of the toxins! They began to change their eating strategy and ate the highly toxic mucus directly, and nothing happened after eating it. The researchers extracted the toxic mucus and fed it directly to the caterpillars through a straw, and they also ate it like a kitten licking milk.

Researchers feed caterpillars toxic mucus through straws | References [6]

What is going on? Scientists have found that as caterpillars grow older, their bodies gain the ability to convert cardiolipin toxins into less toxic forms , so they are not killed by cardiolipin. Not only that, the toxins they eat remain in their bodies and become their own weapons to defend against predators.

Author: Cat Tun

Editor: Mai Mai

Image credit: Lyle Krannichfeld and Brandi Romano