The bottlenose dolphin (Tursiops) on
the right camouflages
with the water
(Office of Naval Research photo)
To blend into their environment, some marine mammals have countershading
(their top side is darker that their underneath surfaces). This
coloration, typical of many marine mammals, provides camouflage.
The result is that predators or prey do not see a contrast between
the animal and the environment because the top blends in with dark
depths when viewed from above and the light belly blends in with
the sunlit surface when seen from below. To the right is a picture
of an hourglass dolphin illustrating the general pattern of dark
upper dorsal coloration and light ventral (belly) coloration seen
in many marine animals.
Polar bears blend in with the snowy white
environment. These bears
will cover their
black nose and eyes with their paw to blend
(courtesy of NOAA)
Another example of camouflage is the coloring of the
polar bear. The polar bear is white to blend in with its snowy environment.
When sneaking up on prey, the polar bear will cover its black nose
with its paw to blend in perfectly with its surroundings.
Pinnipeds have large eyes for seeing in the low light conditions
often found underwater. In cetaceans, the eyes are located on the
sides of the head, but focus forward. Both the pinniped's and cetacean's
eyes are adapted to see well underwater. As a result, their in-air
vision suffers. Manatees have small eyes and fair to poor eyesight.
They seem to be farsighted and rely on touch to identify objects
A young bearded seal pup
(courtesy of NOAA)
Pinnipeds have small olfactory (sense
of smell) lobes, and evidence shows that smell is important when
interacting with other pinnipeds. Toothed whales do not have a sense
of smell, but baleen whales do have
some olfactory nerves. Cetaceans have
taste buds at the base of their tongue, and the common dolphin and
the bottlenose dolphin are able to distinguish (tell apart) certain
smells. Manatees have a good sense of smell and are often selective
in their food choices. Sirenians have many more taste buds than
their cetacean cousins, and this may contribute to their choices
of food. Polar bears have an acute sense of smell, and it is the
most important sense for detecting prey on land. A polar bear can
smell a seal more than 20 miles away!