MAMMALS
I.
Characteristics
A.Body covered with hair
1. As with the feathers of birds, and the “shed”
of reptiles, mammal’s fur is made from the
protein keratin.
2. There can be up to 3 types of hair: guard
hairs, under fur, + vibrissae.
B. Skin glands are numerous. They include: oil
glands, sweat glands, lacrimal glands, scent
glands, + mammary glands.
MAMMALS- SKELETAL FEATURES
1. Usually a relatively large brain
case (cranium).
2. Generally 7 cervical vertebrae
SKELETAL FEATURES- DENTAL FORMULA
Incisors-Function=
Biting
Canines- Function=
The fangs for holding
prey + tearing flesh
Premolars- Function=
Grind + hold
Molars- Function=
Grind + chew
DENTAL FORMULA- EXAMPLES
0 0 3 3
31 3 3
Pronghorn
Antelope
Mountain
Lion
3 1 2 1
3 1 2 1
MORE CHARACTERISTICS
D. Respiration- all use lungs, none use gills or skin.
E. Circulation- Heart with 4 chambers that allow
complete separation of oxygenated + deoxygenated
blood.
LOCOMOTION: PATTERNS +LIMB MODIFCATIONS
A. Ambulatory: Walk on flat feet (plantigrade) .
Example- Man, Raccoon
B. Cursorial: Legs adapted for walking +
running
1. Digitigrade: Walk on toes, as the carnivores
2. Unguligrade: Walk on toenails, as the
herbivores
MORE LOCOMOTION
C. Saltitorial : Jumping as with the kangaroo rat.
D. Arboreal: Tree climbing as with squirrels.
E. Aerial: Gliding + flying as with flying squirrels.
F. Fossorial: Burrowing as with prairie dogs +
gophers
G. Aquatic: Swimming as with the otter + beaver
THERMOREGULATION
III. Thermoregulation: homeothermic +
endothermic.
A. Smaller mammals, like the pocket mouse,
tend to avoid heat by burrowing or nocturnal
behavior or both.
B. Bighorn sheep and other larger mammals
can’t escape stress by burrowing.
IV. Reproduction: Most mammals are
viviparous.
SKULL FEATURES: PREDATOR VERUS PREY
A predator, like the fox on the left, has
forward facing eyes + sharp canines,
molars + premolars.
A prey, like the pronghorn on the right,
has eyes located on the side of the
head + flat premolars + molars with a
large surface area.
HERBIVORE, CARNIVORE, OR OMNIVORE
Herbivore: Canines inconspicuous or absent, premolars, molars are flat
with large surface area .
Carnivore: Sharp canines, premolars + molars.
Omnivore: Sharp canines, flat surfaced premolars + molars.
ANTLER
Antler formation occurs in the deer family ie. deer, moose, elk, caribou ect. With a few
exceptions( caribou), they are grown by the males and use to “battle” other males for
mating privileges. The growth of antlers represents some of the fastest know bone
development. With most species, they are replaced annually with a even larger set.
MORE ANTLER “STUFF”
High quality elk antlers can wholesale
for up to $12/ pound. A mature set of
antlers can easily weigh 50 lbs.
Amazingly, an elk can regrow a new
set of antlers in less than a year on a
diet that consists of eating plants!!
HORN
Horns differ from antlers in several ways. Horns, such as those in the Dall
sheep, Rocky Mt. Bighorn, desert bighorn + pronghorn antelope are
permanent structures, consisting of a boney core covered by a protein
sheath. Typically both the male + female possess the horns, with the males
obtaining a greater size.