Meet the crabeater seal. This little guy comes from Antarctica and has the most specialized teeth in the carnivore world. Keep reading to know more about the crabeater seal.
Teeth to eat crab?
You might think that crabeater seals eat crab. Indeed, their Latin name is “Lobodon carcinophaga“, and carcinophaga literally means “crab-eating”. But here is the plot twist: crabeater seals do not eat crab. They feed on krill. How? By using their super-specialized teeth.
The teeth act as a sieve to filter seawater, just like the baleens in baleen whales. It allows the seals to feed on large amounts of krill all year long. In fact, scientists believe krill represents up to 90% of the crabeater seal’s diet. The rest of their diet includes cephalopods and some fish. This krill preference allows them constant access to a nutrient-rich food source not targeted by other seal species living around Antarctica. Therefore, the ecological success of the crabeater seal’s food choices probably explains why they can be found in huge numbers. The current estimates are of at least 7 million crabeater seals living in Antarctica. Scientists are currently working on getting better estimates, but some believe there could be over 50 million of them. This would make them the most abundant large mammal on earth!
Crabeater seals eat krill. Who eats crabeater seals?
It turns out the early life of a crabeater seal is no picnic. Indeed, a crabeater seal has an 80% chance to die during the first year of its life. This high chance of dying comes from the fact that crabeater seal pups are a popular snack for leopard seals. Even when the pups survive the first year, most of them show scars from leopard seals’ attacks. Other predators also include killer whales. Scientists believe that the high pressure on young crabeater seals pushed them to aggregate into large groups to lower the odds of getting eaten.
A long body to move on the ice
Crabeater seals have a long and thin body that helps them move on land. They use a snake-like motion to move on the snow/ice, leaving a serpentine trail behind them. They can actually be quite fast on land and reach 12-16 mph (19–26 km/h).
Interactions with humans
Since crabeater seals live exclusively around Antarctica, their contacts with humans are limited. Besides, crabeater seals are thought to be the most abundant seal on earth, so they are not threatened. They are designated as a least concern species on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species. However, with commercial fisheries exploiting Antarctica’s krill resources, there could be negative consequences for the crabeater seal. Also, if climate change negatively impacts the krill biomass in Antarctica, there could be a decrease in the crabeater seal populations.
Sources and further reading
- Kooyman, G. 1981. Crabeater Seal Lobodon carcinophagus. Pp. vol 2: 221-235 in S Ridgeway, R Harrison, eds. Handbook of Marine Mammals. London: Academic Press.
- International Union for Conservation of Nature (IUCN) Red List of Threatened Species
- Mori, M.; Butterworth, D. (2006). “A first step towards modeling the krill-predator dynamics of the Antarctic ecosystem”. CCAMLR Science. 13: 217–277.
- Erickson, A. W. and Hanson, M. B. (1990). Continental estimates and population trends of antarctic ice seals. In: K. R. Kerry and G. Hempel (eds), Antarctic Ecosystems. Ecological change and conservation, pp. 253-264. Springer-Verlag, Heidelberg, Germany
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