TRUE SEALS

Crabeater Seal (Lobodon carcinophaga)

The Crabeater Seal (Lobodon carcinophaga) is an Antarctic seal, present around the circumference of the continent, and sometimes further afield. Despite their common name, the seals do not routinely eat crabs, however, ‘Lobodon’ in the latin name, refers to their specialised “lobed” teeth which filter tiny crustaceans from seawater. L. carcinophaga are considered to be probably the most abundant pinniped species on Earth, and thus classified as Least Concern. Estimated population size = 8,000,000.
L. carcinophaga are medium large true seals (males up to 2.5 m long/ 402 kg, females up to 2.6 m/ 410 kg) with backwards-facing, long and slender hind flippers, and long, mildly pointed, fore flippers. Facially, the eyes are quite small and far apart, the nostrils large, and the mouths slightly upturned, with a dog-like muzzle. Their heads are rounded but not well defined from the body. Colouration of the coat varies with age, season, proximity to the moult, and individual, but generally  chocolatey brown to cream or silvery grey to whitish grey, with lighter undersides. Patches and spots can be present on the back and sides, behind the ear, and towards the tail.The bodies can often be heavily scarred on the face and front flippers from breeding season disputes, and on the body from predation attempts.
Feeding behaviour:
The major component of the diet of L. carcinophaga is Antarctic Krill (Euphausia superba), with the interlocking cusps on the aforementioned teeth creating a sieve that enables the seal to filter tiny krill from the water. Unlike many other phocids, L. carcinophaga is specialist in this feeding technique and is not a generalised feeder. Having said this, studies have shown they will adapt to include more fish and squid into their diet when krill is less available. L. carcinophaga feed mostly at night.
Breeding behaviour:
Sexual maturity – males 2.5-6 years old/ females 2.5-4.2 years old.
L. carcinophaga are seasonally monogamous. It is thought mating occurs in the water, and pups are born during the Antarctic spring from September to November, with a peak in October. After an 11 month gestation (including delayed implantation), the female will haul out on the ice to birth, and the male will then remain with the pair until the pup is weaned. The newborn pup has a woolly lanugo coat which is a light coffee brown colour, and is moulted after weaning. Lactation continues for an average of 17 days, at which time the male will separate the female from her pup in order to mate with her. Predation of the young by Leopard Seals (Hydrurga leptonyx) is extremely high at this time. The adults then moult their coats in January/February. Lifespan for individuals of the species that surpass their first year is generally around 20-25 years, though they can reach 40.
There are not any subspecies of L. carcinophaga, owing to the fact that the population is well connected.

Photos: Emma Weitzner (top) and Amanda Warlick

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