some run some walk some creep some sneak

But none swim?

Originally posted by Mookie:

is this how they were programmed? or is it a bug because that doesnt seem right at all

Definitely intentional, and they're both undead.

Skeletons and Draugr do not swim--they don't need to breathe. So they walk along the bottom underneath water. Been that way since the beginning. Oozes also move along beneath water, they don't swim.