CHICAGO (CBS) — Brookfield Zoo welcomed twin North American river otter pups recently, the first-ever births among the species in the west suburban zoo’s history.

The pups, a male and a female, were born Feb. 23 to mother Charlotte, who arrived at Brookfield in June 2012 from Omaha’s Henry Doorly Zoo in Nebraska, according to a statement from the zoo announcing the arrivals. Their father, Benny, joined the zoo family in August 2004 from Dickerson Park Zoo in Springfield, Missouri.

Brookfield Zoo recently welcomed a pair of North American river otter twins. (Credit: Jim Schulz/Chicago Zoological Society)

Otters typically mate between December and April, and most pups are born between February and April of the following year. They are born with their eyes closed, fully furred and weighing only about four ounces.

The pups remain behind the scenes, bonding with their mom and are learning how to swim, according to the zoo. They are expected to make their public debut later this month.

The otter pups are the first of their species to be born successfully at Brookfield Zoo. (Credit: Jim Schulz/Chicago Zoological Society)

The Chicago Zoological Society is a participant in the Association of Zoos and Aquariums’ North American River Otter Species Survival Plan.

Otter populations that were once in jeopardy in many places are recovering nicely, some from animals moving in from elsewhere and some from reintroduction programs over the last 20 years, according to the zoo.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2016. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)