Transcript Chapter 9 - mammals

Marine Reptiles, Birds, and
Mammals
Chapter 9
Marine Reptiles
• Skin covered with scales-prevents
water loss
• Eggs have leather shell to prevent
water loss as well
• Ectotherm-body temperature
fluctuates with environment
Sea Turtles
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Only 8 species of sea turtles
Armor-like shell called a carapace
Carapace fused to backbone
Cannot retract head into shell
Legs are modified flippers
• Leave water only to lay eggsreturn to same location every 2-4
years
• 100-160 eggs laid at a time
• Eggs hatch after about 60 days
incubation
• Eggs/young are easy prey
Sea Snakes
• Approximately 55 species of sea
snakes
• Ovoviviparous
• Carnivorous- fish/fish eggs
• Closely related to cobras
• Venomous bite
• Rarely aggressive
• Small mouth
• Hunted for skin
Other Marine Reptiles
• Marine Iguana-basks on
rocks to warm up after a
cold swim. Eats seaweed
and can dive up to 33 ft.
• Saltwater crocodile-lives along
the coast or in mangrove
swamps in the Indian Ocean,
Australia, and some Pacific
Islands. Among the most
aggressive of marine animalsmore feared than sharks.
Seabirds
• Endotherms- constant body
temperature
• Waterproof feathers (oil glands) to
conserve body heat
• Nest on land but feed mostly at
sea
• Webbed feet
• Some can fly
Penguins
• Flightless-wings are modified
flippers
• Spectacular swimmers
• Clumsy on land
• Adapted to cold temperatures- layer
of fat under skin; waterproof feathers
• All but one of 18 species live in
Antarctica
• Galapagos penguin- equator
• Larger penguins feed on
fish/squid
• Smaller feed mostly on krill
• Male protects the egg for 64 days
• Female feeds chick by
regurgitating her food until about
5 1/2 months
Tubenoses
• Tube-like nostrils
• Beak curved at tip
• Skillful fliers
• Catch fish at surface or
scavenge on dead
birds/whales
• Male/female faithful to each
other
• Incubation of young- 8 months
Pelicans
• Catch fish in pouch below beak
• Cormorants- black, long necks,
dive to pursue prey
• Frigate birds- narrow wings,
forked tails, catch prey from
surface or force other birds to
regurgitate fish in mid-air
Gulls
• Predators/scavengers
• Eat fish, eggs, young, from
garbage dumps, anything leftover
from humans
• Tern is a type of gull that hovers
over prey before swallowing it
whole.
Marine Mammals
• Endotherms
• Hair retains body heat
• Viviparous
• Has a placenta and mammary
glands
Seals, Sea Lion, & Walruses
• Pinnipeds
• Have paddle shaped flippers for
swimming
• Rest/Breed on land
• Predators (fish/squid)
• Layer of blubber under skin acts as
insulation, provides buoyancy, and
is a food reserve
• Males called bulls; females called
cows
• Main difference between a seal
and sea lion- seal cannot move
rear flippers forward
• Walrus has large tusks and feeds
on invertebrates, mainly clams
Sea Otters
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Smallest marine mammal
Lack a layer of blubber
Dark brown fur attracts hunters
Became almost extinct until
protected in 1911
• Playful and intelligent
• Spend most of time in water
other than breeding and giving
birth
• Live around kelp
• Eat clams, mussels, crabs,
sea urchins, and fish
Manatees (Sea Cows)
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Front flippers only
Gentle, peaceful
Live in groups
Strict vegetarians
Hunted for skin, meat, and oil
Reproduce slowly- 1 calf every 3
years
• All 4 species in danger of extinction
Whales, Dolphins, and Porpoises
are in a group called the Cetaceans
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Spend entire life in water
Breathe air- can drown
“warm blooded”
Produce milk for young
• Front flippers only
• Have a dorsal fin
• Blubber provides insulation
• Nostrils form a blowhole
• About 90 species, other than 5
species of freshwater species
Two categories of cetaceans:
1. toothless, filter-feeding
whales
2. toothed, carnivorous whales
Toothless, filter-feeding
• better known as baleen whales
• baleen is a flexible, fibrous plate
that hangs from upper jaw
• made of same material as hair
and nails
• feed by taking a mouthful of
water and squeezing it through
bristles- filter feed
• largest animals on earth
• two blowhole’s
• blue whale is the largest whale
of all- males average 80 ft and
females 110 ft
• other types of baleen whalesfin, humpback, right, bowhead,
gray
Toothed, carnivorous
• teeth adapted for fish, squid, and
other prey
• teeth only used to catch preyfood is swallowed whole
• one blowhole
• largest of this group is the sperm
whale
• material from squid beaks found
in stomach called ambergrisused in perfume
• killer whale is black/white and has
a taste for seals, penguins, sea
otters, and even other whales
• no confirmed cases of attacks on
humans
• Although small- dolphins and
porpoises are whales
Dolphins/Porpoises:
• Playful
• Social
• Easily trained
• Travel in “pods”
Whaling- whale hunting:
• In the 1600’s Europeans exploited
whales
• Harpooned from small open
boats- In 1800’s harpoons were
attached to explosives
• Blubber provided oil for soap and
lamps
• Killed for meat
• Whales have a very low
reproductive rate (about 2-3 years)
so this devastated the population
• Some nations even developed
ships that could process carcasses
at sea.
• Blue whales were a prime target.
One whale yielded 9000 gallons of
oil.
• 80% of the whales caught were
sexually immature. This added to
decreasing number.
• 1946-20 nations developed the
IWC (International Whaling
Commission) to regulate over
fishing
• IWC set annual quotas for the #
of whales to be killed
• Demand for whale products
decreased due to replacements,
so in 1972 the Marine Mammal
Protection Act of 1972 banned all
hunting of marine mammals.
• The affects of whaling are still
being felt.