Zalophus wollebaeki
The smallest sea lion on Earth, and the only one that sleeps on a town bench at the equator.
Sea lions are cold water animals. Almost every species in this archive lives in cool or cold seas. The Galapagos Islands sit directly on the equator, and yet they hold a thriving sea lion found nowhere else, plus a separate endemic fur seal.
The reason is the ocean, not the air. The islands sit in the path of the cold, nutrient rich Humboldt Current sweeping up from the south, and of deep water upwelling from the west. That cold water carries the fish and squid a sea lion needs. Oceanographically, the archipelago is a piece of cold ocean parked on the equator.
Genetic work published in 2007 confirmed this is a full species rather than a subspecies of the California sea lion, and that the two lineages split about 2.3 million years ago. It is also the smallest sea lion in the world, adult females averaging just 156 cm, which is exactly what you would expect of an animal that has to shed heat rather than hoard it.
Galapagos sea lions can move over bare rock faster than a person can run. That single fact tells you which family they belong to. They are eared seals, and an eared seal's hip and ankle joints let the hind flippers swing forward underneath the body and take weight, so the animal stands on all four limbs, walks, climbs and gallops. On these islands that matters, because the haul out sites are jagged volcanic rock, tide pools, docks and the occasional moored boat, and getting between them means real overland travel. A true seal, whose hind flippers trail permanently behind, could not live here.
Their swimming is eared seal swimming too. The front flippers are long, wing shaped, hairless and black, and they row downward and backward to drive the animal forward, which is why the flippers look so oversized on such a small body. A true seal does the opposite, sweeping its rear half from side to side. Small tightly rolled ear flaps sit just behind the eye, pointed and easy to see because this species does not grow a mane to hide them.
The size gap between the sexes is real but gentler here than in most sea lions. Published measurements put males up to about 210 cm and females around 156 cm, and mature bulls carry a pronounced domed bump on the skull, a sagittal crest that steepens the forehead behind the eyes. Females and juveniles have no crest and look almost flat headed. Be careful with numbers you find elsewhere: some popular sources quote male weights of 250 to 400 kg, which is far above every published measurement. The largest male actually captured and weighed came in at 158 kg.
Every few years the eastern Pacific warms and the upwelling that feeds the Galapagos shuts down. This is El Nino, and for a Galapagos sea lion it is a famine.
The IUCN assessment puts the outcome bluntly. During strong El Nino events, 100 percent of pups, 50 percent of yearlings and substantial numbers of adults may die. Mothers cannot find enough food to make milk, and the youngest animals go first. Disease outbreaks of unknown cause have also broken out during these years, stacking on top of the starvation.
The 2015 event cut the archipelago wide count by nearly 24 percent in a single year, and pup numbers fell 40.5 percent between 2014 and 2016. They then rebounded 91.5 percent between 2015 and 2018, reaching 793 pups, the highest count of that survey series. That is the pattern: sharp collapse, partial rebound, no clear long term climb. Researchers who work on these islands argue that the thing to watch is not any one bad year but whether the bad years are arriving more often.
Most sea lions wean their pups somewhere around eight to twelve months. Galapagos sea lions frequently do not.
In a good year a female may wean at eleven or twelve months. But most keep suckling their yearlings into a second year, and maternal care has been recorded extending to three years. Some females nurse a yearling and a newborn at the same time. Because the breeding season is spread across nine months, from roughly May through February, there are dependent young on the rookeries all year round.
That long, flexible childhood is almost certainly insurance against a food supply that swings wildly. A mother who can stretch her investment across two or three years is buying protection against the year when there is nothing to eat. The cost is that she produces fewer pups in her life, which is one reason this population recovers so slowly from a crash.
Galapagos sea lions are famously untroubled by people. On San Cristobal Island one of the largest colonies in the archipelago sits on Los Marinos Beach in the middle of the town of Puerto Baquerizo Moreno, where the animals come ashore each evening and sleep on the sand, on benches, on docks and on moored boats. This is the same tameness Charles Darwin noticed when the Beagle reached the islands in 1835. Galapagos animals evolved with almost no land predators, so they never developed the reflex to run from an approaching mammal.
It is charming and it is dangerous, because it means they do not move out of the way of things that hurt them. Feral and uncontrolled domestic dogs kill pups and carry disease from the settlements into the colonies. A viral outbreak in 2001, possibly canine distemper, led to the death or euthanasia of 569 dogs. That same year the cargo ship Jessica ran aground and spilled fuel near Puerto Baquerizo Moreno. Plastic refuse entangles animals, and sharks take them, though juveniles and adults have been seen mobbing Galapagos sharks in shallow bays and driving them off.
How many are left is genuinely unsettled, and it is worth saying so. The population fell 60 to 65 percent between 1978 and 2001, from roughly 40,000 down to 14,000 to 16,000. The IUCN listed the species as Endangered in 2015 while stating, in its own words, that "the lack of quantitative survey information for the past 13 years greatly increases the uncertainty of this assessment." A later survey series published in 2021 estimated 21,493 animals in 2014 and 19,929 in 2018, with the change over that period statistically indistinguishable from zero. The honest summary is around 20,000 animals, badly hit by El Nino years, with no clear recovery and no clear further collapse.
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