Perth Zoo's first litter of baby otters in 18 years made their public debut this week during a checkup.
At 13 weeks old, the four male Asian small-clawed otters (Aonyx cinerea) are healthy and starting to become more active and adventurous, the zoo reports. Photos of the otter pups showed the zoo's veterinary staff handling them during their "physicals," during which the 13-week-olds received their second vaccinations.
"The pups, born on June 19, have just started to venture out of their nest box and explore their exhibit, including testing the waters of their pool," Western Australia's environment minister, Bill Marmion, said in a statement from the zoo.
The pups' parents, a female named Asia and a male named Tuan, both arrived at the Australian zoo last year as part of a breeding program.
"Asia and Tuan are doing a fantastic job raising the pups," Marmion said. "Typical for a male otter, Tuan has been observed nest building and taking food to the pups and is very watchful over his family."
Another breeding otter couple, female Boo and male Doan, also had a litter of four pups about a month later, on July 7, at the zoo. Those young otters, two males and two females, are currently in an off-display breeding facility and are slated to be transferred to Adelaide Zoo early next year, Perth Zoo said.
Asian small-clawed otters are the smallest of the world's 13 otter species, typically weighing just under 8 pounds (3.5 kilograms) when fully grown. They are native to freshwater streams, rivers, creeks and coastal regions in Indonesia, southern China, southern India, the Philippines and Southeast Asia. The species, which faces habitat loss in the wild, is listed as vulnerable on the IUCN Red List of Threatened Species.
Follow LiveScience on Twitter. We're also on &.