Predicting reproduction in captive sea otters (Enhydra lutris)

Publication Type:
 Journal Article
Year of Publication:
 2005
Authors:
 I. M. Da Silva, S. Larson
Publication/Journal:
 Zoo Biology
Publisher:
 A Wiley Company, Inc., Wiley Subscription Services
Keywords:
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ISBN:
 1098-2361
Abstract:

Abstract 10.1002/zoo.20020.abs The sea otter (Enhydra lutris) is a threatened species. It is also a popular exhibit animal in many zoos and aquariums worldwide. Unfortunately, sea otters reproduce successfully in only a small number of facilities. Pregnancies vary in duration, and are thought to involve a delayed implantation of about 2–3 months, followed by an implanted phase of 4–5 months. In this study we attempted to identify estrus and pregnancy states, and predict the date of birth in one female sea otter (Mali) housed at the Lisbon Oceanarium. We used different techniques to evaluate her reproductive status, including monitoring behavior to determine estrus, assessing weight changes to determine pregnancy and parturition date, and analyzing fecal hormone samples to determine estrus, pregnancy, and parturition date. During this study, Mali became pregnant four times. Her gestational length varied between 188–255 days. Weight increases >29 kg or 15% above baseline weight suggested pregnancy, and parturition was estimated to occur approximately 3 months thereafter. Fecal hormone (progestagens and estrogen) metabolite data gathered during two of her pregnancies showed that Mali’s delayed implantation phase of pregnancy lasted 43–109 days (a typical duration in other sea otters is 100–110 days). Mali’s implanted phase lasted a relatively long time (140–145 days compared to an average of 117 days in other sea otters). The combination of the three measurements was a powerful tool that enabled us to determine pregnancy and anticipate the arrival of a new sea otter pup. Zoo Biol 24:73–81, 2005. © 2005 Wiley-Liss, Inc.

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