Discerption of Aquatic mammals

1. AQUATIC MAMMALS

2. CHARACTER
Blubber – thick layer of fat to keep them warm
in the ocean
• Streamlined bodies – faster swimming
• Stores oxygen in muscles and blood - to stay
under water for long periods.
• More blood in proportion to their sizes
• Can slow their heartbeat – use less oxygen in
a dive

3. HABIT AND HABITAT
• - 20-30% are endangered/ threatened - Spend longer
time in water and breathe to the surface.
• SEAL- cold environment, among the most abundant.
• WHALES- migrate to warmer waters in the water
when food is harder to get in colder ecosystem.
• POLAR BEARS – feed on ice-associated seals,
spend most of their life on drift ice.

4. MODIFICATION OF ORIGINAL BODY
• Body shape – The body shape of aquatic mammal
become stream lined with elongated head and
indistinct neck and tapering posterior region.
• Body size and weight – Aquatic mammals develop a
layer body size which help to reduce heat loss and
due to buoyancy increased weight does not produce
any problem.
• Origin of flipper-Forelimbs are modified into skin
covered unjointed flipper .

5. • Upper valvular nostrils – The nose opening is move
to the dorsal side of the head that help animal to
breath air without exposing its body. Valve support
the nasal opening
• Mammary gland – In lactation the mammary duct
dilates and acts as storage of milk which is pumped
directly into the mouth of the young.
• Oblique diaphragm – It makes thoracic cavity larger
that provide more space for lungs.
• Large lungs – It allow the animal to stay for a longer
period of time under water.
• Endoskeleton– Modification of skull bone, cervical
vertebrae ribs can be seen bones are light, spongy
and fill with oil.

6. • Teeth– Various modification of teeth in
different orders can be observed, mobility of
jaws reduced.

7. LOSS OF STRUCTURE
• Lacrimal gland and all kind of skin gland are
absent.
• Skin is devoid of muscle and nerve.
• Pelvis portion become rudimentary.

8. DEVELOPMENT OF NEW STRUCTURE
• Foam – Thy have foam like substance made up of fat
mucus and gas in the middle ear which improve their
hearing under water.
• Melon – It is a receptor organ present in front of nostril
which detect pressure change in water.
• Harderian gland – This gland secrete a fatty substance
which protect the eye under water.
• Blubber – A thick subcutaneous layer of fat called
blubber act as a thermo regulator and maintain
internal body temperature. During deep diving it
absorb hydrostatic pressure.

9. • Baleen – In some whale the upper jaw develop rows
of numerous triangular horny plate called baleen,
serve as effective sieve to capture plankton.
• Tail fluke – Aquatic mammal develop large, lateral or
horizontal expansion of skin in their tail these called
tail fluke which are not supported by fin rays or
bones.
• Dorsal fin – They develop an adipose dorsal fin
which serve as rather or keel during swimming.

10. TYPES OF AQUATIC MAMMALS
• Amphibious mammals – These numerous live in
land but go to water for food and shelter. So they
show partial adaptation. e.g, Hippopotamus, walrus
etc.
• Completely aquatic mammals – These mammals
never come to land and are perfectly at home in
water. e.g, Blue whale,dolphin.

11. THE END