PARENT SESSION
Monday, August 7, 8:00-11:30 am
COS 10 - Mammalian ecology
Sultana, Mezzanine Level, Cook Convention Center
Presiders: M Wolf

High complexity of whisker spot patterns of polar bears permits noninvasive individual identification.

Anderson, Carlos^*,1, Waterman, Jane¹, Roth, James¹, ¹ University of Central Florida, Orlando, FL

ABSTRACT- Studies of animals in the field often require identifying individuals within a population, especially in studies involving population dynamics, movement patterns, and social behavior. Capturing and handling animals for identification can be difficult and expensive, however, and may affect the health or behavior of the handled individuals. We evaluated the reliability of a noninvasive method of identifying individual polar bears based on whisker spot pattern variations. Digital photographs of the profiles of fifty polar bears, taken in western Hudson Bay, were chosen on the basis of image quality and angle with respect to the camera. Following a method of estimating the reliability of an identification system developed for lions, we divided spot patterns for each bear into characters that corresponded to cells on a regular grid. We calculated the probability of occurrence of a spot at each cell location and randomly generated 10,000 spot patterns based on these probabilities. We then estimated the overall complexity (i.e., information content) of each spot pattern. Over 99% of all spot patterns contained enough information to be distinguished from one another. These results suggest that an automated identification system based on the complexity of whisker spot patterns could be implemented to efficiently generate, store, and search a database of polar bears for identification in the field.

Key words: noninvasive identification, information theory, Ursus maritimus