Sea Lion Adoptions

There’s a lot of chatter about California sea lions in the news right now. Oregon’s coastline is seeing a number of beached sea lion carcasses suspected of leptospirosis infection.  The local news, as well as local blogs, are on an outreach mission to instruct the public not to touch or approach dead or dying animals and especially to avoid allowing pets near them or on the beaches with them.  I find it a little troubling that we have to remind the public not to interact with wild animals and even more troubling that one report noted a mother allowed her small child to pet one of the stricken sea lions as it died on the beach.

Um, in a word, ew.  In another: seriously?!

Leptospirosis is a bacterial infection, and is contagious across species.  For sea lions the infections typically produce heavy damage to the kidneys that is ultimately fatal for many (although it is treatable in rescue centers and among zoological populations).  One of the more curious symptoms of the infection is that it produces thirst sensations and drinking behaviors in sea lions. Why so curious?  Well, as with most marine mammals, healthy Zalophus usually meet their hydration needs from the liquids they consume in their juicy fish.

On the brighter side, researchers with Arizona State University recently published an article in PLoS One about the first known instances of adoption in this species.   I found it rather interesting, especially given my many hours spent observing a large and dynamic population of sea lions in an exhibit setting.  Females locate their pups in rookery settings (usually a single pup, although twins are possible) through a call and response bark and bleat.  Once the mothers have zeroed in on their target they verify their pups’ identity through a sniff test.  This little behavior usually draws the “oohs” and “aahs” from people because mother and pup will actually push their muzzles and noses right up against each other in something very like a kiss.  If females are adopting pups, they must be learning the new pups’ scent and vocal imprint.

I have to wonder though: why haven’t we seen such instances of fostering in the captive population of sea lions across all the zoos and aquariums maintaining them in the US?


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