Sea Lion

How can I tell a sea lion from a female walrus and where do dolphins have hair?

I recently went to the aquarium, it was fun but I was hoping to see some walruses (walri?). Then my mom and I saw this sign which said “our female walruses are being tested for pregnancy, once one test comes back positive we will bring some males in!” My mom said female walruses do not have tusks like the male does…so does that mean one of the sea lions or seals we saw was actually a female walrus?
And if a dolphin is a mammal, and all mammals have hair, then where do dolphins have hair? I know whales have those bristly things where the teeth should be in any other mammal, but dolphins obviously have teeth, and where a whale has a fine coating of tiny hairs all over, a dolphin seems to have none at all.
Thanks in advance!
Yeah I didn’t think the sea lions were actually walruses but…then where are they?
My guess qould be that since they are trying to get them pregnant they have them put away…
But how do you get them pregnant WITHOUT the males?

Second question first:
Actually, the whale’s hair isn’t the baleen. Some whales have mustaches, and almost all have very short hairs that end at the outer layer of skin. Those bumps on humpback whales? Those are its hair follicles.
Dolphins do have hair, but again, the hair ends at the skin. The follicle doesn’t hold the root very tightly, so water moving across the skin yanks out the hair. Some dolphins are born with hair resembling a mustache or beard.

First question:
No, the sea lions you saw were not actually female walruses. Walruses are HUGE, ugly, and have mustaches (females and males both). And they do have tusks.

http://www.allposters.com/-sp/A-Female-Walrus-Nuzzles-Her-Infant-Posters_i1009263_.htm

As for sea lions: They’re smaller, and much thinner, and have more streamlined bodies.

http://www.psych.ualberta.ca/~varn/Galapagos/sea_lions.html

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