Good morning!
It’s a good one for green monkeys anyway. Since coming from Africa on trading ships, green vervet monkeys have settled in well on the island of St. Kitts, so well that, “They’re everywhere,” laments island scientist Julien Chalifour. While they do monkey business, let’s read on about green lasers, black holes, and predator-prey antics.
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Giant penguin identified from beach fossils weighed as much as a gorilla |
Although large dinosaurs vanished from the planet 66 million years ago after the asteroid strike, they were not the last oversized creatures to walk the planet. To follow were giant tortoises, baleen whales, and giant ground sloths. Now, paleontologists add a new giant to the list with the discovery of the largest-ever penguin.
Just 5-10 million years after the dinosaur extinction (a blink of an eye in geologic time), Kumimanu fordycei waddled the shores of what is now New Zealand’s South Island. At 340 pounds, this black-bear-sized bird could have contributed to the spread of penguins to other parts of the world.
Says study author Daniel Ksepka, “Size conveys many advantages. A bigger penguin could capture larger prey, and more importantly it would have been better at conserving body temperature in cold waters.” K. fordycei shared the shores with a couple of smaller species, perhaps dividing the fish resources by size in “a crowded penguin environment.”
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Scientists find first evidence that supermassive black holes harbor dark energy |
Based on 9 billion years’ worth of data, space physicists think they may have found the illusive “dark energy.” Since data from the Hubble telescope in the late 1990s indicated that our universe is expanding ever faster, with objects getting pushed further from each other, this dark energy has been the culprit.
The mystery has been where dark energy — calculated to comprise 68% of the universe — resides. It was known that when stars die, the black holes at their centers continue to grow over time by sucking material in. But, in new study, researchers found that dark holes continue to gain mass that can only be explained as dark energy.
Says study author Chris Pearson, “At last we've got a solution for the origin of dark energy that's been perplexing cosmologists and theoretical physicists for more than 20 years.” The measured amount of dark energy in our universe can be accounted for by the energy inside the billions of black holes, which creates an anti-gravity vacuum that keeps our universe from collapsing!
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Cleaner wrasses can recognize their own faces in the mirror |
Gone are the days of humans having a monopoly on self-awareness. When Gordon Gallup created the “mirror test” in the 1960s, he couldn’t have predicted that other species would pass it with flying colors — first chimpanzees and some other primates, then dolphins and other whales, followed by elephants, magpies, and even a tiny fish.
Now, a new study shows how the tiny bluestreak cleaner wrasse (Labroides dimidiatus), puts its mirror test skills to work. Researchers monitored the responses of cleaner wrasses to photos —of themselves, of other cleaner wrasses, of their faces on other bodies, and of their bodies on other faces. After the mirror test, wrasses were less aggressive towards their photos of themselves and of their faces on other bodies, but not the other images, suggesting that facial self-recognition mediates the reaction.
Says study author Masanori Kohda, “Our study is the first to demonstrate that fish have an internal sense of self.” Further, he argues that “Since the target animal is a fish, this finding suggests that nearly all social vertebrates also have this higher sense of self,” a big claim that may get some narcissistic Homo sapiens riled up.
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If you’re a small fish and see a large, hungry fish approaching, how do you escape? That’s what researchers asked in a new study of predator evasion tactics of zebrafish larvae (Danio rerio). Would zebrafish larvae escape by fleeing straight away, by hiding like sand crabs, or by some other strategy like zigzagging as if chased by an elephant?
Using a large dataset from zebrafish larvae exposed to a robotic predator, researchers mapped their evasive responses. Explains study author Eva Kanso, "Instead of approaching the study with preconceived notions of what we think the animal is doing, we established a mathematical framework that would allow us to compare multiple theories in relation to data from experiments.”
The result? Larval zebrafish had the best chance of escape by fleeing perpendicular to the predator’s path, but can only afford it if they rapidly detected the predator. Indeed, another recent study showed that larval zebrafish are smart enough to slip around a barrier when chased by a predator. (See HERE.) But, whether a fish prey’s escape behavior is effective depends wholly on the predator’s hunting tactics.
Consider one of the fastest fishes in the world — the sailfish (Istiophorus spp.) — that hunts in groups by herding prey with their massive dorsal fins. Thanks to new high-tech sensors coupled with video, researchers captured a detailed view of how a sailfish hunted individually. It dove back and forth between the surface and the warm waters below, catching tuna by ascending straight up, fast.
And, while the sailfish has predator charisma — with its giant fin and high-speed swimming — there are other less showy predators that merit “top predator” status.
In the Arctic, a recent study found that sea stars are the equivalent of polar bears when it comes to the sediment food web. Granted, we don’t need to run from a sea star, but sea stars rank as one of the ocean’s most successful predators in their seafloor realm. The carnivorous diet of sea stars (Asteroidea) includes clams, mussels, and oysters, which they pry open using their suction-cupped arms.
“It’s a shift in our view of how the coastal Arctic marine food web works...wildlife inhabiting the seawater and those inhabiting the sediment form two distinct but interconnected subwebs,” says study author Rémi Amiraux. Clearly, predators and prey are all a matter of perspective. |
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Next time, we’ll analyze narcissism, psychopathy, and other personality disorders. |
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Written by Devin Reese, Edited by Jake Currie Copyright © 2021 Nerd Snacks, All rights reserved.
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