BRIEF REPORT Behavioral Development of a Polar Bear Cub (Ursus maritimus) in Captivity Katherine R. Greenwald 1n and Lisa Dabek 2 1 Brown University, Providence, Rhode Island 2 Roger Williams Park Zoo, Providence, Rhode Island The difficulty of observing polar bears (Ursus maritimus) in the wild has prohibited the gathering of behavioral data necessary to develop a baseline set of milestones for monitoring cub development. This study describes and quantifies previously undocumented trends in behavior observed in a captive cub– information that will be useful both in future comparative studies and in the implementation of husbandry improvements. Nearly 400 hr of behavioral data were collected, 100 hr of which were video recordings from the maternity den during the first 3 months of life. Den videos were scored to determine activity budgets and levels of maternal contact. For the remainder of the first year, mother and cub were observed in the outdoor enclosure. The onset and relative frequency of 40 discrete cub behaviors were tracked, as were patterns of mother–cub contact, including nursing and weaning. This study revealed that environmental conditions, habitat enrichment, and conditioning procedures influenced the patterns of developmental behavior exhibited by a polar bear cub. Both climatic and developmental factors had significant effects on the time the bears spent swimming. Management practices, such as environmental enrichment, and a conditioning procedure involving separation of mother and cub caused transient changes in several tracked behaviors. As the cub aged, the longest time between consecutive maternal contacts increased. Nursing bouts recorded per hour of observation decreased, and the duration of individual nursing bouts and pre- nurse begging periods increased. Zoo Biol 22:507–514, 2003.  c 2003 Wiley-Liss, Inc. Key words: infant development; activity budgets; enrichment; conditioning; weaning n Correspondence to: Katherine R. Greenwald, Department of Ecology and Evolutionary Biology, Box GW-208, Brown University, Providence, RI 02912. E-mail: kgreenwald@alumni.brown.edu Grant sponsor: Hughes Advanced Research Fellowship, Brown University. Received for publication August 19, 2002; Accepted November 29, 2002. DOI 10.1002/zoo.10095 Published online in Wiley InterScience (www.interscience.wiley.com). Zoo Biology 22:507–514 (2003)  c 2003 Wiley-Liss, Inc.