|
|
The Galápagos Sea Lion - A descendant of the California Sea Lion. Encounters with pups is the highlight of many snorkeling sessions. On land, they're equally entertaining and fascinating to watch. The beach master bull on the left has visible battle scars on his back and the "bump" on his head (covering
an area called a sagittal crest) is an indictaor of his breeding status.
an area called a sagittal crest) is an indictaor of his breeding status.
During the sea lion breeding season (mostly May-November), there are frequent battles on and off the beach. Most of it is posturing, with the weakest of the two in retreat, but sometimes there is a true
fight, with blood in the water, as seen above. The loser does recover, often after convalescing
in a "bachelor colony".
fight, with blood in the water, as seen above. The loser does recover, often after convalescing
in a "bachelor colony".
|
|
No matter the temperature, warm or cool, the sea lions like to touch, a behavior the scientists call thigmotaxis. They also have a heat exchange mechanism in their flippers, with the arteries and
veins being intertwined. The mechanism, technically called "arterio-venous anastomosis",
works similar to a vehicle's radiator. The sea lion on the right above is not stretching or
greeting; it's cooling off (or maybe warming up). Sea birds have a similar mechanism -
readily seen in cormorants and penguins.
veins being intertwined. The mechanism, technically called "arterio-venous anastomosis",
works similar to a vehicle's radiator. The sea lion on the right above is not stretching or
greeting; it's cooling off (or maybe warming up). Sea birds have a similar mechanism -
readily seen in cormorants and penguins.
For me, the most astounding behavior of pinnipeds (true seals and sea lions) is their deep diving ability/ physiology, with some species (e.g., the elephant seal) reaching depths over over 5,000 ft. without
getting the bends. There are many factors involved, including their ability to collapse their lungs
and significantly slow their heart rates. They also use the protein myoglobin to transport oxygen
to the muscles, where it is stored; this replaces the normal hemoglobin transfer of oxygen
to the body tissues.
getting the bends. There are many factors involved, including their ability to collapse their lungs
and significantly slow their heart rates. They also use the protein myoglobin to transport oxygen
to the muscles, where it is stored; this replaces the normal hemoglobin transfer of oxygen
to the body tissues.
But It's the sea lion pups that win the cuteness and "my favorite thing thing on the trip" awards.
BELOW - The Galápagos Fur Seal - which is really a sea lion. What's the difference? Several things, but to make it easy, if it walks, it's a sea lion; if it bounces like a blubber slug, it's a seal. There are no true seals
in the Galápagos, only sea lions. To look at a seal, check out the Antarctica section.
in the Galápagos, only sea lions. To look at a seal, check out the Antarctica section.
