Marine MammalsBy: Lauren Howard & Lauren Ralston

Whales• They have blowholes that allow them to surface and breathe with

minimal effort• Whales are thought to have evolved from four-legged terrestrial

carnivores• Blubber provides insulation to conserve heat and reserve energy source

of water when fat is metabolized• Respiratory system, nervous system, circulatory system, and muscles

allow whales to dive great depths and remain submerged for over an hour• Bear usually one offspring at a time

Baleen Whales• Baleen is a structure used to strain the food from water• They feed by opening their mouth and swimming into dense groups

of fish• Baleen Whales include Right Whales, Bowhead Whales, Roquals, and

Gray Whales• Many Baleen whales are endangered due to impact of whaling• Mate and give birth in typically the same location and same time of

year

Toothed Whales• They use sound to locate objects, shapes, distance, and to

navigate•Whales pick up echoes (echolocation)• Includes Sperm Whales, dolphins, porpoises, Killer whales,

and Narwhals• The head of the porpoise is rounded, while dolphins are

identified by their beaks• Live in structured social groups called pods

Sea Otters• They float on their backs in the water• They are found mainly in kelp forests and on shallow coasts• They are a keystone species and they regulate the amount of

urchins in the ecosystem. Without them, the urchins would eat all the kelp, destroying the ecosystem.• Sea otter pups are nursed by the mother for the first year of their

lives and are taught how to swim and hunt for prey

Pinnipeds (Walrus)• They have large tusks that they use for pulling themselves out of the

water, self-defense, and protecting their mates. They are hunted for them because they are made of ivory and therefore very valuable• Walruses are carnivorous and their diet consists of crustaceans, sea

cucumbers, mollusks, worms, and other small soft-bodied animals• They are bottom feeders and this allows them to get their food easier

than mammals that have to hunt for it.• One male usually mates with about 23 females in a single mating

season

Sirenians (Manatee)• All manatees live in warm water. They live mainly in salt water but

always need fresh water to drink.• Their only teeth are molars and they become worn down due to all

the abrasive plants they eat.• One cow (female) will be approached by many bulls (males) and will

try to get away from them. The males will compete to be the first one to mate with the female. • They consume 4-9% of their body weight in food every day.