Komodo dragons are now endangered and ‘moving toward extinction’
News and notes about science
The Komodo dragon has earned its status as a reptilian icon.
The carnivorous lizard can grow up to 10 feet long and is equipped with a forked tongue, serrated teeth, armored scales and venom-laced saliva. The dragons can detect flesh from miles away while hunting an impressive array of prey, including deer, boars, horses, water buffalo — and one another. Females are even known to eat their own offspring.
“It’s got this fearsome reputation,” said Craig Hilton-taylor, a biologist with the International Union for Conservation of Nature. “It’s like seeing your storybooks come alive.”
But now, the world’s largest living lizard has moved one step closer to being wiped out in the wild.
Komodo dragons, previously considered a “vulnerable” species, were reclassified recently as “endangered” by the conservation organization.
“It’s had a genuine change in status, a deterioration,” said Hilton-taylor, head of the international group’s Red List unit, which assesses the conservation risk of 138,000 species and counting. “It’s moving toward extinction.”
The new label is intended to spur international policymakers and conservation groups to strengthen and expand protections for the giant lizard in its natural habitats. That may be especially necessary among a population of the dragons that live in areas that are not protected and that are more vulnerable to activities such as illegal hunting and habitat clearance.
“It rings the alarm bells more loudly,” said Andrew Terry, a conservation director at the Zoological Society of London. “It increases the urgency to act.”
About 25 years ago, somewhere from 5,000 to 8,000 Komodo dragons roamed the Earth. Today, the IUCN estimates that there are just 1,380 adult Komodo dragons and another 2,000 juveniles left in the wild. “The real concern is what’s going to happen in the future,” Hilton-taylor said.
If Komodo dragons drop past a critically endangered status, they could become what’s known as “extinct in the wild,” and survive only in captivity. “I think that would be an awful indictment,” Terry said. “Nobody working in a zoo is happy to see a species only existing in a zoo.”
— Marion Renault
How the cat gets its stripes: it’s genetics, not a folk tale
Folklore is full of stories about the coat patterns of cats: How the tiger got its stripes. How the leopard got its spots. And scientists ask the same questions, although not necessarily about large predators. The research may focus instead on something like the mackerel tabby pattern in domestic shorthairs.
The question of how cat stripes and splotches are made touches on some of the deepest theoretical puzzles of biology. How does a blob of cells organize itself into a fruit fly, or a panda? What tells the bones in a limb to become a hand, or paw, or the ribbing of a leathery wing? What tells some skin cells to grow dark hair and others lighter hair?
A team of geneticists reported in the journal Nature Communications that it had identified a gene in domestic cats that plays a key role in creating the traditional tabby stripe pattern, and that the pattern is evident in embryonic tissue even before hair follicles start to grow.
The inheritance of cat coats — how to breed for this or that pattern — is well known. But how patterns emerge in a growing embryo “really has been an unsolved mystery,” said Dr. Gregory Barsh, an author of the new report.
“We think this is really the first glimpse into what the molecules might be” that are involved
in the process, he added.
The research team included Barsh, Christopher Kaelin and Dr. Kelly Mcgowan, all affiliated with the Hudsonalpha Institute for Biotechnology in Alabama and the Stanford University School of Medicine.
Barsh said the theoretical basis of the team’s work dated back to a groundbreaking paper by Alan Turing, famous for his work in computer science and code breaking. He wrote a paper called “The Chemical Basis of Morphogenesis” in 1952 that “really laid the groundwork for the entire field of mathematical biology,” Barsh said.
The paper describes what is called a reaction diffusion process in which two chemicals, one that stimulates gene activity and one that inhibits it, can result in regular, alternating patterns. Researchers have thought that this process could produce stripes in cat coats; Barsh said the team’s research had confirmed this.
Further, he said, the study shows for the first time that the gene Dkk4 and the protein it produces are central to the process. Dkk4 is the inhibitor in the process.
— James Gorman
‘Spaceship-shaped’ fossil reveals hungry predator of ancient oceans
Some 506 million years ago, a predator swept over the silt bottoms of the Cambrian ocean. Its rakelike feeding arms sifted through the murk it raised, funneling soft-bodied worms into a puckering, circular mouth.
In 2018, a team of paleontologists from the Royal Ontario Museum discovered the preserved shell of that ancient hunter during a fossil hunting expedition in the Canadian Rockies. In the journal Royal Society Open Science, the team identified the 19-inch animal, which they named Titanokorys gainesi, as one of the earliest-known large predators on Earth.
“At a time when most animals were the size of your little finger, this would have been a very large predator and probably near the top of the food chain,” said Joe Moysiuk, a PH.D. student at the University of Toronto and co-author of the study.
Over a half-billion years ago, the quiet gardens of the Ediacaran — largely full of soft-bodied organisms feeding on microbial mats — vanished. As the first predatory animals evolved, ecosystems grew more complex and many of the major animal groups that still live today appeared for the first time: a geological turnover called the “Cambrian explosion.”
In 1909, the first evidence of this change was uncovered in the Burgess Shale of the Canadian Rockies. Researchers studying fine-grained sediments there found the soft-bodied imprints of a wild — if tiny — menagerie.
The primary carnivores of this ecosystem were a family of arthropods called radiodonts, named for their toothy, circular jaws. The largest and most iconic of the family, Anomalocaris, was a 3-foot apex predator, with a streamlined body and fluttering paddles that helped it zip through open water.
For decades, Anomalocaris was the only large predator known from the Burgess Shale, said Jean-bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum. But in 2014, as he and colleagues were collecting in Kootenay National Park in British Columbia, they began finding scraps of a mysterious new animal. Four years later, a complete carapace “the size of a football helmet” turned up.
Though related to Anomalocaris, Titanokorys was a different kind of hunter. While it shared the lobed swimming paddles of its larger relative, its broad head carapace took up half its body length. It had jointed claws and rear-set, upward-facing eyes. It probably lived like a modern stingray or horseshoe crab, hoovering up prey from the silty bottom.
— Asher Elbein
How math solved the case of the volcanic bombs that didn’t explode
It would be reasonable to hear the term “volcanic bomb” and presuppose that such an object tends to explode. But a specific type of volcanic bomb rarely lives up to the second half of its name. These objects get blasted into the air, crash into the ground and disappointingly fail to detonate.
These volcanic bombs — plasticky, partly molten blisters of magma no smaller than a peach — are shot out of a volcano submerged by a shallow body of water, like a lake or the sea close to shore. In the process, the bombs acquire plenty of water. That trapped water encounters the bomb’s scorching-hot innards and gets vigorously boiled into steam.
The sudden accumulation of steam within the projectile should blast the bomb apart in midair. “Rocks cannot survive in the face of that pressure,” said Mark Mcguinness, a mathematician at Victoria University of Wellington in New Zealand.
Solving this riddle would do more than scratch a long-standing scientific itch. Volcanic bombs, a fundamental part of many explosive eruptions, are also a lethal hazard. If more of them blew up midflight, that would be preferable to their clonking someone on the head.
Wishing to crack the case, Ian Schipper, a volcanologist at Victoria, joined forces with Mcguinness and Emma Greenbank, also a mathematician at the university. They built a mathematical model that simulated the launch of a bomb from a virtual volcano and replicated the changing pressures and temperatures of the orb’s insides.
Reporting their results in The Proceedings of the Royal Society A, the team concludes that water both makes and defuses these doughy volcanic bombs.
As magma rises through a volcano and toward the surface, it depressurizes, and the water imprisoned inside it escapes as a vapor, creating bubbles. That clump of foamy magma then gets launched through the water and becomes a bomb. The lake or seawater that then infiltrates the bomb violently boils off. But the team’s mathematical simulations show that the bomb’s already foamy nature means there are myriad pathways that the steam can flow through and escape, thus stopping a pressure spike and, ultimately, an explosion.
A few bombs, those lacking a foamy network of holes created by the magma’s own water, will succumb to the pressure of the newly generated steam and self-destruct. But most are sufficiently frothy, allowing the steam to evacuate without incident.