In Hooded seals, fasting periods coincide with periods of increased energy expenditure such as whelping, breeding and moulting. To prepare for this the seals undertake extensive foraging trips and feeding at depth (Anderen at al., 2014). Hooded seals then store the energy gathered from these foraging trips to be used in times of fasting in an expanding layer of blubber (Andersen at al., 2014). The males and females may avoid competition by foraging for similar food at different depths. The males seek out larger individuals of the same species that are found deeper in the water column, or they may feed on different prey entirely (Tucker et al., 2009). Hooded seals have been found to return to areas where they have previously had success in foraging. When they reach these areas they slow down and increase their turning rates to stay within the area, although they may not find an increase in prey encounters (Thums et al., 2011). It is likely that they feed primarily on Greenland halibut, red-fish, polar cod, blue whiting and squid (Blix, 2005; Tucker et al., 2009).
The diet of the Hooded seal changes between sexes and between adults and pups. Tucker et al (2009) found that the adult diet is dominated by Redfish, which only comprises a small amount of the diet in juveniles, however the juveniles consume more pelagic forage fish than adults. Both juveniles and adults consume the same amounts of amphipods and argentine. Tucker et al (2009) also found that there are sex-specific differences in the mean dive depths in the post breeding period of Hooded seals. These differences could indicate differences in sex specific costs of reproduction, body size or competitive ability (Beck et al., 2003). It is likely that the females eat higher energy diets than the males to meet the high energy costs associated with pregnancy, the males however may eat higher amounts of low foraging cost prey such as crustaceans (Tucker et al., 2009).