Friday mystery object #126 answer


On Friday I gave you a bit of a tricky mystery object in the shape of this partial skull:

I wasn’t expecting anyone to get it without some clues, but I underestimated my talented audience!

Jake spotted that it was a mammal based on the ear morphology and then worked out what kind of animal based on clues from henstridgesj who suggested seal and Julie Doyle, who managed to not only identify the species, but drop this lovely cryptic clue to convey that information:

Not a lot to phocus on, but……. I’m harboring an idea about who it might be.

It is indeed the cranium of a Harbour (or Common) Seal Phoca vitulina Linnaeus, 1758. It’s probably from a juvenile or fairly young adult, since the sutures aren’t very well fused and the muscle attachments aren’t as well defined as you might expect in a mature adult.

The squarish braincase is quite distinctive of seals, but the narrow frontal bones between very large orbits seems to have been the real give-away for identification this time. Those big eyes are well adapted for seeing in murky waters, with lots of light sensitive rod cells and a reflective tapetum lucidum layer that helps increase the amount of light captured (the same thing that makes a cat’s eyes glow in the dark).

 Harbor Seal, Point Lobos. Image taken by Clark Anderson/Aquaimages.

Harbor Seal, Point Lobos. Image taken by Clark Anderson / Aquaimages.

This species of seal is well distributed in the Northern Hemisphere and since they are inquisitive you may well have seen their heads bobbing in the sea and following you as you walk along a beach – they really are most endearing!

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