White rhino reproduction in managed care has been a difficult puzzle to solve, and it is still unclear why some female white rhinos fail to reproduce. SEZARC has been involved with trying to understand white rhino reproduction for many years, including conducting studies of behavior, endocrinology, and genetic diversity. Most recently, SEZARC has teamed-up with Omaha’s Henry Doorly Zoo and Aquarium and SeaWorld Busch Gardens Reproductive Research Center through a National Leadership Grant from the Institute of Museum and Library Services to develop tools that will promote successful reproduction even among females that have become acyclic or that do not have a male to breed with them naturally. This work includes the development of estrus synchronization and ovulation induction protocols, which cause follicles to develop on the ovary and ovulate so that they can be fertilized either naturally or by artificial insemination (AI). Our work with AI in rhinos has resulted in the birth of a greater one-horned rhino calf at Zoo Miami. This year, we are banking semen from carefully selected male white rhinos at White Oak Conservation. The semen samples will be sex-separated into x- and y-carrying chromosome sperm. Male rhinos must be housed separately in zoos, which requires a lot of space, so future AI attempts will use the sperm carrying the x chromosomes to ensure female calves are produced. Over the next few years, we plan to use this sex-sorted sperm to AI female white rhinos, and female calves will be born after the 16-month gestation.
SEZARC is also a collaborator in the American Institute of Rhinoceros Science (AIRS), along with the Center for Conservation and Research of Endangered Wildlife at the Cincinnati Zoo & Botanical Garden, The Wilds, Disney’s Animals, Science and Environment at Disney’s Animal Kingdom® Theme Park, George Mason University, and Stellenbosch University, South Africa, which has just received funding through another National Leadership Grant from the Institute of Museum and Library Services. AIRS will focus on addressing the primary scientific challenges facing rhino management in zoos. SEZARC will be engaged with identifying behavioral and environmental factors associated with wellbeing and providing management recommendations that will help our rhinos thrive. There are many possible indicators of wellbeing within five domains: nutrition/feeding, physical health, environment, behavior, and mental state. However, a systematic evaluation of ex situ rhino behavior, management, and physiology is needed in order to identify which indicators are the most meaningful for rhinoceros managers. Our research will characterize white and black rhino activity patterns, behavioral frequencies and durations, and temperament and the correspondence of those data with physiological indicators like hormone concentrations. A survey will be used to collect data on social and physical environments, husbandry methods, and rhino history. Once all these data and those of the other AIRS pillars (physical fitness, reproduction, and iron overload disorder) are collected, we will explore associations between them to understand rhino wellbeing in managed care.
