Group of Marine Mammals

Md.Adnan

ASH1302032M

Session:2012-2013

Introduction

• Marine mammals are aquatic mammals that rely on the oceanand other marine ecosystems for their existence. They includeanimals such as seals, whales, manatees, sea otters . They donot represent a distinct taxon or systematic grouping, butrather have a polyphyletic relation due to convergentevolution. They are also unified by their reliance on the marineenvironment for feeding.

Characteristics

• Marine mammals breathe air – Although marine mammals live in and around the water they must come to the surface to breathe otherwise they’ll drown.

• Marine mammals are warm-blooded – In order to maintain their body heat marine mammals consume large quantities of calories and develop a thick layer of fat or blubber to keep their vital organs from freezing in cold environments.

• Marine mammals give birth to their offspring – Unlike fish and other aquatic animals whales do not lay eggs; instead they carry their children in their womb until they are born.

• Marine mammals produce milk – Marine mammals have mammary glands that produce milk which they use to feed their children. The milk is often full of fat and nutrients to help the child develop.

Major Groups

Marine mammals are mammals that are welladapted for life in the marine environment.Twomajor groups of marine mammals are:• Cetaceans:

– dolphins– porpoises– whales

• Pinnipeds:– seals– sea lions– walruses(under jurisdiction of the U.S. Fish and Wildlife

Service)

Dolphin

• Atlantic spotted dolphin

• Atlantic white-sided dolphin

• bottlenose dolphin

• Chinese river dolphin / baiji

• clymene dolphin

• long-beaked common dolphin

• Fraser's dolphin

• Hector's dolphin

• Indo-Pacific humpback dolphin

• Indus River dolphin

• Northern right whale dolphin

• Pacific white-sided dolphin

• pantropical spotted dolphin

• risso's dolphin

• rough-toothed dolphin

• short-beaked common dolphin

• spinner dolphin

• striped dolphin

• white-beaked dolphin

Indo-pacific Humback dolphin

Atlantic white-sided

bottlenose dolphin

Atlantic spotted dolphin

Characteristic of Dolphin

• PHYSICAL APPEARANCE :The dolphin can be identified by its round head and elongated snout. Its body tapers to its tail or fluke to create a streamline body shape.

• SOCIAL :Dolphins are extremely social animals that live together in groups of between two and 12. A group of dolphins is also referred to as a pod.

• PLAYFUL:Although the dolphin's playful side is what makes it a big attraction in captivity, Sea World reports that this behavior also has an important purpose for dolphins in the wild.

• INTELLIGENCE:The dolphin is known to be an intelligent mammal, and this can be observed by watching dolphins in captivity who are able to learn a wide variety of tricks.

• Diet :Dolphins consume a variety of prey including fish, squid and crustaceans.

Propoises

• Gulf of California harbor porpoise / vaquita

• dall's porpoise

• harbor porpoise

dall's porpoiseHarbor porpoise

Characteristics

• Diet:In terms of diet porpoises are known to consume fish, squid, and crustaceans as part of their primary food sources.

• Migration: When it comes to migration porpoise aren’t known to make long migration trips.

• SOCIAL STRUCTURE:Unlike some dolphin species, porpoises appear to be less social and tend to avoid interacting with humans or boats.

• Breeding: The average gestation period for a porpoise (the period between conception and birth) is about 10 – 11 months.

Whale

• Baird's beaked whale

• Blainville's beaked whale

• Cuvier's beaked whale

• Gervais' beaked whale

• Longman's beaked whale

• Sowerby's beaked whale

• Stejneger's beaked whale

• True's beaked whale

• beluga whale

• blue whale

• bowhead whale

• Bryde's whale

• dwarf sperm whale

• false killer whale

• fin whale

• gray whale

• humpback whale

• killer whale

Characteristics

• ECHOLOCATION AND NAVIGATION

• MIGRATION:Whales as a whole inhibit the entire worlds oceans and have an estimated annual growth rate of 5 – 15 percent.

• BREEDING:For whales the average gestation period can vary greatly ranging between 10 and 17 months depending on the species.

• Whales have two flippers on the front, and a tail fin.

• Whales are known to teach, learn, cooperate, scheme, and grieve

Humpback whale Killer whale

Bowhead whale Blue whale

Sea Lions

• California sea lion

• Steller sea lion

California Sea lion Steller Sea lion

Characteristics

• The physical features of a sea lion can vary from male to female.

• The California sea lion's body shape is a sleek and streamlined body;

• Their coat colors vary, adult males having a chocolate brown coat, while females and young males have a tan coat.

• A California sea lions flipprs are large and almost winglike.

Seals

• bearded seal• Caribbean monk seal• gray seal• Guadalupe fur seal• harbor seal• harp seal• Hawaiian monk seal• hooded seal• Mediterranean monk seal• Northern elephant seal• Northern fur seal• ringed seal• ribbon seal• saimaa seal• spotted seal

Harp seal

Spotted seal

Harbour seal

Gray Seal

Characteristics

• Body Shape:Harbor seals have a rounded, fusiform body.

• Coloration:Harbor seals range in color from light gray to silver with dark spots. Some are black or dark gray to brown with white rings.

• Foreflippers:Limbs are modified into flippers. The foreflippers, or pectoral flippers, have all the major skeletal elements of the forelimbs of land mammals, but they are foreshortened and modified.

• Head:A harbor seal has a rounded head with a fairly blunt

snout

• Tail:A harbor seal has a short, flattened tail tucked between its hind flippers.

• Refernces:

• http://www.whalefacts.org/

• http://www.whale-world.com/

• http://www.newworldencyclopedia.org/entry/Marine_mammal

• http://www.nmfs.noaa.gov/pr/species/mammals/