The Sumatran rhinoceros is one of the most endangered animals on earth with just 300 individuals distributed throughout fragmented rainforests of South East Asia. A captive breeding program was formally established for this species in 1984, but efforts to propagate these rhinos in captivity failed. In 1997, CREW scientists initiated research using endocrinology and ultrasonography to learn about the reproductive physiology of the species. As a result, scientific breakthroughs led to the first Sumatran rhino calf bred and born in captivity in 112 years at the Cincinnati Zoo on Sept. 13, 2001.

On July 30, 2004, the Cincinnati Zoo repeated its success producing a second healthy Sumatran rhino calf. This achievement, proved that the first calf was not just a one-time-wonder and that the science of breeding this species truly has been developed at CREW.

An unprecedented third calf was born on April 29, 2007. This series of successful births clearly demonstrates how productive a captive breeding program can be when it incorporates good science, veterinary care, animal husbandry and intensive management. The Cincinnati Zoo remains the only place in the world breeding this species successfully in captivity.

In addition to its leadership role in the Sumatran rhino captive breeding program, the Cincinnati Zoo partners with the International Rhino Foundation to protect Sumatran rhinos in the wild by helping to support Rhino Protection Units (RPUs). These RPUs are trained by in-country Wildlife Departments to protect the rhinos from poachers, the greatest threat to the species. Furthermore, financial support and staff expertise are provided to facilitate the captive breeding programs at rhino reserves in Malaysia and Indonesia. The goal of the program is to keep the rhinos safe in the wild and to establish a successful international captive breeding program for the Sumatran rhinoceros.