Territory quality of male sea otters in Prince William Sound, Alaska: relation to body and territory maintenance behaviors

摘要

Based on optimality models, lekking males holding higher quality territories should spend more effort on territory maintenance and less effort on body maintenance. We tested the hypothesis that benefits are correlated with costs for male sea otters, Enhydra lutris (L., 1758). Activity state was recorded during focal follows of 10 individuals (n = 127). Higher quality territories had larger area, more food resources attractive to females, a higher ratio of protective shoreline edge, and higher accessibility for females evading male harassment. Contrary to our prediction, territory quality was uncor-related with measures of cost: territory maintenance (patrolling, interacting) and body maintenance (feeding, grooming). We rejected the hypothesis that proximate benefits would be correlated with costs and suggested the following alternative working hypotheses: (i) given the high metabolic rate of sea otters, male breeding success may depend as much on maintaining body condition as maintaining a territory; (ii) higher quality territories with shoreline edge may not require additional patrolling effort; (iii) males may not expend extra effort in territory maintenance until more females come into estrus; or (iv) our seasonal measures of the benefits and costs of territoriality may not have accurately reflected factors influencing the switch between territorial and non-territorial tactics.