Marine Mammals

Comparative AnalysisBy Dr. M.

& Mr. K.

1.) Most are viviparous.

2.) Have mammary glands which produce milk to feed young.

3.) Young are usually altricial and need to be cared for by parents for a while.

4.) Are endothermic.

Traits

5.) Most are carnivorous (not marine manatee).

6.) Have well developed organ systems, especially the nervous system.

7.) Many are covered with fur, but some are not.

8.) Top feeders in Marine food chain.

Traits

PINNIPEDS

• Are fin footed mammals

• Are covered with fur

• Are excellent swimmers

• Are descendants of felines

Family’s of Pinnipeds

• True seals

• Sea Lions and Fur Seals

• Walruses

TRUE SEALS

• Have no external ears

• Hind flippers are permanently oriented backwards

• Wiggle on their bellies on land and swim via undulations of the body

TRUE SEAL

FLIPPERS

No external ear flaps

Fur coat

Seal molting clip

SEA LIONS AND FUR SEALS

• Have visible ears

• Hind flippers that can be rotated forward for use as limbs on land

• Walk or gallop on land and swim via powerful strokes of their front flippers

WALRUSES

• Have no external ears• Hind legs rotate forward• Only 1 species which lives in the artic

ocean• Eat shellfish and krill• Have tusks• Have air sacs in neck that can be inflated

PINNIPEDS ON PARADE

PINNIPED DIET

• Most Pinnipeds eat:

• Fish

• Squid

• Octopus

•Other invertebrates

PINNIPEDS ARE PREYED UPON BY

• Killer whales

• White sharks

• Other large sharks

• Lice

• Internal parasites

DIVING ADAPTATIONS IN PINNIPEDS

• Store oxygen in muscles• Have more blood than land animals in proportion

to their body size• Can direct blood flow to only vital organs• Can slow heartbeat to use less oxygen• Have a thick layer of blubber to protect them

from the cold• Have bigger lungs• Can slow metabolism

PINNIPED MATING

• Practice Harem Mating -a male defends a stretch of territory and mates with many females

• Females give birth within the males territory

• Some males are excluded and live in bachelor groups

PINNIPED MATING

• Giant Belligerent males mate with small females

• Males engage in pushing, biting , and bluffing contest

• Old males who lose disappear and are never seen again

PINNIPED LIFE CYCLES

• Females give birth to 1 pup then leaves the pup on land to feed at sea

• She returns once a week for a day long nursing session

• Pups enter the water 4 weeks after birth

• Males leave the island 1st, then females and pups leave in November for coasts south

HOW PINNIPEDS BENEFIT HUMANS

• Provide food

• Retrieve missiles for navy

• Retrieve traps and tools

• Entertainment

WHAT IS A WHALE?

TRAITS OF CETACEANS (WHALES)

• Mammary glands

• Endothermic

• Viviparous

• Smooth skin

• Blubber under skin

KINDS OF WHALES

• Odontecti - toothed whales

• Mysteceti - baleen whales

EVOLUTION OF WHALES

Characteristics of Odonteceti

• Conical shaped teeth• Smaller than mysteceti• Are carnivorous (eat fish, squid, etc.)• Can dive up to 2000 m• Can breath hold up to 90 minutes• Over 65 species• Sperm whale is largest toothed whale (65 feet)

Odonteceti continued

• Communicate while hunting• Live and travel in groups called pods• Some mate for life• Females and offspring travel in groups with last

year’s offspring• Some older males live in bachelor groups• Oldest males like Moby Dick live solitary lives• May migrate - wintering near equator and summering

near poles

Traits of Odonteceti

Teeth of odonteceti

WHALES HUNTING

DOLPHIN AND PORPOISE DIFFERENCES

• Dolphins• Have beaks• Conical teeth• 4m in length• Extroverted• Sociable • Live in groups

• Porpoises• No beaks• Spade shaped teeth• Reach 2m• Introverted or in pairs

Dolphin and Porpoise Differences

• Dolphin

• Porpoise

The family Dephinidae includes

Pilot whales

Belugas

Killer Whales

Bottlenose Dolphins

FLUKESFLUKES

• Each lobe of the tail is a fluke

• Flukes have no bones or muscles

• Muscles of back and caudal peduncle move flukes

• Spread of flukes=20% of body length

• Arteries and veins are oriented in a countercurrent system

COUNTERCURRENT SYSTEM

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

Adaptations for diving

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

• Water vapor is expelled through the blow hole

DOLPHIN SLEEP

• Russian studies show that dolphins may have deep sleep in one hemisphere at a time.

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• Express emotion

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• Worldwide calves are born all year• Usually give birth to 1 calf every 2 years• Calves are 42 - 48 inches and weigh 25 - 40 lb.• Calves may nurse for 12 - 18 months 2 - 3 hrs a

day 1 minute at a time• Dolphin milk is 17% fat, 10% protein, 71% water.

(human is 4.5% fat, 1.1% protein and 87.4% water)

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

• Echolocation video

Echolocation in a Sperm Whale

A. Blowhole

B. Frontal Air Sac

C. Distal Air Sac

D. Monkey’s Muzzle

ECHOLOCATION

• Gives the whale a detailed picture of the seascape

• Allows whales to dive to depths of 2,000 meters to locate prey and avoid injury in total darkness

ECHOLOCATION IN SPERM WHALES

• Clicks are generated by a pair of hard lips tightly compressed inside the skull called the monkey’s muzzle

• Sound is focused by an oil filled organ inside the head called the spermeceti organ (occupies 40% of whale length) once used in oil lamps and helps adjust density in the sperm whale

• Returning sounds are received by the lower jawbone and processed by the nervous system.

ECHOLOCATION IN SPERM WHALES

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

TRAITS OF MYSTECETI (BALLEEN WHALES)

• Have baleen instead of teeth• Are larger than toothed whales ex. Blue whale is

100 feet long and weighs 300,000 lbs. - Largest animal on earth

• Have 2 blowholes• Ribs are are not attached to sternum• Invent own stunts• Play competitive sports

HUMPBACK WHALES

• Eat enough in summer to last rest of the year

• Hunt together creating bubble nets to drive schools of fish close together and then swim up from underneath

• Communicate over long distances• Males sing long songs over and over

again to attract females• Breach, lobtail, and spyhop

HUMPBACK WHALES

BLUE WHALE

BALEEN

Baleen Whales Documentary