Lincoln Park Zoo scientists are assisting the recovery of endangered black rhinos in South Africa’s Addo Elephant National Park. Black rhinos were nearly driven extinct during the 1990s by habitat destruction and poaching, their population dropping from 65,000 to 2,000 animals.
With help from conservationists, the rhinos are slowly repopulating their historical range—recent surveys show 5,055 individuals—but because they are slow breeders, it’s important to understand the factors that naturally limit reproduction.
With more than 50 individuals, Addo currently boasts South Africa’s largest breeding population of the southwestern arid subspecies of black rhino. To form a clearer portrait of their health, zoo scientists use non-invasive field techniques—the collection of fecal samples—to monitor hormone concentrations and the presence of parasites. Sample collection is made possible by remote digital cameras that are employed to track rhino movement and habitat usage.
Hormone and parasite data will ultimately be combined with information on ecology, predation, competition and tourism. The resulting information will help scientists better manage and conserve this amazing endangered species.
Black Rhino Background
Rhinos in Peril
The black rhino is a shy, secretive species that is difficult to observe in the wild. (When we spot one, it’s very exciting!) Rhinos have a good reason for being elusive; they are poached for their horns, which, in some cultures, are used in traditional medicine and for ornamental dagger handles.
Rhino Pregnancy Test
The black rhino offers a charismatic reminder of prehistoric times, and it has also become an iconic species for conservation efforts. After a narrow escape from extinction, the black rhino is slowly repopulating its historical range.
However, continued reproductive success is critical for the species’ sustainability, especially given that it’s naturally a slow breeder. Understanding the factors that naturally control reproduction will help managers—in the wild and zoos—ensure that all black rhinos reach their reproductive potential.
Toward this end, we’ve developed a field kit that diagnoses pregnancy using black rhino fecal samples. We can use this information to determine the breeding success of rhinos in Addo Elephant National Park. Specifically, we can monitor the inter-calving interval (the timeframe between births) to determine how the environment impacts black rhino reproduction.
What can be learned from feces?
Hormones can be extracted from fecal samples, providing information on an individual’s reproductive state and stress levels. Also, the presence of parasites in the samples can be measured to provide an indicator of health and well-being.
How do the camera “traps” work?
Camera “traps” take photos when a laser attached to the camera senses motion nearby. The “traps” will be set up at rhino latrines (bushes where rhinos defecate to mark their territory) to help scientists match fecal samples with individual animals.
How are individual rhinos identified?
Each rhino in Addo Elephant National Park is immobilized at the age of dispersal from its mother (around 6 years of age), given a name and specific pattern of ear notches that can be used to identify it in photographs. Rhinos can also be identified by anatomical features such as their horn and scars on their bodies.
Rachel Santymire, Ph.D.
Director, Davee Center for Epidemiology and Endocrinology, Lincoln Park Zoo
Elizabeth Freeman, Ph.D.
Assistant Professor, George Mason University
Wildlife Field Technician
Rhino photos taken by Jed Bird.