The National Zoo welcomed a pair of pygmy slow lorises on March 21, 2024 (Credit: Kara Ingraham/ NZCBI/ CC-BY-SA-2.0)

The Smithsonian’s National Zoo and Conservation Biology Institute (NZCBI) in Washington DC, is celebrating the birth of two adorable pygmy slow lorises. This is the first time the endangered primates have been born at the zoo. The twins are the first offspring of three-year-old Naga and two-year-old Pabu.

Naga and Pabu arrived at the NZCBI from different zoos in August 2022. After carefully examining their health and observing their personalities, the zoo's researchers declared the couple a perfect match, and introduced them in September 2023. As it turned out, they were right.

The zoo's Small Mammal House keepers found out about the birth the morning of March 21, 2024, when they spotted the infants clinging onto Naga. They believe the babies were born overnight. Since then, the keepers have observed the new mother lovingly carrying, grooming, and nursing her babies. Pabu has also proved to be a patient and attentive father. He is often seen looking after the twins when Naga goes in search of food.

The twins cuddle with their mother, Naga (Credit: Kara Ingraham/ NZCBI/ CC-BY-SA-2.0)

The keepers say the infants, who are weighed daily, are extremely healthy. They are also very alert and already curious about their surroundings. The twins will be named once their gender is determined in a few months.

“The babies make a very cool clicking vocalization and like to stick their heads out of the nest and check out everything around them,” says Ingraham, one of the Small Mammal House keepers.

As their name indicates, pygmy slow lorises are tiny. They measure between just 6 and 10 inches 15 to 25 cm) long.Though adorable, they are the only known primates to produce venom. The toxin is made in the glands of their upper arms. It is largely used to repel predators and warn other members of their species to avoid their territory. While not lethal to humans, the animal's toxic bite can cause intense pain. In some people it can even result in a severe allergic reaction.

The infants are the first pygmy slow lorises born at the zoo (Credit: Kara Ingraham/ NZCBI/ CC-BY-SA-2.0)

Pygmy slow lorises are endemic to the rainforests of South and Southeast Asia. The nocturnal animals spend most of their lives 10 to 40 feet (3 to 12 m) up in the forest canopy. The omnivores eat fruits and insects. But about 50 to 70 percent of their diet is tree sap. This makes them hard to care for in captivity.

Once found in abundance, their numbers have been significantly reduced due to the destruction of their natural habitats. The primate's adorable looks also make them a huge target for illegal pet trade. The NZCBI hopes the newborns will bring attention to the plight of these endangered animals.

"Every birth helps to keep a sustainable and healthy population of lorises under human care," says Ingraham. "When guests come to the Small Mammal House and see the lorises, they have the opportunity to learn about this unique and venomous primate and also to understand the threats they face in the wild and what they can do to help."