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Pinnipednesday - Arctocephalus galapagoensis Edition

Taking a quick break from discussions of Marvel and DC movie schedules, how about some pinnipeds?

The Galapagos Fur Seal (Arctocephalus galapagoensis) is the smallest species of eared seal, and can only be found in the Galapagos Islands off the coast of Ecuador, except for a small colony that dwells on Isla Foca off the coast of northern Peru. They prefer to haul out only on rocky shores, and actually spend a majority of their time on land. Rocky shores allow them to shelter under outcroppings to avoid direct and long exposure to the sun.

Adult male Galapagos Fur Seals are larger than females, growing up to almost 5 feet (1.5 meters) in total body length, and weighing about 141 pounds (64 kg). Females average about 4 feet (1.2 meters) in body length, and weigh only 62 pounds (28 kg). In contrast to most other pinniped species, Galapagos Fur Seals spend about 70% of their time on land, while most pinniped species divide their time on land and in the water 50/50. And the bulk of the time Galapagos Fur Seals spend in the water is used to hunt and feed.


While Galapagos Fur Seals are capable of diving to greater depths, they generall keep between 32 and 165 feet (10 to 50 meters) where they feed on squid and a variety of fish. They have rarely, however, been observed at depths of 554 feet (169 meters). During El Nino conditions, Galapagos Fur Seals must compete fiercely with each other for food, and will feed themselves before feeding their young. This means that if the adults do not have food to spare, the mortality rate among the pups and young seals is very high. When conditions are normal, however, there is usually plenty of food for the whole population.


Breeding season for Galapagos Fur Seals occurs from August to November, during which time the rocky shores are divided up among the females - each female expecting a pup will stake her claim to a birthing site. They only have one pup at a time, and it takes an unusually long time for pups to be weaned. It's not uncommon for females to give birth to a new pup with last year's pup still suckling, especially in El Nino conditions. Observations of mother-pup and sibling interactions have shown that the mothers tend to exhibit behaviors in favor of weaning the older sibling rather than neglecting the younger, which means that they will sometime act aggressively toward their older offspring if the younger pup is harassed into giving up its place at her teat.


The Galapagos Fur Seal does not have a lot of natural predators. While very rarely they are hunted by sharks or orcas, those two species don't pose a huge threat to its survival. They were heavily hunted in the 1800s, almost to the point of extinction, and their reproduction rate is extremely slow, and they are vulnerable to climate conditions. The Galapagos Islands are now considered a national park of Ecuador, however, so poaching is a rare occurrence.

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