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 mammals
1) Incisors are chisel shaped teeth used for
cutting.
2) Canines are teeth used for tearing
3) Premolars are teeth that grind food
4) Molars are teeth that grind food
•
The number and shape of the teeth depend on
the type of food the mammal eats
MAMMALS
Evolution
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 (chiselshaped 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”
Male lion
• 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
Female
lioness
• Examples: Lions, wolves,
bears, dogs, cats, raccoons,
tigers, skunk.
Skunk
Badger
Dog
Cat
Raccoon
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