Ultrasonography - the ultimate tool for Sumatran rhinos

Deep inside Way Kambas National Park, Indonesia, in a fenced sanctuary encompassing 100 hectares of natural rainforest, live five of the last Sumatran rhinoceros on earth. Just eleven of these primitive hairy rhinos are held in zoological institutions worldwide, making the Sumatran Rhino Sanctuary (SRS) holder of nearly half the extant captive population.

The goal of the SRS is to manage its captive rhinos to help augment wild populations that remain threatened. The animals are part of a global managed breeding programme for the species, with hopes of adding numbers through reproduction and new scientific knowledge that will enhance our understanding of these rare and secretive forest rhinos. Andalas, a new herd bull, arrived at the Sanctuary in early 2007 and brought with him a revival of hope for the sanctuary breeding programme as the centre’s newest breeder. He is now meeting the females on a daily basis and has already been introduced to his future mates.

Sumatran Rhino and staff at the sanctuarySumatran Rhino Sanctuary staff feeding the rhinos - Credit Sumatran Rhino Sanctuary

Making the decision on when to put the rhinos together at the right time can be a challenge, especially for a species like the Sumatran rhino that is largely solitary in the wild and would not normally associate with another adult until the female is near oestrous and receptive. Drs. Dedi Candra and Andriansyah work together with the rhino keepers to ultrasound each female on a regular basis to learn about each female’s reproductive cycle.

Ultrasound is now a practical piece of the rhino veterinarian’s medical equipment arsenal and allows one to plan the male and female rhino mixings based on the size of the female’s follicle (which contains the maturing egg). Work done at the Cincinnati Zoo has helped guide efforts to introduce rhinos at the most opportune time. Of course, if a female does become pregnant, the ultrasound will also help make the exciting diagnosis by allowing the doctors to directly visualize the foetus. Part of the effort is based on sound science – the ultrasound allows one to carefully measure and record the daily changes in each rhino female’s developing follicle. And another part is based on sound management – following behavioural clues to help guide the most opportune moment to open the gate that separates the male and female rhinoceros.

A great deal of hope rests on Andalas as a future breeding animal for the Way Kambas Rhino Sanctuary, and with the help of ultrasound we may one day soon see the beating heart of an unborn rhino.

(A version of this article was originally published in The Horn, Autumn 2009. Author: Drs Robin W. Radcliffe, Dedi Candra and Andriansyah, Sumatran Rhino Sanctuary)