Zookeepers making their rounds at Como Zoo made a surprising discovery Tuesday morning. They found that Lara the emperor tamarin had given birth to twins.

It’s rare for zoos to have the small species of monkey found mainly in South American forests and known for its most distinct physical feature: a long, white drooping mustache. But with the new arrivals, the St. Paul zoo now has six. There are only 28 on display at zoos across the country, Como Zoo officials said.

Visitors won’t be able to see the newborns for a few days. The tamarins are off-exhibit to allow them to gain strength and to bond with Lara and their father, Roger, zoo officials said.

By the time the new tamarins go on view with brothers Luke and Chewbacca, zoo officials may know their gender. It can take several weeks to determine that, the officials said.

The infant monkeys weigh about 40 grams, or about the size of a mini candy bar. Adult tamarins weigh about 1 pound when fully grown but can have a tail as long as 15 inches.

In another birth, the zoo welcomed its newest Dall sheep to the fold last Wednesday. The yet-to-be-named female is now on view and can be seen scampering around the exhibit she shares with her mother, Storm, and father, Thunder. She also has a one-year-old sister, Rainy.

Dall sheep are most notable for their curled horns.

The zoo’s newest giraffe now has a name. Violet was born July 21 and is the 21st giraffe born at Como over the past 24 years. The right to name the giraffe was an auction item during a recent fundraiser for the zoo and the Marjorie McNeely Conservatory. Violet stands 5 feet 11 inches, weighs 150 pounds and made her public debut last weekend.

At the same auction, a family won the right to name the zoo’s newest baby reindeer. The recent arrival was named Forest, a zoo spokesman said.