Evidence of a maternal foraging cycle resembling that of otariid seals in a small phocid, the harbor seal

摘要: Lactation strategies in the two largest families of seals have been characterized as a phylogenetic dichotomy, with sea lions and fur (Otariidae) exhibiting foraging cycles true (Phocidae) strategy fasting. We show that lactating phocid, harbor seal, Phoca vitulina, has cycle similar to otariids. Time-depth recorders attached seal mothers revealed 9 11 females began bouts diving, averaging 12–40 m, by mid-lactation (12 days). During remainder lactation, made an average seven diving trips, lasting about 7 h. They returned rookery during interval between successive nurse their pups. Diving was more frequent daylight than at night increased duration lactation progressed. The behavior had weaned pups previously collected data from stomach lavage, suggest represent successful foraging. propose is intermediate otariids other phocids studied. like otariids, but typically resembles length rate mass gain pups, milk fat content. As are among smallest phocids, only slightly larger most it seems likely maternal size constrains amount stored energy can bring rookery, forcing them start feeding period.