Why is the suction feeding mechanism paramount for walrus survival in the Arctic?

It bypasses energy-intensive shell crushing with molars

Energy conservation is crucial for large marine mammals maintaining body temperature in cold Arctic waters. The suction method is superior because it allows the walrus to rapidly process large volumes of relatively low-energy food (bivalves) without expending excessive energy. Crushing these shells using molars, which would be an alternative, would require significantly more muscular effort and result in much slower processing times. By using suction to extract only the soft tissue, the walrus maximizes its caloric intake efficiency relative to the energy spent during the feeding process, which is essential given the high basic maintenance energy needs of a large male walrus in cold water.