MAMMALSI. Characteristics

A.Body covered with hair1. 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 3 1 3 3Pronghorn Antelope

Mountain Lion3 1 2 13 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 LOCOMOTIONC. 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

THERMOREGULATIONIII. 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 areviviparous.

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.