A retrospective analysis of mortality in captive pygmy hippopotamus (Choeropsis liberiensis) from 1912 to 2014.

The pygmy hippopotamus (Choeropsis liberiensis) is an IUCN Red List Endangered species (CITES Appendix II) that has been housed in zoological collections since 1912. As wild populations continue to decline throughout the species' range, successful ex situ breeding and management, including an understanding of morbidity and mortality, are of utmost importance. This study is the first comprehensive review of mortality data from the captive population since 1982 and significantly expands on previous analyses. We solicited necropsy reports from 129/187 zoological institutions worldwide that currently or previously held pygmy hippos and received data for 404 animals (177 ♂, 220 ♀, 7 undermined sex), representing 43% of pygmy hippos that have died in captivity. Mortality in neonates was primarily due to perinatal causes (51.8%-stillbirth, failure to thrive, weakness, poor suckling reflex, maternal neglect) or parent-inflicted trauma (28%). Common causes of mortality in adult and geriatric animals included cardiovascular disease (16%), degenerative musculoskeletal conditions (10%), obstructive gastrointestinal disease (9%), and renal insufficiency (13%), sometimes associated with advanced polycystic kidney disease (PKD). Although not the direct cause of mortality, a number of adult and geriatric pygmy hippos were also overweight to obese. Infectious causes of mortality in included leptospirosis and encephalomyocarditis virus, the latter usually presenting as acute death due to cardiovascular demise. This comprehensive overview presents a useful guide for recommendations in preventative veterinary care and for improved husbandry and management of pygmy hippos in captivity. Zoo Biol. 35:556-569, 2016. © 2016 Wiley Periodicals, Inc.