(what you took marine science to learn about) Marine mammals (what you took marine science to learn about)

Fact or fiction? FACT Fiction: 1 Hour FACT Fiction: 30 mph FACT 1. A blowhole is a modified nostril 2. A sperm whale can remain underwater for up to 3 hours 3. Dolphins can eat and swallow underwater without drowning 4. Killer whales can reach speeds of over 60 mph 5. A blue whale calf gains 200 lbs per day in its first year of life Fiction: 1 Hour FACT Fiction: 30 mph FACT

Classification: Kingdom: Animalia Phylum: Chordata Class: Mammalia Orders: Pinnipedia: Seal, Sea Lion, Walrus Carnivora: Otter, Polar Bear Sirenia: Manatee Cetacea: Whale, Dolphin

What Defines a Mammal? Endothermic (warm-blooded) Hair/Fur for warmth Internal development (nutrients via placenta) Nourishment via mammary glands Very large brain in relation to body size

Order: Pinnipedia Seals, Sea Lions, Walruses Evolved from early carnivores Paddle-shaped flippers Rest and breed on land Feed mostly on fish and squid Fusiform body shape Most live in cold water Very large to prevent heat loss

Harbor Seal: North Atlantic, North Pacific Elephant Seal: Mexico, Southern California Monk Seal: Tropical Locations Crabeater Seal: Antarctica Teeth!

Harp Seal California Sea Lion: trained barking circus seals Harp Seal Pup

The Importance of Blubber Thick layer of fat for warmth Food reserve Buoyancy in water

Sea Lions vs. Seals Seals Sea Lions Short Neck No External Ear Long Neck External Ear Posterior (back) flippers move forward for walking Anterior (front) flippers have no hair/nails and can rotate to support weight Short Neck No External Ear Posterior flippers cannot move forward Anterior flippers have hair/nails and cannot rotate backward

Sea Lions vs. Seals Sea Lions and Seals

Order: Carnivora Sea Otters and Polar Bears Closely related to dogs/cats

Sea Otter Characteristics Smallest marine mammals (60-80 lbs) No blubber, stays warm through air trapped in fur Must eat 25-30% of body weight per day Live in colder waters, usually in kelp forests How Do Sea Otters Stay Warm?

Sea Otter Eating Habits Usually eat urchins, mussels, and crabs Carry a flat rock in side pockets of loose fur and use it to crush shells of urchins and crabs

Polar Bears Found in polar north regions such as Canada Spend most time drifting on ice sheets Eat mostly seals

Order: Sirenia Manatees, Dugongs (aka sea cows) Relatives of the elephant Only front flippers, no rear limbs Vegetarians, eat sea grass Slow reproduction (one calf every 3 years) Only four species left (3 manatee and 1 dugong) Steller’s Sea Cow (now extinct) largest: 7.5 meters

Steller’s Sea Cow 1741: Explorers sailing through the Commander islands (near Alaska) discovered this living relative of the manatee Within 27 years of discovery, Europeans hunted it to complete extinction for its blubber (used to make oil), and its skin was used to make boats Easy target: very slow swimmer and not able to submerge Manatees and Dugongs

Manatees vs. Dugongs Manatees Dugongs Forked Tail Shorter and lighter Rounded tail Longer and heavier Rough Skin Forked Tail Shorter and lighter Smooth skin Nostrils flare outward

Sirenia Distribution

Order: Cetacea Whales, dolphins, porpoises Largest group of marine mammals Spend entire lives in water Very fish-like bodies (fusiform) Front flippers, no rear limbs 90 species- all marine except 5 freshwater dolphins Blowhole is a modified nostril Two sub-orders: mysticeti and odonticeti

Suborder: Mysticeti Baleen whales No teeth, feed through filter-feeding Blue Whale: largest species on Earth (27 meters) Why are Whales So Big?

How Does the Baleen Work? Baleen = flexible, fibrous plates made of keratin and hangs from upper jaws Whale intakes a mouthful of water, raises tongue and squeezes water out through bristles Food is then licked off the baleen

Gray Whale: North Pacific coastlines Right Whale: North Atlantic Types Right Whale: North Atlantic Bowhead Whale: Arctic

Rorqual Whales Accordion-like lower throat expands when feeding Examples: Humpback, Blue, Fin Whales

Order: Odonticeti Toothed whales: Beluga, Narwhal, Killer Whale (Free Willy), Sperm Whale (Moby Dick), Dolphins, Porpoises Teeth used to catch and hold prey, not to chew it Feed mostly on fish and squid

Bottlenose Dolphin (Flipper) Porpoise Sperm Whale Amazon River Dolphin Bottlenose Dolphin (Flipper)

Diving Adaptations Contain blood with increased concentration of RBC Muscle cells have more myoglobin than normal (myoglobin stores oxygen) Heart rate dramatically decreases underwater (elephant seal drops from 85 beats per minute to 12) Blood flow to non-essential body parts is decreased Lungs collapse to squeeze excess air out to prevent air from dissolving in the blood How a Seal Survives Underwater

Echolocation Sensory system based on hearing Nature’s version of sonar Used by all toothed whales and some baleen whales Low frequency sound waves are emitted by the cetacean Living Waters- Dolphin Echolocation

Nasal passages help to emit sound waves (clicks) The melon focuses these clicks into one outgoing beam Fat-filled lower jaw receives sound waves as they are bounced back toward the cetacean, and a sound picture is created by the brain

Cetacean Behaviors Large brain promotes learning and memory Humpback Whale Song Large brain promotes learning and memory Highly social animals, most live in large groups (pods) Communicate via many different types of sounds and vocalizations Humpback whale renowned for soulful songs used during mating Often assist injured members of their pod, many refuse to leave an injured or dying comrade Whalers knew a harpooned whale was a lure for others

Humpback Whale Breaching Dolphin Superpod Humpback Whale Breaching Scoliosis Caused by Beaching Why Do Whales Beach Themselves? Pod of beached whales in Australia

Reproduction (Pinnipeds) Internal fertilization on land Most seal species, males mate with only one female Elephant seals, fur seals, and sea lions: One male herds large harems of females (up to 50) All other males from “bachelor groups” Delayed implantation: Allows the birth of pups to be timed with the arrival of pregnant females in breeding areas (embryo remains dormant after fertilization

Reproduction (Cetaceans) Dolphin Giving Birth Internal fertilization, male reproductive organs also internal and extruded out of a genital slit when used Appear to have sex for pleasure as well as procreation Calves born tail first to prevent drowning Gray whales mate with the help of a second male to prop up female

Current Problems Whales and dolphins have been famously overfished for centuries Presently, dolphins are more threatened Less than 600 vaquitas left in the world Less than 100 Yangtze River dolphins Many get caught in tuna nets Suffering due to overfishing of tuna and squid (their food)

Conservation Efforts International Whaling Commision (IWC): est. in 1946, 20 whaling nations regulating hunting and overfishing of cetaceans Very hard to enforce Japan, Norway, Iceland still major offenders Marine Mammal Protection Act of 1972 (USA): Banned hunting of all marine mammals in US waters