Good morning!
Someone on an errant rewilding mission keeps releasing animals from the Dallas Zoo, including two emperor tamarin monkeys just recovered. Given the string of animal escapes from slashed enclosures, there’s a $25,000 reward for information on the monkey snatcher. Meanwhile, read about hell pigs, stellar bars, and regeneration.
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An iceberg the size of greater London has just left home, calving from Antarctica’s Brunt Ice Shelf. Satellite data showed the 1550-km-sq chunk leaving the mother berg behind, evidenced by a north-south chasm between them. The good news is that “It’s a natural event; it’s not linked to climate change,” says glaciologist Dominic Hodgson. But each iceberg calving speeds up the flow of ice off the parent ice shelf. Headed for an empty nest?!
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Turns out "hell pigs" aren't fierce predators after all |
Hell Pigs earned their name from perceptions of their terrifying biology. With shoulders nearly 6 feet tall, skulls as long as 3 feet, and jaws full of heavy teeth, it’s no wonder. These entelodonts (scientific name) — widespread from about 50 million years ago until their extinction 16 million years ago — were previously pegged as bone chompers with powerful bites.
Now, a new study of their teeth reveals that entolodonts might not have been so scary after all, except to their species. Researchers analyzed the microscopic wear on teeth of Entelodon magnus, and concluded that its diet was comparable to the diet of a wild boar, an animal that also looks intimidating but mostly eats roots, fruits, and nuts, adding small animals or carrion when available.
So, what’s with the giant canines? Says study author Florent Rivals, “We can discard the carnivore behavior,” explaining that they likely instead used their toothy mouths for male rivalry. Like their cousins the hippos today, entelodont males may have clashed open-mouthed with their exceptional gapes, leaving wounds on each other’s heads. Still sort of scary.
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Male marsupial quolls mate themselves to death |
Although humans view courtship as romantic, for many animals it spells the beginning of the end. Male honeybees die when their rear ends get ripped off after mating. Male octopuses stagger around and starve themselves, with females not far behind after egg brooding. And the demanding journey upstream leaves most male and female salmon ready to kick the bucket.
But a mammal, really? A recent study of Australian northern quolls (Dasyurus hallucatus) examined why males die after one mating season. Their randiness motivates male quolls to mate so much that they suffer from poor nutrition and related health problems. “Their drive is so strong that they forgo sleeping to spend more time searching for females,” says study author Christofer Clemente. Then, they get killed by predators or mere exhaustion.
Scientists are concerned that this strategy of semelparity (concentrating all reproductive investment in one breeding season), which for mammals occurs only in quolls and related marsupials (and some college students), could hasten their demise. Northern quolls are endangered, and losing the cohort of breeding males every season won’t help them recover.
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James Webb spots stellar bars in galaxies like our Milky Way |
Stellar Bar sounds like a new candy, and for some inexplicable reason is a sink brand name, but is most significantly a cluster of stars that move together and drive galaxy evolution. Stellar bars channel gases into the middle of galaxies, where it becomes new stars.
In a new study not yet published, researchers observed stellar bars in 11-billion-year-old galaxies, thanks to the high resolution of NASA’s JWST images. Says study author Shardha Jogee, “Just like we need to bring raw material from the harbor to inland factories that make new products, a bar powerfully transports gas into the central region where the gas is rapidly converted into new stars at a rate typically 10 to 100 times faster than in the rest of the galaxy.”
Stellar bars are the engines for galaxy evolution, not only by fostering star production, but also by fostering supermassive black holes at the centers of galaxies, like Sagittarius A* in our Milky Way. Now that we can observe bars in younger galaxies, we can learn more about how galaxies form over billions of years. |
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A starfish creeps over a reef, looking for tasty oysters, until…suspense sound…a sea turtle eats it up. Wait, no, rewind…A starfish creeps over a reef, looking for tasty oysters, until…less dramatic suspense sound…a sea turtle bites just the leg while the rest of the starfish escapes. Although the starfish is now minus a leg, it has evaded death and will gradually regenerate the limb.
Odder still is that a severed limb can regenerate an entire starfish, including its nerves. A 2022 study probes the process of regenerating a functional network of nerve cells.
“If we know what lies within starfish that allows them to regrow whole new bodies from limbs, we can compare that with what is in the cells and genes of human to see what is similar and different,” says study author Veronica Hinman. The researchers beheaded larval starfish (positively medieval) and found that through expression of a certain gene (sox2), injured starfish nerve cells reentered the process of original development from embryo to starfish.
While starfish have been poster children for regeneration, a recent study positions sea spiders as rivals. Because they molt their hard exoskeletons as they grow, spiders and other arthropods were previously thought incapable of regeneration other than of legs. But the researchers lopped various body parts off juvenile and adult sea spiders (again, medieval), and were surprised to find that a juvenile spider could regenerate muscles, reproductive parts, the hindgut, and even the anus.
Says study author Gerhard Scholtz, “Nobody had expected this.” None of the adults regenerated these parts, suggesting that the ability switches off at some point.
Vertebrates have the most limited regeneration abilities. Some lizards can let their tails go (tail autotomy), which — like starfish legs — may facilitate an escape from a predator. (See HERE how a lizard’s tail detaches at a weak point and then continues wiggling, presumably to draw a predator’s attention away from the rest of the lizard.) A lizard can’t afford to lose its head — like the larval starfish — or its vital organs — like the sea spider, because they won’t regenerate.
Still, behind research on regeneration is the hope that by decoding how it works at a molecular level (like expression of the sox2 gene in starfish), it can be somehow applied to human limb regeneration. Imagine the joy of the 185,000 people in U.S. alone who lose limbs to be able to grow new ones.
In a step forward for vertebrates, a 2022 study discovered reported on a molecule (M1) that stimulates nerve regeneration in the optic nerves of mice. Study author Eddie Ma Chi-him celebrates that “Regenerated axons elicit neural activities in target brain regions and restore visual functions after M1 treatment,” i.e., the mouse brains responded to visual stimuli again.
While there’s a long way to go from this discovery to therapeutic restoration of full optic nerve function in humans, the research moves us one step closer to starfish stardom. |
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Next time, we’ll see what bears are up to. |
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Written by Devin Reese, Edited by Jake Currie Copyright © 2021 Nerd Snacks, All rights reserved.
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