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It’s not just extinction: meet defaunation

Get ready to learn a new word: defaunation. Fauna is the total collection of animals—both in terms of species diversity and abundance—in a given area. So, defaunation, much like deforestation, means the loss of animals in all its myriad forms, including extinction, extirpation, or population declines. A special issue in Science today shines light on this little-discussed global trend and highlights how it’s impacting human society.
"Though for emotional or aesthetic reasons we may lament the loss of large charismatic species, such as tigers, rhinos, and pandas, we now know that loss of animals, from the largest elephant to the smallest beetle, will also fundamentally alter the form and function of the ecosystems upon which we all depend," writes Sacha Vignieri, an Associate Editor with Science in an introduction on the issue.
Starting with the bigger—more well-known—species, vertebrate populations on average have declined by over a quarter in the last forty years, according to a review paper in the issue. Such numbers are borne out by a lot of anecdotal reporting of the “empty forest” syndrome, where scientists are noticing more-and-more seemingly intact forests and other habitats that have been stripped of their medium to large vertebrates.
Meanwhile at least 322 vertebrates have gone extinct since 1500, a trend in human-caused extinctions that likely began during the Pleistocene. Many additional vertebrates remain unrecorded for decades and could be extinct.
But “fauna” also extends to invertebrates, which really comprise the vast bulk of the world’s animals. Most of these animals—which includes everything from insects to mollusks and jellyfish to spiders—have been far less studied than the world’s vertebrates and so much less is known about how imperiled they are and their population trends. Still, the data that we do have is not good.
A global review of 452 invertebrates find that these populations have fallen by 45 percent over the last 40 years. The best data is in the Lepidoptera family—moths and butterflies—which shows a drop in abundance of about 35 percent.

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Colugos are little-known, forest-dwelling animals that have huge gliding membranes, similar to flying squirrels. This enables them to make spectacular leaps from tree to tree.
Baby colugos are born tiny and helpless, and are carried on the mother’s belly for six months until they are developed enough to strike out on their own. 


To me, this looks like a monster from Dune. Y’know, the kind to just burst out of the ground and start eating people. And to that gecko, it probably felt like it. The complete and utter lack of a face doesn’t help the look, though it does help the Marsupial Mole swim through the Australian sand where it calls home.
Image by Mike Gillam via ARKive

I love these things! It’s kind of cute, but also kind of sandworm

When they feed, the Cuttlefish shoot out two tentacles, which are usually tucked away in pouches under their eyes. This is done in a rapid whip-like action to seize their prey, then holding their prey within their arms while they consume it. (- nicolas.terry)


how do cats even work

A cat can jump up to five times its own height in a single bound.
The little tufts of hair in a cat’s ear that help keep out dirt direct sounds into the ear, and insulate the ears are called “ear furnishings.”
The ability of a cat to find its way home is called “psi-traveling.” Experts think cats either use the angle of the sunlight to find their way or that cats have magnetized cells in their brains that act as compasses.
One reason that kittens sleep so much is because a growth hormone is released only during sleep.
A cat has 230 bones in its body. A human has 206. A cat has no collarbone, so it can fit through any opening the size of its head.
A cat’s nose pad is ridged with a unique pattern, just like the fingerprint of a human.
If they have ample water, cats can tolerate temperatures up to 133 °F.
A cat’s heart beats nearly twice as fast as a human heart, at 110 to 140 beats a minute.
 Cats don’t have sweat glands over their bodies like humans do. Instead, they sweat only through their paws.
The claws on the cat’s back paws aren’t as sharp as the claws on the front paws because the claws in the back don’t retract and, consequently, become worn.
Cats make about 100 different sounds. Dogs make only about 10.
Researchers are unsure exactly how a cat purrs. Most veterinarians believe that a cat purrs by vibrating vocal folds deep in the throat. To do this, a muscle in the larynx opens and closes the air passage about 25 times per second.
A cat almost never meows at another cat, mostly just humans. Cats typically will spit, purr, and hiss at other cats.
A cat’s back is extremely flexible because it has up to 53 loosely fitting vertebrae. Humans only have 34.
Some cats have survived falls of over 65 feet (20 meters), due largely to their “righting reflex.” The eyes and balance organs in the inner ear tell it where it is in space so the cat can land on its feet. Even cats without a tail have this ability.
A cat can travel at a top speed of approximately 31 mph (49 km) over a short distance.
A cat’s hearing is better than a dog’s. And a cat can hear high-frequency sounds up to two octaves higher than a human.
A cat’s brain is biologically more similar to a human brain than it is to a dog’s. Both humans and cats have identical regions in their brains that are responsible for emotions.
And that’s how cats work.
Why does Komodo dragon venom act so slowly compared to other animals' venoms?


There is debate over whether komodo dragons have venom (ie a toxic substance secreted in glands within their body) or if they simply have a mouth full of bacteria, which works to their advantage when bringing down prey. From what I know it seems like the latter - as youngsters don’t have this ability, so it seems like over a komodo dragons life the bacteria builds up in their mouth. This would also explain why their “venom” acts so slowly.