I am aware that predatory marine mammals tend to have this sort of pointy dentition (see: dolphins) but since seals are superficially more land-animal-like it is still a surprise to see an odd dental formula like this. None of the usual 3/1/2-3/2-3 here, I just looked it up and leopard seals are 2/1/5 with the "5" being "postcanines". I'd not heard that term before.