Given the greater pressure underwater, i.e. at the bottom of the ocean, to survive there youd think that those animals would have stronger/denser bones, but we find that land animals have denser bones to withstand the higher net weight (gravity). But that seems counter intuitive because underwater the pressure is much higher at lower depths (like in the movies when submarines start to creak and get crushed under the pressure). So what's the deal? I know its a pressure vs force distinction but Im having trouble seeing it.