Chapter 26: Mammals 1
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Chapter 26: Mammals
1
Phylogenetic Tree
2
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
6
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
7
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
11
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
15
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
17
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
18
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
19
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
20
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
21
2) Order Marsupialia Kangaroos
Wombats
Wallaroos
Koalas
Opossums
22
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
23
2) Marsupials
Most in Australia
region
○ Result of Pangaea? Australia region broke
apart from Antarctica and
South America
24
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
26
3) Placental Mammals
Vary in size, shape, diet, and
habits
Variety of habitats
○ Hot to frigid
27
3)Placental Mammals
Hooves
○ Specialize pad covering toes
○ Made of Keratin
28
3) Placental Mammals
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
29
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
30
3) Placental Mammals
Domestic Animals
○ Kept and bred purposefully
○ Many selectively bred
More milk
Fine hair
Strength
Hybrids
- 2 different species
- EX: Mules
31
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
32
Order Rodentia
40% of all mammals
Specialized gnawing
teeth
2 pairs of large, curved
incisors
○ Grow continuously
Intelligent
Small
Rapid Reproduction
33
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
35
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.
36
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.
38
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
39
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
40
White-Nose Syndrome
41
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
42
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
44
“Dog” Family Gray Wolf
Coyote
45
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
46
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
47
48
49
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.
51
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
52
“Dog” Family
Tracks meander, show claws
53
“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
56
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
57
Tracking
58
Tracking
59
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 . . .
84
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