Marine mammals breathe air,
while most other marine
animals extract oxygen from the
water. Marine mammals have
hair. ... Marine mammals have a
thick layer of fat to insulate their
bodies and prevent heat loss. ...
Marine mammals are viviparous
Terrestrial
They have a synapsid skull (skull
with a hole behind the eye
sockets) with a head that remains
attached to the trunk through the
neck. They also have a backbone
as the central axis of the
body.They have a synapsid skull
(skull with a hole behind the eye
sockets) with a head that remains
attached to the trunk through the
neck. They also have a backbone
as the central axis of the body.