Mammals
Eukaryotes - Kingdom Animalia
General Characteristics
- Endotherms
- Hair instead of feathers
- Viviparous (live birth) with placenta
- Mammary glands
- Complex brain
Order: Pinnipedia
- Seals, sea lions, walruses
- Seals have rear flippers that cannot be moved forward
- Sea lions have external ears and rear flippers that can be used for walking
- Walruses have tusks used for defense
- Paddle shaped flippers for swimming
- Breed on land
- Predators, feed on fish and squid
- Thick layer of blubber keeps them warm, acts as a food reserve, provides buoyancy
Order: Carnivora
- Sea otters (Enhydra lutris)
- Smallest marine mammal
- No blubber, just fur
- Breed and give birth in the water
- Live in kelp beds and eat urchins, abalone, other invertebrates
- Polar bears (Ursus maritimus)
- Semiaquatic on Arctic ice
- Feed on seals
Order: Sirenia
- Manatees and dugongs
- Front pair of flippers, no rear limbs, paddle-like tail
- Feed on seagrass and other vegetation
Order: Cetacea
- Whales, dolphins, and porposes
- Breathe air, warm-blooded, produce milk
- Blubber provides insulation and buoyancy
- Blowhole is nostril on top of head
- Nutrition based on presence of teeth
- Toothless - baleen whales filter water for food (krill, herring, mackerel)
- Toothed - teeth used for capturing fish, squid, etc.
Types of baleen whales:
- Blue Whale
- Fin Whale
- Humpback Whale
- Minke Whale
- Gray Whale
- Right Whale - see below!
Types of toothed whales:
- Bottlenose Dolphin
- Pilot Whale - see below!
- Porpoise
- Killer Whale
- Sperm Whale
- Narwhal
- Beluga
Whaling
- Ambergris in perfume comes from indigested material in whale gut
- Blubber made soap and lamp oil
- Baleen for corset stays
- Trapped in tuna fishing nets
- Spermaceti for candles and lubricant
Swimming
- Flippers or tails, speeds from 20-40 mph
- Take very quick breaths to avoid inhaling water while swimming
- Spout (blow) of each whale is a little different
- Variations in direction and height
- Mixture of water vapor, mucus, seawater
- Blood vessels in tongue reduce heat loss through mouth during feeding
Diving
- Diving deep for long periods of time requires certain adaptations
- 90% lung capacity (vs. 20% in humans)
- Better oxygen storage - more hemoglobin and myoglobin
- Slowed heart rate during dive
- Blood flow to non-essential organs reduced
- Prevent nitrogen from being absorbed into blood by collapsing lungs (humans can't do this so we get the bends)
Echolocation
- Emit sound waves from melon in front of brain
- Analyze echoes reflected back through jaw bone to inner ear
- Low frequency clicks travel long distances, reflect from large features, provide info on surrounding topography, stun prey
- High frequency clicks provide more detail and locate nearby prey
Behavior
- Brain evolved to allow learning and responses based on past experiences
- Hihgly social, exhibit play behavior, care for injured
- Complex and very specific vocalizations used for communication
- Breaching (leaping out of water)
- Warning
- Scanning the surface
- Get rid of external parasites
- It's fun!
Migration
- Seasonal migrations from feeding grounds to breeding area
- Navigate using earth's magnetic field?
Reproduction
- Pairings
- Seals - one male with one female
- Sea lions- one male with harem of ~50 females!
- Whales do a little of everything...
- Giving birth
- Pinniped give birth on land
- Cetaceans give birth in water, tail-first
Random Pictures from our Gallery!
