New Zealand's Auckland Zoo is celebrating the successful breeding and rearing of Lesser Short-tailed Bat twins. It's the first time this threatened endemic New Zealand species has ever been bred and hand-reared in a zoo. They are known as Pekapeka in Māori. 

The tiny Short-tailed Bats, a male and a female, were born in mid-November weighing a tiny 4 grams—less than a U.S. nickel!—and are now a healthy adult weight of around 14 grams.

New Zealand Centre for Conservation Medicine (NZCCM)Clinical Services Coordinator Mikaylie Wilson says, "While very rare to produce twins (one pup is usual), their mother had given birth to twins earlier but they did not survive. From this experience, we knew she wasn't able to cope with raising two, so the decision was made to pull the first twin at two days, and then the second at two weeks. The second pup was failing to thrive so we pulled it as well."

Photo credit: Ian Fish (1,2) / Auckland Zoo

See a video of the baby bats being cared for:

Wilson, who has experience hand-rearing bats in Australia, set up the program for the bats. She says, "We had a portable incubator that closely mimicked a nursery in the wild, keeping them warm and secure. The temperature of the incubator was at 28-29 degrees, and we were feeding them every four hours."

Mikaylie Wilson cared for the bats for five days straight, before training bird keeper Debs Searchfield started to play mom, feeding and caring for them at home.

Searchfield says, "We were a bit sleep deprived, but it was worth it. It's been such a great success to be part of, it's all very exciting and we've learnt a lot about them. Gaining more husbandry skills, hands-on techniques and knowledge will hopefully help the future of this species and other bats in recovery programs."

The bats' parents are descendants of a population from the Tararua Ranges in the lower North Island. They came from a group that were collected and translocated by the Department of Conservation to Kapiti Island in 2005/6. However, a fungal ear infection meant that this group was not suitable for release and the zoo now displays the only Lesser Short-tailed Bats in captivity.

New Zealand has just two native terrestrial mammals: the Long-tailed Bat and the Short-tailed Bat. Adults use echolocation to navigate and catch prey. Unlike most bats, which catch their prey in the air, the Short-tailed Bat has adapted to ground hunting, and spends lots of time on the forest floor, and folds its wings to use as "front limbs" for scrambling around. They eat insects, fruit, nectar and pollen. The Short-tailed bat is the only pollinator of the rare native plant, thedactylanthus or woodrose. They have a heart rate of 250 to 450 beats per minute while at rest, and 800 beats per minute while flying!