MAMMALS

• There are over 4000 species of mammals.

• A mammal is a warm-blooded vertebrate that has hair or fur and feeds milk to their young through mammary glands.▫The mammary gland is a structure in female mammals

that secretes milk.

• Live in Diverse conditions▫Land (Lion)▫Air (Bat)▫Water (Whale)

Characteristics

•4- chambered heart ▫Separated by valves that control the flow

•Lungs•Highly developed pair of Kidneys• Internal fertilization

▫With internal development▫Separate sexes

•Highly developed brain▫Considered the most intelligent animals▫Can learn behavior

Characteristics

•Body covered by hair•Movable eyelids•Secondary Palate (similar to crocodiles)

▫Separates air and food passages•Homeothermic (Warm Blooded)

▫Body remains at a constant temperature even though the surrounding environment may change

3 Ways of Classifying Mammals• Monotreme- egg-laying mammals• Marsupial- pouched mammals

▫Mammal is born underdeveloped and must complete development within the mother pouch

• Placental- have a placenta▫A mammal whose young are nourished

through a placenta as they develop more fully within the female.

▫A placenta is a structure through which food, oxygen, and wastes are exchanged between the developing mammal and the mother.

Teeth

•4 types of teeth are seen within all mammals1) Incisors are chisel shaped teeth used for

cutting.2) Canines are teeth used for tearing3) Premolars are teeth that grind food4) Molars are teeth that grind food

• The number and shape of the teeth depend on the type of food the mammal eats

MAMMALSEvolution

Classification

•Class Mammalia▫Subclass Prototheria (“first wild animal”)

Infraclass Ornithodelphia (egg-laying mammals) 1 order

▫Subclass Theria (“wild animal”) Infraclass Metatheria (marsupial mammals)

7 orders Infraclass Eutheria (placental mammals)

18 orders

Infraclass Ornithodelphia

•Egg-laying mammals•1 order (Monotremata)•Duck-billed platypus, anteaters, echidnas

Duckbill Platypus• Duckbilled platypus

lives in burrows near lakes or streams and uses its long snout to catch insects, worms, or crustaceans in the water.

• Has web feet for swimming.

• Lays eggs the size of marbles.

• Have mammary glands like all other mammals.

Infraclass Metatheria• Pouched mammals• 7 orders• Opossums, koalas, kangaroos, Wallabies

▫ The opossum is found in North America. ▫ The kangaroo and koala are found in Australia.

• Marsupial- a mammal who is born underdeveloped and must complete their development in the mother’s pouch.

• Marsupials develop only a short time in the mothers body (8 days after fertilization). At birth the tiny babies crawl into the mother's pouch to feed from the mammary glands.

Kangaroo Koala

Opossums

Opposum

•A young opossum spends about 2 months in its mother's pouch before it can be independent.

Infraclass Eutheria•Placental mammals•18 orders•Placenta mammals complete most of their

development within the mother's body and are more fully developed at birth than other mammals.▫Gestation period is the length of time the

young spends inside the mother. few weeks in mice 9 months for humans 18-23 months for elephants

•We are going to look 12 of the most common groups of mammals

1. Insectivores• Eat insects• Small, live in underground

burrows. • Examples: shrews, moles, and

hedgehogs.

• An Echidna is also an insectivore because it eats insects HOWEVER, we are talking about the placental mammals that eat insects.

2. Chiroptera or “Flying mammals”

• Bats are the only mammal that can fly

• Wings form from long arms and fingers that are joined by a thin, smooth skin.

• Flying squirrels don’t really fly they glide.

• Nocturnal - sleep during day and hunt at night

• Bats can't see well in the dark, so with their excellent hearing they give off high-pitched sounds that bounce off objects and sends back echoes to the bat. (Echolocation)

3. Endentates or “Toothless mammals”

• have few or no teeth.• Eat insects, worms, or

leaves.• Ex: anteaters,

armadillo, and tree sloths.

• The armadillo is the only mammal with tough bony plates covering its body.

Armadillo

4. Primates• Primates is a mammal that

has a well-developed brain and has an opposable thumb.

• An opposable thumb is one that can be placed against each of the other fingers. ▫ (This allows it to grasp

objects.)• Are the only mammals that

can make their own tools.• Are the most intelligent

mammals.• Examples: Humans, Apes,

monkeys, Gorillas, baboons

5. Rodentia or “Gnawing Mammals”

• have 4 sharp incisors (chisel-shaped teeth) for gnawing and cutting.

• The incisors continue to grow as long as the animal lives▫ This is helpful because the

teeth get worn down when they gnaw on hard materials such as wood.

• These are the most numerous types of mammals.

• Examples: Rats, mice, squirrels, beavers, hamsters.

6. Lagomorphs or “Rodent-like mammals”

• Have incisors like the gnawing mammals but have a small pair of grinding teeth unlike the gnawing mammals.

• Have well developed hind legs for running and jumping.

• Herbivores - eat plants.• Examples: Rabbits and hares,

pikas.

7. Cetacea or “Water dwelling mammals”

• Adapted to life in the water.• Have streamline bodies, and

hind limbs are fins or flippers.• Have blubber instead of fur• They must return to the

water's surface to breathe oxygen from the air. ▫ They have the nostrils or

blowhole on the top of their head.

• Examples: Whales, dolphins, porpoises.

• Intelligent and capable of communication with sound called echolocation system.

• Many show social behaviors.

8. Carnivora or “Flesh eating mammals”

• Have sharp canine teeth for tearing and shredding meat.

• Most specialized mammalian hunters.

• Keen sense of smell• Social/Family Behaviors

▫ teaching young, protecting and feeding each other

• Examples: Lions, wolves, bears, dogs, cats, raccoons, tigers, skunk.

Male lion

Female lioness

Skunk

Dog

Raccoon

Badger

Cat

9. Pinnipedia• Live in cold water habitats

but come onto land to copulate and bear young.

• Limbs less reduced than whales.

• Very clumsy on land.• Feed exclusively on fish

▫ Walrus feeds on mollusk• Examples: seals, walruses,

sea lions

10. Proboscidea or “Trunk-nosed mammals”

• long trunk, or nose.• Elephants are the only species

belonging to this order▫ There are 2 types of

elephants, African and Asian elephants.

• Largest land animals.• Males have tusks which are

very long incisors.• Must feed for as much as 18

hours a day.

11. Perissodactyla or “Odd toed Hoofed Mammals”

• Have hoofs in the place of toes and nails.

• Herbivores - plant eaters.• Example: rhinoceroses,

horses, zebra, giraffe

12. Artiodactyla or “Even Toed Hoofed mammal”

• Development of ruminant digestive system.

• some intelligence• development of horns,

antlers for defense• Ex: Deer, sheep, goats,

cattle, camels, pigs, hippopotamus