Swimming, Diving & Echolocation

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

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

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

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

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

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

Echolocation

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