In August, two baby Tree Shrews were born at The National Zoo. Keepers at the zoo had no idea until the pair were nearly fully grown! This is due to the secretive rearing habits of this small mammals native to Southeast Asia.

“One of the many things that’s interesting about [Tree Shrews] is the way they’re cared for as young,” says David Kessler, a biologist at the Zoo. “What happens is, as soon as they’re born, they’ll nurse, and they will drink up to 50 percent of their body weight in one nursing. Then they’re in a nest, and the female has her own nest separate from where they are, and she’ll only come and nurse the young once every 48 hours.”

Photo credits: Clyde Nishimura / SMithsonian National Zoo

As a result of this lack of contact, baby Tree Shrews remain nearly entirely hidden during the maturation process. Read more about Tree Shrews and this birth at the Smithsonian Magazine blog.