1. Swimming, Diving & Echolocation

2. Swimming Most representatives have streamlined bodies
Notable exceptions are the polar bear and sea otter
Pinnipeds swim using mainly their flippers
Some sea lions can swim up to 22 MPH
Cetaceans and sirenians swim using flukes in a vertical fashion
Swimming, Diving & Echolocation

3. Swimming To avoid inhaling water all marine mammals take quick breaths
Fin whales can empty and refill its lungs in less than 2 seconds
This is ½ the time we take
Cetaceans have the advantage of having a blowhole on top of the head
This allows them to breathe with most of the body remaining in the water
Swimming, Diving & Echolocation

4. Diving Physiology
Marine mammals have mastered the art of diving, this allows them to exploit food at considerable depths
Sea otters – 4 to 5 min. up to 180 ft.
Northern elephant seal – capable of depths of 5,000 ft.
Weddell seal – 1 hr & 13 min. and 1,900 ft.
Baleen whales do not dive deep and seldom dive deeper than 300 ft.
Toothed whales are excellent divers
Dolphins can dive 990 ft
Sperm whales can dive for over an hour at 7,400 ft
Swimming, Diving & Echolocation

5. Diving Physiology
Have more blood than non-diving mammals with a higher concentration of hemoglobin
Muscles are extra rich in myoglobin which allows for more oxygen to be stored
Swimming, Diving & Echolocation

6. The Dive Reflex Heart rate slows dramatically
Bradycardia
Blood flow to non-essential body parts is reduced allowing blood to be used where it is needed most
Vasoconstriction offsets dramatic drop in blood pressure
Water pressure collapses a flexible rib cage forcing air out of the lungs
Swimming, Diving & Echolocation

7. Echolocation
Marine mammals depend very little on smell, but do have good vision
Most have a sensory system based on hearing
All toothed whales, some pinnipeds and baleen whales
Echolocation is natures version of sonar
Swimming, Diving & Echolocation

8. Echolocation

9. Nice Melon! Melon - fatty structure found on the head
Focuses and directs sound waves
Sound is received by hollow oil/fat filled lower jaw
Sound passes to two very sensitive inner ears
Swimming, Diving & Echolocation