It's Loris Awareness Week! If you're already aware of lorises, it's probably because you've seen one of those viral videos of someone's pet. But if all you know is that they're cute, you're still unaware of what really makes lorises fascinating. The slow loris is one of the world's only venomous mammals, and those apparently adorable behaviors in the videos aren't quite what they seem.

Loris Basics

Ten species of loris are found in Southeast Asia, and their closest more-familiar relatives are the lemurs. "Lemurs and lorises are both categorized in the same group of primates called prosimians," says Chris Smith of the Duke Lemur Center. "Pro- means pre, simian means monkeys."

Lemurs and lorises evolved before other primates and share some unique characteristics. Their hands are less developed than those of monkeys and apes. "They can make fists, but they lack precision grip, so they couldn't pick up a piece of rice," says Smith. They also have what's called a tooth comb: six teeth on the bottom jaw that grow out instead of straight up.

And there's a connection between their lack of fine finger control and the existence of the tooth comb. "They can't use their hands to groom themselves like we think of chimps or gorillas sitting behind each other and picking insects off using their fingers," says Smith. "So they open the mouth and rake the toothcomb through each other's fur."

They've also essentially got two tongues. "Under the tongue toward the back of the mouth is a small piece of cartilage, not quite as flexible as the tongue," he says, which is used to clean out the toothcomb.

Lorises have an amazing grip, which they need because they can't jump, even over short distances. "I've seen them hold on to a vertical tree branch with their feet and extend their body completely perpendicular to the branch, only holding on with their feet," Smith says. "I don't know how many crunches in a day you'd need to do to do that."

Cute but Deadly

The slow loris is one of the very few venomous mammals. Its toxic bite is produced in an unusual way, by licking a gland on the arm that exudes an oil that mixes with their saliva.

Interestingly, the toxic protein that's formed by the combination is related to the one that causes people to be allergic to cats, and its effect is similar to a deadly allergic reaction. One case involved an Australian herpetologist, who, although well acquainted with similarly dangerous creatures, had no idea that the loris was venomous. So he thought it was kind of funny to have been bitten by this cute little mammal — till he started to swell up and his legs began to go numb.

"He took photos every fifteen minutes till he got to a hospital," says loris researcher Anna Nekaris. "By then his lips were thirty times their normal size and his tongue was so swollen he couldn't swallow."

Loris venom didn't originally evolve to affect humans, of course. "Mother lorises will put it on their hands and coat their infants with it," says Smith. "It seems to work as a predator deterrent." This is vital because unlike most primates, they leave their infants behind when they go out to forage.

But the venom is also used in much less nurturing ways — Nekaris says its main purpose may actually be to compete with other lorises, and the bites are gruesome and often fatal. "What the vets say in the rescue centers is that if a monkey bites another monkey, it looks terrible but it heals in a week," she says. "If a loris bites another loris, it's dead."

Don't Try This at Home

If, despite that, lorsises still sound cute, there are many reasons that keeping them as pets is still a terrible idea. The pet trade is devastating to the species as well as the individual animals. None are bred in captivity — even zoos have trouble breeding them — so they are all wild caught. And note that, as Smith says, "There's no such thing as a legal pet loris. The only way to get a loris out of the countries where they originate is illegally."

The smugglers have to do something about the fact that they're dealing with a venomous animal, so they'll pull out their teeth with pliers. "It's a roadside thing — there's no vet, no anesthesia, they're not wearing rubber gloves," says Smith. "We think a lot that are captured never make it — they die from that procedure."

Even the ones that make it will have shortened lives due to being kept in unnatural conditions. For one thing, they're nocturnal, and we humans are mostly not. "If you keep them up in the day, they're so stressed you reduce their lifespan enormously," Nekaris says.

And behavior that looks cute is often actually a clue that they're suffering. "If you see a loris on a bed or sleeping on a cushion, that's not natural to its anatomy and it gets very stressed," she says. "They reduce their body temperature and just become completely immobile and stare at you with little blinking eyes."

What's stressful to them in that situation is that in the wild, they're always holding onto branches with at least two and usually three limbs. "If I catch one to put a radio collar on, one of the first things I do is it give it a pencil — it calms it down immediately," Nekaris says. "The loris is freaking out until you give it something to hold on to."

You can see this in one popular video, she says: "The reason it's grabbing the umbrella over and over is that it's so desperate to hold on to something — and they keep taking it away."

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