chapter 26: mammals -...

Chapter 26: Mammals

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Phylogenetic Tree

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Kingdom: Animalia

Subphylum: Vertebrata

Phylum: Chordata

Class: Mammalia

19 orders

Over 5,000 species

3

Mammals

Most of today’s large land

animals

Most terrestrial

Some swim and fly

VERY efficient at retaining

water

4

Key Characteristics

1) Hair

2) Diverse and specialized

teeth

3) Endothermic metabolism

4) Mammary glands that

produce milk

Also have kidneys that

concentrate waste into small

volume of urine

5

1) Hair

Primarily dead cells filled

with keratin

Only mammals

Primary function =

insulation

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1) Hair

Color change = camouflage

Provide warning

EX: SKUNK ALERT! I

WILL STINK YOU RIGHT

OUTTA HERE!

Detect vibrations or protect

Ex: Quills and whiskers

Humans need clothes -

sparse hair and limited fat

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2) Teeth

Usually 2 sets

A) Baby teeth (Milk teeth)

B) Permanent Teeth

Uses: Secure & Chew food

Protection

Threat signal

Perform Tasks

8

2) Teeth

4 types:

1. Incisors

In front

Biting and cutting

2. Canines

Stabbing and holding

3. Premolars

crushing and grinding

4. Molars

Crushing and grinding

= faster digestion

9

2) Teeth

Highly specialized

Can determine diet by teeth

Which skull is from a

herbivore?

10

3) Body Temperature

› ENDOtherms - Generate

heat internally by rapid

metabolism of food

› active day or night

› Can live in very cold

climates

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3) Body Temperature

› Sustain activities that require lots of energy › Running, flying or

swimming

› Must eat 10x more food than ectotherm of similar size › Need efficient respiratory

and circulatory systems

12

Respiratory System Diaphram

Sheet of muscle that

separates chest and

abdominal cavities

Contracts = chest cavity

enlarges

○ Draws air in

Alveoli

Grape-shaped chambers

Increase surface area

More active = have smaller,

but more

Increase efficiency 13

Heart and Circulatory System

4 chambered heart

Septum completely divides

ventricle

Double loop

Oxygenated and

deoxygenated blood does not

mix!

14

4) Mammary Glands

On female’s chest or abdomen

Produce nutrient-rich milk High in protein, carbohydrates, and

fat

Water (prevents dehydration) and minerals

Ex: Calcium

Weaning - time when mother stops nurses young

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Parental Care

Young depend on mother

for long time Primates = longest

Male involvement varies

Some learn survival skills

with parents

16

Mammalian Diversity

Size Shrews- 1.5 grams

Blue Whales – 150 tons

Anatomy Bat

Forelimbs modified into wings

Body covered with hair

Whale Forelimbs flattened and paddle shaped

No hind limbs

Nearly hairless, streamlined body

Both use echolocation

Habitat Bat

Fly, active at night

Manatee Aquatic

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Reproduction

All use internal fertilization

One or more eggs fertilized

Variation in how/where zygote develops

3 groups (based upon developmental pattern) 1. Monotremes

2. Marsupials

3. Placental mammals

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1) Monotremes

Most primitive

1 order (Monotremata)

Australia and New Guinea

3 living species

Duck-billed Platypus

2 species of Echidnas (Spiny anteaters)

Lay eggs

Leathery shells

Female incubates eggs At hatching, newborns only partially

developed

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1) Monotremes

Only group of mammals to have a

Cloaca - common passageway

for digestive, reproductive, and

urinary systems

Adults do not have true teeth

Have hair and produce milk

No nipples

Milk oozes from glands on

mother’s belly

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1) Monotremes

Platypus

• Lakes and streams in Australia

• Broad, flat, webbed feet

• Eats crustaceans, worms, and

snails

Echidna

Terrestrial

Sharp, strong claws

Elongated, beak-like snout

○ Burrow and dig for insects and

invertebrates

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2) Order Marsupialia Kangaroos

Wombats

Wallaroos

Koalas

Opossums

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2) Marsupials

Young born days/weeks after fertilization

Tiny and undeveloped except for front limbs

Newborns crawl to pouch (marsupium) and attach to nipple ○ Grow and emerge, but return to

nurse

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2) Marsupials

Most in Australia

region

○ Result of Pangaea? Australia region broke

apart from Antarctica and

South America

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3) Placental

Mammals

Young develop in

uterus and nourished

from blood

Placenta

○ Organ

○ Allows diffusion of

nutrients and

oxygen from

mother’s blood

○ Waste materials

leave 25

3) Placental Mammals

Gestation period

○ Time between fertilization and

birth

Longer than marsupials

More completely developed at

birth

○ Some stand and walk within

hours

○ Others blind, deaf, and helpless

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Vary in size, shape, diet, and

habits

Variety of habitats

○ Hot to frigid

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3)Placental Mammals

Hooves

○ Specialize pad covering toes

○ Made of Keratin

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Horns ○ Core of bone surrounded by

sheath of keratin

○ Attached to skull

○ NEVER SHED!

○ Both sexes have

○ Note: Horns of a rhino are

composed of hair-like

keratin fibers NOT bone

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3) Placental Mammals Antlers

○ Males only

○ Made of bone

○ Covered by velvet (soft skin)

NOT covered by keratin sheath

○ When done growing, velvet dries

and falls off

○ Uses:

attract females

combat other males

○ Shed after breeding season

○ Grow larger each year indicating

age

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Domestic Animals

○ Kept and bred purposefully

○ Many selectively bred

More milk

Fine hair

Strength

Hybrids

- 2 different species

- EX: Mules

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Orders of Placental Mammals 19 including:

1. Order Rodentia

2. Order Chirotera

3. Order Insectivora

4. Order Carnivora

5. Order Pinnipedia

6. Order Primates

7. Order Artiodactyla

8. Order Perissodactyla

9. Order Cetacea

10. Order Lagomorpha

11. Order Sirenia

12. Order Probascidea

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Order Rodentia

40% of all mammals

Specialized gnawing

teeth

2 pairs of large, curved

incisors

○ Grow continuously

Intelligent

Small

Rapid Reproduction

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Order Rodentia

•1,500 living species

• All continents except

Antarctica

•Ex:

•Hamsters, guinea pigs

•Beavers, muskrats,

porcupines

•Woodchucks, chipmunks,

squirrels, prairie dogs, and

chinchillas

•We will discuss Rodents in

detail with our dissection lab!

34

Order Chiroptera Greek = “hand wing”

Ex: Bats

○ Capable of true flight

○ Front limbs modified into wings

○ Live in groups

○ Nocturnal

○ Most carnivorous

○ Use echolocation

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Side notes on Bats ~ 1000 species

Two groups

1. Megabats (Old World fruit bats)

○ Large

○ Africa, India, Australia, and Asia

2. Microbats

○ Small

○ Everywhere!

Smallest bat Kitti's hog-nosed bat (1 in) long

Largest Bat Malayan flying fox (16 in) and has

a wingspan of 5.6 feet.

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Side notes on Bats

Hibernation/Migration

Bats in WI survive by migrating or

hibernating in caves or mines.

Move to trees or buildings during

summer.

Some reside in caves year-round, using

different caves in summer than winter

Most return yearly to the same caves

Tree bats usually roost in trees during

summer and spend winter in hollow

trees.

Some make long migration flights

Brazilian (or Mexican) free-tailed bats

spend summer in SW U.S. caves and

migrate up to 800 miles to Mexico.

37

Misconceptions…

Not flying mice

Not blind Most see as well as us!

Fruit bats even see in color.

Do not try to become tangled in

hair. Bats have built in sonar hat

allows them to navigate at

break-neck speed through total

darkness.

Not ugly (well, you decide) or

dirty. They spend an enormous

amount of time grooming their

fur.

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Misconceptions… Not all are vampires. Only three are

and are mostly in Latin America.

Bats don’t ‘carry’ rabies. They are

capable of catching the disease just

like any other mammal.

Less than 0.5 % of bats contract

rabies. Grounded bats are more likely

to be sick. NEVER pick up bare-

handed.

Bats are among the slowest

reproducing animals. Most have only

one young per year.

Average life-span of a bat is 25 to 40

years

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Side notes: Bats in

Danger! White nose syndrome

A serious fungal disease

Affecting bats in NE US

Rings of white found around the nose

Most fungus is on the bats’ bodies and not

found internally

Threaten to add several types of bats to the

endangered species list.

Indiana bat is seen as at special risk

Many species of bats winter together in a

caves causing the spread

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White-Nose Syndrome

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Order Insectivora Eat mainly insects but also

fruit, small birds, and

snakes

Large appetite

○ Shrews eat 2X their

body weight daily

Very high metabolic rate

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Side notes: Insectivora… Long-pointed, flexible snouts

Well developed sense of touch

Poor sight and hearing

All have musk glands

Shrews: very short life and high

reproductive rate Female becomes pregnant within hours of

giving birth

The pygmy shrew is the smallest

mammal in North America

More than 70% of the Insectivora

are shrews

Other members include moles and

hedgehogs 43

Order Carnivora 2 groups

○ 1. Cat Family

○ 2. Dog Family

○ Strong

○ Intelligent

○ Keen sense of smell, vision, and

hearing

○ Long canine teeth

○ Most carnivorous

Raccoons, bears are omnivores

Pandas are herbivores

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“Dog” Family Gray Wolf

Coyote

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Wolves

Largest wild

members of dog family

Two species still living:

1. Gray wolves (Timber

wolves)

2. Red wolves

Known for pack structure

and complex social

behavior

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Wolves •3,000 to 5,000 wolves in early 1800s

•A state bounty was placed on wolves in Wisconsin

in 1865, and lasted until 1957.

•By 1900, wolves had disappeared from southern

Wisconsin. In 1950, less than 50 wolves remained in

extreme northern Wisconsin.

•In 1957 wolves were protected, but by1960 were

considered extinct.

•In 1967 and 1974 the U.S. Fish and Wildlife Service

designated the timber wolf a federally endangered

species.

•In 1975, wolves began to re-colonize Wisconsin in

the northwest portions of the state, along the

Minnesota border

•Wisconsin DNR completed a wolf recovery plan in

1989.

•2013 there were over 809 wolves

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Coyotes

• Smaller

•About 15 kg (33 lb)

•family groups consisting

of pair of adults and

offspring

•Usually hunt alone but

may hunt with one or two

others

•Now reproduce in

metropolitan areas

50

Jackals • 4 species in eastern

hemisphere

• Slender and smaller than

coyotes

• Big feet and fused leg

bones

• Capable of running 9.9 mph

for extended periods of time

• Crepuscular -most active at

dawn and dusk.

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Foxes

• Largest group – 21 species

•1.5 to 9 kg (3 to 20 lb).

• Pointed muzzles

• Long and bushy tails

• Large ears.

• Stalk prey and leap on it

with stiff-legged pounce

• Live in groups of up to 6

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“Dog” Family

Tracks meander, show claws

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“Cat” Family • Family Felidae

• Strictest carnivores of

mammals

• Most solitary

• Secretive

• Nocturnal

• Live in relatively

inaccessible habitats

• Around ¾ of cat species

live in forested terrain

• Agile climbers

• Native to every continent

except Australia and

Antarctica 54

Side Notes: WI Cats

•3 wild cats native to WI

•1. Cougar

•2. Bobcat

•3. Canada Lynx

• Only known breeding wild cat

in the state (Cougar)

•A fall population of about 3000

in northern Wisconsin, and

lower numbers in other

portions of the state 55

Side Notes: The Cougar

•Also known as:

•Puma

•Mountain Lion

•Panther

•American Lion

•Catamount

January 18, 2008 a cougar was sighted

near Milton, Wisconsin.

Was verified as 'cougar' from the tracks

and DNA from a small drop of blood from

a cut on the foot.

Wisconsin DNR is continuing to

investigate sightings and tracks in Rock

and Walworth Counties

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Side Notes: The Cougar

• Largest cat in US

• In the Americas, only the

jaguar is larger

• Ave: 75 to 160 pounds • Some males upto 265

pounds

• Males are 72 to 95

inches in total length

• Tail is 28 to 38 inches in

length

• Adults ~ 27 to 31 inches

at the shoulder

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Tracking

58

Tracking

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Side Notes: The Bobcat • ~ 20 pounds

• Large ears with pointed tufts of

hair at ends

• Orange-tan pelt with black

stripes on face and spots on

body

• Top of tail is black with white

underside

• Confused with the lynx

•Bobcat is slightly smaller

•Irregular dark markings only

on top half of tail

•Shorter tufts of hair on ears 60

Side Notes: Canadian Lynx • Ear tufts usually longer than 1

inch

• Tail is gray with black tip

• Longer back legs help in

springing to catch prey

• Large paws allow them to

walk on snow

• Favorite Food: Snowshoe

Hare

• Biologists estimate that for

every animal a lynx captures, it

misses ten.

• On average, a lynx kills every

other night, eating 150-200

hares a year.

61

Order Pinnipedia • Marine Carnivores

• Seals and sea lions

• Feed in ocean

• Rest, mate, and raise young

on land

• All 4 limbs modified into

flippers

• Streamlined bodies

• Insulating layer of blubber

• Most live in large colonies

(rookeries) headed by

single male

62

Side Notes: Pinnipedia… “true seals”

○ no ear flap

○ Largest: Elephant seal

2200 kg, weight of a minivan

○ Smallest: Ringed seal

50 kg, size of a small dog

Newborns have no blubber

Trap warmth and energy from

sun beneath fur

○ Shed fur

Have nictating membrane

Nostrils close underwater

63

Side Notes: Pinnipedia… Most live around Antarctica and

Arctic Circle

Antarctica has no permanent land mammals, but six species of seals

Whiskers help them navigate

○ Relate to direction and sound under water, with the help of the sensors in their skull

Feed on krill, herring, flounder, and salmon

Bulls breed several dozen females in a single season and have exclusive harems

64

Side Notes: Pinnipedia… • Walruses

2 species

1. Pacific Walrus

2. Atlantic Walrus

Prominent Tusks = elongated

canines

- Over a meter long

- Both males and females have

- Used to display dominance and

make and maintain holes in ice

Up to 4,500 pounds

Favorite food: clams on the ocean

floor

Hunted for meat, fat, bones, fur, and

tusks, which led to over-harvesting 65

Side Notes: Pinnipedia…

Walruses

Sparsely covered with fur

○ Blubber layer up to 15 cm (5.9 in)

thick

○ Air sac under throat

Acts as flotation bubble

Allows vertical bobbing in water

and sleep

Live ~ 50 years

Gestation period 15-16 months

66

Order Primates Humans, monkeys,

and apes

Most are tree dwellers

Flexible, grasping

hands and feet

Tail used for balance

Excellent depth

perception

Very curious

High learning ability

67

Primates

Nails instead of claws

Broad and flat

On at least one finger or toe

Sensitive pad

Stereoscopic vision enhanced sight

Reduced sense smell

Rely on vision more than olfaction (smell)

Increased brain size and complexity

68

Chimpanzee

Golden Snub Nosed Monkeys Spectacled Langur

Gibbon

Patas Monkey 69

Colobus Monkey

DeBrazzas Monkey Drill

Red Colobus Monkey

Douc Langur Monkey

Colobus Guereza

70

Mandrill

White Faced Saki Monkey Spider Monkey

Roloway Monkey

Emperor Tamarin

Squirrel Monkey

71

Order Artiodactyla Ungulates: Mammals with

hoofs

- weight supported by hoof

covered toes

Have EVEN # of toes

Most are herbivores and live in

herds

Young well developed

Move with herd shortly after

birth

Ex: Pigs, hippos, camels, deer,

antelope, cattle, goats, giraffes,

sheep

72

Order Artiodactyla Defenses:

○ Security of the herd

○ Run fast

Have a rumen:

stomach storage

chamber to break down

cellulose

Cud - partly digested

food that is regurgitated

73

More about Artiodactyla…

Pig, Red Deer, and Camel Feet 74

Order Perissodactyla Ungulates

ODD # of toes

Do NOT chew their cud

Have a cecum - pouch

branching from large intestine

○ Contains microbes that digest

cellulose

Fewer in number than

artiodactyls

Ex: horses, zebras, tapirs,

rhinos

75

Order Cetacea Two groups

○ 1. Predatory toothed whales, dolphins, and porpoises

○ 2. Filter-feeding Baleen Whales

○ Streamlined bodies

Modified front limbs = flippers

No hind limbs

Broad, flat tail

○ Blowhole on the top of head

○ Very intelligent

○ Communicates with clicks and whistles

76

More about Cetacea…

77

Order Lagomorpha Rabbits and hares One pair of continually growing

incisors

○ Additional pair behind front pair

Long hind legs for hopping

Rabbits ○ Build nests, female lines it with fur

○ Young born furless with eyes closed

Hares ○ No nests

○ Young born with fur and eyes open

78

Order Lagomorpha… Practice Coprophagy - Re-ingestion

of fecal droppings

○ First pass, food leaves partially digested

○ Fecal pellets, rich in protein and B vitamins, are re-ingested

○ After re-ingestion, pellets are drier and brownish when exiting

○ Allows animals to spend little time exposed to predators

Also practiced by beaver, voles, and by some shrews

79

Order Sirenia “Sea cows”

Dugongs and Manatees

Barrel-shaped marine animals

Front limbs modified into flippers

No hind limbs

Flattened tail for propulsion

Grazers

Found in oceans, estuaries, and

rivers

Closely related to elephants

80

Side Notes: Sirenia Lungs are unlobed

and flattened

Lungs and diaphragm

extend entire length

vertebral column

○ Helps control buoyancy

and maintain horizontal

position

The three manatee

species and the

dugong are all

endangered

81

Order Proboscidea o 2 living species

o 1) African Elephant

o 2) Indian Elephant

o Largest land animals

o Long, boneless trunk

o Are right or left-tusked

o Tusks differ in size, shape

and angle and can be used to

identify individuals

82

Side Notes: Proboscidea… Require huge amounts

of food 400 kg per day

Push down large trees to get food

Can be very destructive to crops and forests

Live 60-70 years

Complex social system

Excellent sense of smell

Poor sight and hearing

83

7 Remaining Orders

Summarized in table on handout (p.

816)

Let’s take a look . . .

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chapter 26: mammals -...

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