February 26, 2020

It’s a Girl!

Denver Zoo Welcomes Its First-Ever Greater One-Horned Rhino Calf in a Boon for the Vulnerable Species

A rhino-sized effort led to a rhino-sized reward when our resident female greater one-horned rhino, Tensing, 13, welcomed her first calf on Saturday morning. Initial reports from our Animal Care team indicate that both Tensing and her calf are doing very well, and Tensing immediately started showing appropriate maternal behaviors, including nursing and grooming. The calf will remain behind the scenes in Toyota Elephant Passage for at least six to eight weeks to give her ample time to bond with Tensing under the watchful eye of their care team.

“The birth of this calf is the result of a truly heroic effort by our animal care, health and science teams and partners from other zoos to support the species,” said Brian Aucone, Senior Vice President for Animal Sciences. “It’s a significant event for several reasons, including the fact that this is the first greater one-horned rhino born at Denver Zoo, and because it was another very important step in reproductive science for animals in the wild and human care.”

The calf was starting to explore her new home in Toyota Elephant Passage hours after birth.
The calf was starting to explore her new home in Toyota Elephant Passage hours after birth.

Tensing’s pregnancy was confirmed in December 2018 after years-long effort that involved numerous experts from Denver Zoo and partner AZA-accredited zoos. Our Reproductive Specialist Dr. Anneke Moresco—with assistance from Dr. Monica Stoops from the Center for Conservation and Research of Endangered Wildlife (CREW) at Cincinnati Zoo (now lead reproduction scientist at Omaha’s Henry Doorly Zoo and Aquarium)—conducted 11 unsuccessful artificial insemination procedures with Tensing from 2014 to 2018. Drs. Moresco and Stoops attempted a 12th artificial insemination procedure with sperm from Jontu, a 10-year-old male from Omaha’s Henry Doorly Zoo and Aquarium in late 2018, and a voluntary ultrasound 10 days later suggested she was pregnant.

“Tensing’s journey from pregnancy to motherhood exemplifies the care our team provides to ensure our animals are able to voluntarily participate in their own medical care,” said Assistant Pachyderm Curator Lindsey Kirkman. “It took extraordinary patience and dedication over countless hours to make Tensing feel at ease with the artificial insemination and ultrasound procedures that ultimately resulted in a healthy mom and calf.”

Learn what it took to get Tensing pregnant and why this birth is important to the species

Once widespread, the population of greater one-horned rhinos—also known as Indian rhinos—plunged in the recent past as they were hunted for sport and had conflict with humans. Strict protection efforts have helped greater one-horned rhinos recover to an estimated 3,500 individuals worldwide, far more than the 200 that remained when the species was on the brink of extinction. The species is still listed as “Vulnerable” by the International Union for the Conservation of Nature due to numerous threats in their native range of northeastern India and southern Nepal, including human-wildlife conflict and poaching for their horns.

Denver Zoo works collaboratively with other AZA-accredited organizations to support the Greater One-Horned Rhino Species Survival Plan, a managed breeding program within zoos that ensures a healthy, genetically diverse population, and helps to safeguard the species’ survival. There are currently only 83 greater one-horned rhinos—including our newest addition—residing in North American facilities.

Get the latest updates on Tensing and her calf and find out when you’ll be able to visit Denver Zoo to see her by following us on Facebook, Twitter, Instagram and YouTube!


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