Why don't woodpeckers get concussions even though they peck so hard?

Welcome to the 13th issue of the Nature Trumpet column. In the past half month, we have collected these fun and interesting natural news and research:

1) Crucian carp hijacks sperm and gives birth to fatherless offspring

2) The baby elephant that fell into the pit was successfully rescued

3) A fish that looks like jelly and has its own suction cup

4) Fluorescent fish

5) Can woodpeckers get concussions?

6) 50,000 beluga whales live broadcast

Hijacking sperm

The silver carp, Europe's most successful invasive fish, has an unexpected method of reproduction - it "tricks" sperm and uses it to clone itself .

Female silver carp (Carassius gibelio) | Kuhl et al., 2022

Female silver crucians do not spend time looking for a suitable mate, they just need sperm - sperm can come from any other crucian carp species , such as different species of black crucian carp. To obtain sperm, female silver crucians will mix in a group of crucian carp and wait for sperm from other crucian carp.

But after the sperm and egg meet, they do not form a regular fertilized egg. Under the stimulation of sperm, the egg cell begins to divide by itself, breaking down the genetic material from the sperm at the same time, and the offspring produced in the end do not carry male genes at all. In other words, although sperm is needed, the child born by the female silver crucian carp has nothing to do with the "father of the child" . The sperm is just a tool for the egg cell to divide - this method of reproduction is called "sperm-dependent parthenogenesis."

Silver Carp: Needs objects, but not completely | Женя / Wikimedia Commons

The unique reproduction method of silver carp is attributed to hybridization between different species . Animals generally have only two sets of chromosomes, but silver carp has six sets, which is the result of hybridization with different species. Their genome has a total of 150 chromosomes, which is more than three times the human genome.

Scientists speculate that during the hybridization process, an accident occurred in meiosis, and the offspring eventually became polyploid. This coincidence made parthenogenesis possible and allowed the silver carp to expand rapidly, successfully occupying the habitat and food resources of the native crucian carp.

Baby elephant rescued

In Thailand, a poor baby elephant was rescued from a drainage ditch on a golf course .

The stadium is located in the suburbs, and a herd of elephants live nearby. The baby elephant fell into the drainage ditch and couldn't climb out. The mother elephant couldn't help and was so anxious that she kept walking around by the pit.

Fortunately, a passerby found the baby elephant and its anxious mother. In the pouring rain, veterinarians and rescuers rushed to the scene, but the mother elephant was afraid that people would hurt her child, so she stayed by the baby elephant and did not let the rescuers get close . In desperation, the veterinarian had to inject the mother elephant with three doses of sedatives . Unexpectedly, even though the mother elephant was about to lose consciousness, she still stumbled towards her child and finally fell into the pit , but she protected the baby elephant under her body.

The rescued mother elephant and the helpless baby elephant in the pit | References [2]

Rescuers used a truck crane to pull the mother elephant out of the pit and climbed on top of her to perform CPR while they used an excavator to clear the dirt in the pit to create a path for the baby elephant to climb out of the mud.

The baby elephant can finally crawl out! | References [2]

After more than three hours of rescue, the baby elephant was finally rescued from the drainage trough, and the mother elephant regained consciousness and fed the frightened baby elephant. Finally, their figures disappeared into the jungle together.

The mother elephant returned safely to the jungle with her baby | References [2]

Deep Sea Jelly

Recently, scientists discovered jellies in the sea of ​​Alaska...oh no, fish that look like jellies !

The round-spotted transparent lionfish looks like jelly and feels even more like jelly. | Sarah Friedman / NOAA

This fish, Crystallichthys cyclospilus, lives at depths of 100 to 800 meters underwater, so it is rarely known to the public. Not only does it look like jelly, it also feels very elastic - scientists believe that this is to maintain buoyancy and resist the pressure of the deep sea . Except for the eyes and stomach, their bodies are almost completely transparent , which allows them to blend into the dark background in the deep sea and become invisible to predators.

This lionfish also has a unique structure - a suction cup . The suction cup evolved from the pelvic fin, allowing them to attach to rocks and corals on the seabed and remain motionless in the water. At present, people only know that lionfish prey on small invertebrates, and their more characteristics need to be studied.

During this investigation, scientists also encountered many strange marine creatures: giant orange sea spiders with legs as long as supermodels ;

Orange sea spider | Sarah Friedman / NOAA

The miniature anglerfish has a ferocious big mouth filled with sharp teeth.

Anglerfish | Sarah Friedman / NOAA

Luminous fish

Irish researchers have discovered a new fluorescent organism: a larval roundfin fish (Cyclopterus lumpus) that glows green when stimulated by ultraviolet light.

Lumpfin larvae stimulated to glow | Thomas Juhasz-Dora

The researchers observed 11 90-day-old roundfin larvae under different light conditions. They were light green under natural light, but glowed bright green under ultraviolet light, with the strongest fluorescence at the raised nodules.

It is not yet clear what purpose this bright fluorescence serves for the lump-finned fish . Researchers speculate that bioluminescence may be a communication signal between these fish, and they may be able to recognize each other through fluorescence. It may also be related to attracting prey, or it may have no special purpose.

No fear of concussion

Why don't woodpeckers get concussions when they peck so hard? A common explanation in the past was that their skulls absorb the impact and protect their brains - but new research published in Current Biology suggests that this is not true .

High-speed photography of the North American black woodpecker (Dryocopus pileatus) | Current Biology / Van Wassenbergh et al.

In the past, people speculated that the "spongy" bone behind the woodpecker's upper beak and in front of the eye socket had a shock-absorbing effect. However, high-speed photography analysis showed that this structure was always very hard during the woodpecker's pecking process and had almost no shock-absorbing effect . The researchers also pointed out that the evolution of a skull that absorbs shock would reduce the efficiency of woodpeckers , which would also be detrimental to the survival of woodpeckers.

The green bones in this image were previously thought to help woodpeckers absorb shock, but they don't actually have that effect | Van Wassenbergh et al.

Although their skulls offer no protection, woodpeckers' brains are still safe—mainly because their brains are smaller and don't experience the same pressure changes as human brains at the same acceleration. The researchers calculated that the woodpeckers would have to peck twice as fast to cause a concussion.

White Whale Live

The sun is scorching, let’s take a look at the “cloud cooling” scene in the Arctic waters!

July 15 is Arctic Sea Ice Day , and a research vessel of the Arctic Conservation Organization has been broadcasting live the migration of beluga whales since this day. At this time of year, about 55,000 beluga whales migrate from the Arctic to Canada's Hudson Bay; when the bay is frozen in winter, they migrate north again.

Beluga whales migrating to Hudson Bay | Ansgar Walk / Wikimedia Commons

For beluga whales, Hudson Bay is a safe haven that allows them to escape from their predators, killer whales. Moreover, Hudson Bay is connected to the estuary of the Churchill River, which has abundant food resources, is warm, and has low salinity, which is very friendly to young beluga whales that do not grow enough blubber, and is also conducive to the molting of adult beluga whales.

The research vessel providing the live broadcast is named Delph, which is an abbreviation of the beluga whale's scientific name, Delphinapterus leucas. Delph has two camera positions, one on the deck and one below the water, which can also capture the various sounds of beluga whales , such as clicks, screams, and light snorts.

Beluga whale greets everyone via underwater camera | Madison Stevens / Polar Bears International

The live broadcast URL is here: https://polarbearsinternational.org/education-center/beluga-cams/

The live broadcast not only allows animal lovers to feast their eyes, but also provides researchers with valuable first-hand information. By observing the beluga whale population that migrates to Hudson Bay every year, researchers can confirm their health and reproduction status, and if there is any abnormality, they can formulate protection measures in time.

References

[1]https://phys.org/news/2022-07-invasive-fish-sperm-hijacking-success.html

[2]https://phys.org/news/2022-07-baby-elephant-thailand-manhole.html

[3]https://www.livescience.com/translucent-jell-o-fish

[4]https://onlinelibrary.wiley.com/doi/epdf/10.1111/jfb.15154

[5]https://www.cell.com/current-biology/fulltext/S0960-9822(22)00855-7

[6]https://www.livescience.com/beluga-cam-whales-migrate

Author: Cat Tun, Window Knocking Rain

Editor: Mai Mai

This article comes from the Species Calendar, welcome to forward

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