Difference between revisions of "Crabeater seal"

Despite its name, the crabeater seal does not feed on crabs (the few crab species in its range are mostly found in very deep water). Rather, it is a specialist predator on [[Antarctic krill]] (''Euphausia superba''), which comprise over 90% of the diet. Their high abundance is a testament to the extreme success of Antarctic krill, the single species with the greatest biomass on the planet. There is little seasonality in their prey preference, but they may target adult and male krill. Other prey items include cephalopods and diverse Antarctic fish species. Although the crabeater seal is sympatric with the other Antarctic seal species (Weddell, Ross and leopard seals), the specialization on krill minimizes interspecific food competition. Among krill-feeding whales, only [[blue whales]] (''Balaenoptera musculus'') and [[minke whales]] (''B. acutorostrata'') extend their range as far south as the pack ice where the crabeater seals are most frequent.

Young crabeater seals experience significant predation by [[leopard seals]]. First-year mortality is exceedingly high, possibly reaching 80%, and up to 78% of crabeaters that survive through their first year have injuries and scars from leopard seal attacks. Long scars and sets of parallel scars, visible on the otherwise pale and relatively unmarked pelage of crabeaters, are present on nearly all young seals. The incidence of visible scars falls off significantly after the first year, suggesting leopard seals primarily target the young of the year. The high predation pressure has clear impacts on the demography and life history of crabeater seals, and has likely had an important role in shaping social behaviors, including aggregation of subadults.