Dolphins and porpoises An interactive lesson By: Lindsey Redden

Some Pictures of Bottlenose Dolphins

Dolphin vs. porpoise DolphinPorpoise

Porpoises Family Phoecoenidae No distinct beak or rostrum Spade shaped teeth Smaller than most dolphins

Vaquita Smallest cetacean Only found in the Gulf of California One of the most endangered cetaceans. Only 600 left

Dolphin Family Delphinidae Larger Conical teeth Distinct beak or rostrum 37 species

Dolphin’s Head Well defined rostrum (snout) Conical interlocking teeth designed for grasping teeth Eyes are on the side of the head near the corners of the mouth Ears are located behind the eyes. Small openings with no external flap

DOLPHIN SENSES EXCELLENT VISION IN AND OUT OF WATER Eyes have rods (black and white) and cones (color vision) Skin is sensitive to touch Have taste buds No olfactory bulb, possibly no sense of smell

DOLPHIN SWIMMING Regularly swim at mph Burst of up to 40 mph Regularly dive feet Deepest trained dive up to 1,800 feet Average of breaths per minute Dives can last minutes

ADAPTATIONS FOR DIVING Heartbeat is reduced Blood is directed to vital organs (heart, lungs, and brain) Muscles have myoglobin, which stores oxygen and helps prevent oxygen deficiency

DOLPHIN RESPIRATION A dolphin exchanges % of the air in its lungs with each breath (humans exchange 17%) Dolphins inhale and exhale in less than 2 seconds

DOLPHIN SLEEP Dolphins are conscious breathers. They have to think to breathe. Dolphins sleep with one hemisphere of the brain at a time. They are never completely unconscious, so they can still breathe. In the first attempts at dolphin surgery, the dolphins died because they stopped breathing..

DOLPHIN BODY REGULATION Body Temperature is F Body Fat is about %

DOLPHIN SOCIAL ORGANIZATION

Social Behavior

FOOD Eat fish, squid, and crustaceans Eat 4 - 6% of body weight daily Do not chew their food but swallow it whole head first so spines won’t catch in their throat

REPRODUCTION Gestation is 12 months Usually give birth to 1 calf every 2 years Dolphin milk is 17% fat, (humans and cows are about 4.5%)

ECHOLOCATION IN DOLPHINS Air sacs - make clicks Melon - focuses clicks Lower jaw - detects returning sounds

ECHOLOCATION IN DOLPHINS page 2 Used to sense landscape in the dark Used to locate prey May be used to locate one another May be used to stun prey Works like sonar

Dolphin Intelligence Have a brain structure similar to humans Can process the complexities of social relationships when living in organized groups Have a large number of interconnections between neurons

INDICATIONS OF DOLPHIN INTELLIGENCE Can learn languages and respond correctly to sentences never uttered to them before ex. Frisbee fetch hoop Can rearrange environment to follow a command ex. Swim through a hoop, but hoop is on the bottom of the pool

Baiji (Chinese river dolphin, Yangtze river dolphin) Lived only in the Yangtze river Last seen in 2004 An intensive search in 2006 found no individuals. They were killed by illegal fishing, collisions with boats, and water pollution.

Amazon river dolphin Lives only in the Amazon river Color ranges from blue to grey to pink

Bottle nosed dolphin Found in most tropical and subtropical areas. Have many complicated behaviors and hunting techniques. Hunt cooperatively with humans in Brazil.

Various Dolphin species

Japanese Dolphin Hunt Every year Japanese fisherman kill thousands of dolphins in coastal bays. This is done from a belief that the dolphins compete with the fisherman for fish. The dolphins are usually sold for their meat, and some are used in marine parks.