Dolphins and porpoises An interactive lesson By: Lindsey Redden.
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Transcript of Dolphins and porpoises An interactive lesson By: Lindsey Redden.
Dolphins and porpoises
An interactive lesson By: Lindsey Redden
Some Pictures of Bottlenose Dolphins
Dolphin vs. porpoise
• Dolphin Porpoise
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
• 71-104 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 3 - 7 mph
• Burst of up to 40 mph
• Regularly dive 10 - 150 feet
• Deepest trained dive up to 1,800 feet
• Average of 1 - 6 breaths per minute
• Dives can last 8 - 10 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 80 - 90 % 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 98.4 0F
• Body Fat is about 18 - 20 %
DOLPHIN SOCIAL ORGANIZATION
• Live in groups called pods (2 - 20 in pods)
• Pods are based on age, sex, and familial relations
• Mature females and offspring
• Mature males and sub adult males
• Hunt together in teams
• Have dating rituals and friendships
Social Behavior
FOODFOOD
• 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.