Fig. 4. Total cost of foraging (bar height) in relation to prey type for adult sea otters. Each bar is subdivided into the energy expended for maintenance costs based on resting metabolic rate (black), locomotor costs calculated from the difference between single dive costs and resting costs (gray), and foraging/prey handling costs (white). The latter was calculated from the difference between total measured foraging metabolism and the two other costs, and includes the energy expended for locating, carrying and consuming the prey items as well as heat increment of feeding. Vertical lines above bars represent +1 s.d. The numbers in parentheses are the number of trials.