What you need to know about slow lorises at Milwaukee County Zoo, adorable but venomous

Last November, the Milwaukee County Zoo acquired two pygmy slow lorises from the Brookfield Zoo in Illinois. The pair live in the nocturnal area of the small mammals building. It's the first time this species has lived in the Milwaukee zoo. Zookeepers hope to use the venomous primates to educate visitors about the dangers of illegal wildlife trafficking.

Rhonda Crenshaw, the zoo's small mammals areas supervisor, recently talked to the Journal Sentinel about the animals.

What are pygmy slow lorises?

Lorises are small nocturnal primates that live in trees in south and southeast Asian forests. There are 11 known species, one of which is the pygmy slow loris.

Slow lorises are endangered and can be found in Vietnam, Cambodia, Laos and southern China. They can be identified by the markings on their face which give them their nickname, Little Fireface, and by their large brown eyes, which help them see in the dark. Slow lorises on average measure less than a foot in length and typically weigh less than a pound.

Why are they endangered?

Slow lorises are on the list of the 25 most endangered primates. The reasons include habitat destruction due to deforestation for agriculture, as well as wild animal trafficking. Specifically, slow lorises are caught by poachers who sell them as pets, for tourist photo opportunities and to people who use them for traditional medicine.

What is wildlife trafficking? Why shouldn't slow lorises be pets?

Illegal wildlife trafficking usually involves the capture or poaching of endangered or protected species to sell for a variety of reasons, including to make products derived from the animals, and to use as pets or in tourism.

Illegal wildlife trafficking is dangerous for many reasons, including the decimation of animal and plant species and an increase in zoonotic diseases. An international treaty known as CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) maintains a list of species — currently at about 5,800 animal species — that are illegal to trade due to their protected status.

Not only is the pygmy slow loris on the CITES list, but it's also a bad idea to keep the animal as a pet for many reasons, including the animals' specialized diet and the difficulty in keeping more than one of the animals together in captivity due to their territoriality and venom.

How do poachers catch them?

Crenshaw said poachers take slow lorises from the wild because they're difficult to breed in captivity. One reason is their specialized diet — they're gum feeders, which means their preferred food is the gum found inside certain trees, which they extract with their teeth, something that isn't easy to replicate in captivity.

Crenshaw said slow lorises are relatively easy to catch in the wild. "Because they're nocturnal, poachers go in the forests at night and shine flashlights," said Crenshaw. "The slow lorises' eyes reflect the light, and they freeze when they're scared, which makes it easy to grab them."

After capturing them, Crenshaw said, poachers often pull the animals' teeth out with pliers — and without anesthesia — to prevent them from biting each other in the crates they're transported in.

They're adorable. How does that work against them?

Poachers sell slow lorises to wildlife traffickers because they're in high demand as exotic pets in some parts of the world and because they're popular in tourist areas where they're used for photo ops. People post the photos to social media, where they attract attention, making them even more popular to potential pet owners and tourists.

"People see their big eyes and some of the movements they're making and think they're cute and cuddly," said Crenshaw. "They do things like raise their arms and rub their bellies and get really still, but those are all things they do because they're scared to death."

How do they use their venom? Is their venom dangerous?

Slow lorises are the only known primate to be venomous. Crenshaw said the animals have an oily substance in a gland within their elbows, which becomes venomous when mixed with the lorises' saliva.

"They groom themselves with specialized front teeth known as tooth combs. Those tooth combs have grooves in them, so when they bite, the venom goes into the wound through the groove in the tooth," said Crenshaw. "They can use the venom for defense, but mostly they use it for competition between themselves because they're super territorial."

When slow lorises compete for territory, they will bite each other, and the venom will cause necrosis in the wounds, so they either take a long time to heal or can become deadly. Crenshaw said the venom will rarely kill a human, although it can result in a nasty wound.

The slow lorises also rub the venom on their backs or heads to protect themselves as well as on the backs of their babies to protect them from predators.

"If an animal tries to attack them, they can stand up with their front arms over their heads," said Crenshaw. "That makes them look bigger to predators and also gives them better access to their elbows to extract the oil. People think it's cute when they do that, but it's actually a defensive posture."

They're called 'slow.' Are they slow-moving animals?

Crenshaw said slow lorises "have a slow way of life" in that they often freeze or roll themselves in a ball with their hands over their heads when threatened and they stay very still in order to snatch insects out of the air. Slow lorises also go into a state of torpor (when their metabolism and body temperature drop in order to preserve energy), which can cause them to seem slow.

However, the animals can also be very fast, especially when they're moving through tree branches. Crenshaw said pygmy slow lorises have specialized blood vessels in their wrists to allow them to hold onto branches for a very long time without losing feeling in their hands.

"There's so much locomotion when they move through the branches," said Crenshaw. "They don't hop, but what they do is actually called a race walk as they go through trees."

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What should people know about the zoo's pygmy slow lorises?

The pygmy slow lorises who live at the zoo were both born in 2010. The male is named Henderson and the female is named Chantu. They came from the Brookfield Zoo near Chicago in November 2022. Crenshaw said the zoo will not breed Chantu and Henderson. Rather, they are kept together as a companion pair.

As Henderson and Chantu acclimate to their new environment, zoo staff keep tabs on them to make sure they're getting along. During the day (which the animals experience as night due to reverse lighting in the nocturnal portion of the small mammals building), the animals are kept together. Then, at night, Henderson and Chantu sleep in separate areas so they can get some alone time.

"We saw them grooming each other the other day," said Crenshaw. "Mutual grooming is a really good sign that they're getting along and that they can spend time together in close proximity without issues."

Crenshaw isn't overly concerned about the lorises' venom as zookeepers don't typically handle the animals. When they do need to touch them or hand-feed them, they use tongs or spoons and wear heavy gloves, something they do with all animals at the zoo anyway.

The zoo's pygmy slow lorises eat some insects and vegetables, as well as a type of gum that is similar to what they would get from trees in the wild.

Crenshaw said slow lorises in the wild make notches in the bark of trees, wait for them to ooze and then come back to eat the gum when it has hardened. She said they walk around all night, going from tree to tree.

"They should be chewing on bark, but we don't have gum trees at the zoo, so I'm working on mimicking in captivity what they would have to do in the wild," said Crenshaw.

Crenshaw is designing a device that will have gum inside tubes, with the tubes sunk inside wood. That will require the lorises to gnaw on the wood to get the gum out of the tubes.

Additionally, since pygmy slow lorises in the wild are constantly moving from tree to tree, Crenshaw and other zoo staff have placed several spots in their habitat, at different heights and different locations, to encourage Henderson and Chantu to move around their exhibit — leaves and sticks to chew on, mealworms and insects to catch, leaf bundles, nest boxes and "hidey spots" to sleep and rest in.

How is the zoo educating people about wildlife trafficking with the help of the pygmy slow lorises?

Chantu and Henderson's exhibit in the small mammals building currently has a sign in front of it to educate visitors about the animals, as well as their endangered status, the threats caused by illegal pet trade and suggestions on how to help, including avoiding social media posts that inadvertently encourage the lorises' illegal trafficking.

Crenshaw and her staff also talk to visitors about the risks to pygmy slow lorises when they see that they're interested in the animals. She hopes to expand those animal conservation education efforts with things like fundraisers and events.

"Eventually I hope to have a day when we can raise money for rescue groups," said Crenshaw. "At the zoo we have things like bake sales and fundraisers for different animals, and those are good ways to educate people."

What can people do to help pygmy slow lorises?

Crenshaw said a key thing people can do to help pygmy slow lorises is to make them less attractive to wildlife traffickers.

The Wildlife Trafficking Alliance encourages people to take a pledge to be responsible social media users by not "liking" or sharing posts, pictures or videos that depict people interacting with wild animals.

"Don't buy exotic animals, don't take pictures with wild animals as a photo prop and don't interact with the photos and videos online," said Crenshaw. She also recommended donating to rescue groups that are focused on slow lorises, such as The Little Fireface Project.