Katrina Knott, Ph.D., Post-Doctoral Research Fellow, Conservation and Research Department, Memphis Zoo, Memphis, Tennessee
Andy Kouba, Ph.D., Director, Conservation and Research Department, Memphis Zoo, Memphis, Tennessee
Little is known about the reproductive physiology of polar bears. Relatively high mortality rates of cubs due to pregnancy loss and neonatal mortality is also of concern for both captive and wild populations. Urine is being collected from polar bears in North American zoos for non-invasive monitoring of reproductive hormones (i.e., metabolites of estrogens, progestagens, and testosterone) and an evaluation of potential pregnancy biomarkers (i.e., ceruloplasmin, prostaglandin, and cortisol). These data will be applicable to the conservation of both ex situ and in situ polar bear populations through characterization of reproductive events (i.e., optimal timing of breeding, implantation, pregnancy, and impending birth of cubs) as well as the concurrence of behavioral and physiological cues for successful breeding. Greater knowledge of the reproductive physiology of captive animals will also provide information regarding the timing and plasticity of reproductive events in free-ranging polar bears and insight into the potential causes of reproductive failures in declining populations.