Meeting Abstract
Successful animals integrate morphology and behavior to produce diverse feeding strategies to consume prey in a variety of environmental contexts. Different strategies represent trade-offs between morphological specialization, prey choice, and energetic expenditure, and comparing strategies and their trade-offs is important for understanding individual and population level foraging success. Here we examined the underwater feeding strategies used by the endangered Hawaiian monk seal (Neomonachus schauinslandi), as poor foraging success seems to be driving the decline of some populations. Seven Hawaiian monk seals were fed five prey types of different sizes presented in three contexts (surface, midwater, benthos). Hawaiian monk seals used two strategies: suction feeding and biting, and these strategies involved specific behaviors and kinematics. Despite having a skull and dentition specialized for biting, Hawaiian monk seals used suction feeding most frequently (91% of all feeding trials), regardless of prey type and feeding context. However, biting was used most frequently when seals targeted larger prey (>70% of the seal’s head length), demonstrating that prey size influences the transition between strategies. In terms of trade-offs, suction feeding was 2.3 times faster than biting and involved a smaller gape and fewer jaw movements, allowing seals to quickly consume numerous small prey; biting was slower but resulted in 1.5 times more energy gained per time spent feeding. Maintaining both strategies results in increased behavioral flexibility, which is important as Hawaiian monk seals feed in an increasingly spatially and temporally dynamic marine environment.
