This isn’t fossil evidence, but perhaps worth considering: One of the less common Pictish symbols (Dark Age Scotland) is sometimes called a “dog’s head” and sometimes called a “seal” — it has front flippers but a distinctly dog-like head with small, swept back ears. When I first saw it, my immediate thought was “sea lion,” but a quick check revealed the curiosity that you are all discussing: the conspicuous absence of sea lions from the North Atlantic. Could the sea lion have been hunted to extinction in those waters in the Middle Ages?

I guess I am still bitter about illegal whaling, the killing of mass numbers of dolphins (even though I dislike them), the overfishing that is done, and the light pollution from those fisheries.

I find it very curious that otariids would not branch out into Northern Atlantic waters simply because they are so widespread pretty much everywhere else and are quite adaptable. The sea lions of the Pacific for example have moved out and adapted to a wide variety of far flung habitats across the ocean where they have proven to be successful (when humans aren’t harvesting or killing them as the case with the Japanese sea lion). Otariids are fairly well established in some Southern Atlantic waters such as in South America and the Falkland Islands in the case of the South American sea lion Otaria flavescens, or Southern Africa in the case of the Cape fur seals and South African fur seals. It seems to me that there has been enough time for them to populate the North Atlantic regardless of the geographical limitations of the past. The Atlantic seems to offer enough resources and favorable habitats for it to have made sense for otariids to expand to take advantage of these resources. I am particularly interested in what the biological and ecological reasons for their conspicuous absence there might be. This is fascinating to speculate about.

Anyway, great discussion.

As for my notion explaining the conspicuous absence of the sea-lions from the North Atlantic, I’m compelled by the recent theories regarding a significant meteor impact 12.9KYA over northeaster North America and consequently the North Atlantic. It’s off topic a bit but the theory is nicely explained by the researchers at last years AGU meeting and recorded on youtube here:

Also, I read where the genetics of the current megafauna in N. America suggests that they re-populated the continent sometime in the not too distant past, which they’d naturally do, some from Eurasia (wolves, bears and caribou, etc), and some from Central America (mountain lions and bison, etc). Sea lions, not being creatures of the ice, like certain seals and walrus, would be blocked from an easy northern return, and the since the isthumus of panama has been in existence over the last 3 million years, they couldn’t use a tropical route.

Anyhow, it’s merely an exercise in speculation but I’ll keep my sensors tuned for news of otariid fossils from the North Atlantic in the mean time. cheers

To the best of my knowledge, there is no evidence of sea lion fossils in the Atlantic, as corrick said. I do think you have a good idea that fossils may be buried under the surface in areas that are beyond our current abilities to efficiently study. Also, I agree that sea lions could have feasibly branched out beyond the Pacific and into the Atlantic. They are indeed pretty adaptable and have settled into far flung habitats throughout the Pacific, such as Japan and the Galapagos Islands. I wouldn’t totally discount the possibility of them making their way into the Atlantic, but there is no evidence that I know of such a migration at the current time.

It would certainly be interesting to see what sort of fossils would turn up through such an avenue of research as you describe.