Mammalogy Lab Day 1

Medulla

center of the hair, may have patterns or be hollow

Cortex

tightly packed cells surrounding medulla

cuticle

outer layer of the hair, made up of translucent scales

patterns can be diagnostic

Pelage: Guard hairs and its function

hard, longer hair; mostly for protection and coloration

Pelage: underfur and its function

soft, shorter, closer to the skin; thermal insulation

Vibrissae and function

whiskers (longest of the 3) for tactile sensation

- encased in blood sinus that amplifies movement

Two examples of modifies guard hairs

quills (harder and backward facing barbs)

spines (softer)

both are matched with underfur

What is pelage coloration due to

pigment granules in medulla OR cortex

Frosted or Grizzled pigmentation pattern

hair with dark shaft with white tip

- ground squirrel tail or grizzly

Hoary pigmentation pattern

hair with light shaft and lighter tip (often white)

- hoary bat

Agouti pigmentation pattern

alternating bands of dark and light

- ground squirrel body

Countershading pelage pattern

light color on bottom of the body, dark color on the top of the body

- kangaroo rat

- to blend in with the ground if looking down at it and blend in with the sky if looking up at it

Concealment pelage pattern

camouflage

- giraffes

- leopards

Disruptive Coloration pelage pattern

usually stripes, SOMETIMES spots

- disrupts the outline of an animal

- zebra

- Eurasian badger

Warning Coloration pelage pattern

Using bold colors/pattens (white) like a skunk with its lifted tail

Flash Coloration Pelage Pattern

Contrasting color, often hidden but displayed as a signal

- white-tailed deer's raised tail is white when running away from predator

Melanism Pelage Variation

genetic defect leading to increased pigmentation, darker than normal

Albinism Pelage Variation

genetic defect causing total loss of pigmentation (pink eyes & nose)

Leucistic Pelage Variation

Paler than normal but not total loss of pigmentation (eyes and ears still pigmented)

Erythristic Pelage Variation

unusual genetic variation causing animal to be more orange/redish

Piebald Pelage Variation

genetic variation causing irregular patches of white, brown, and black (like a cow)

Types of pelage changes during animals life cycle

Juvenal pelage: sea lion pup is soft and white, deer is spotted

Seasonal pelage: arctic fox turns white during winter and brown during spring

Molt

shedding and replacement of old hair, fur, or skin with new growth

Aberrant

Lost pelage due to disease or infection

- mange (mites)

Horns vs Antlers

Horns: part of skull, keratin sheath over boney core

Antlers: not part of skull, can come off seasonally

Nails

dorsal compressed flat, top to bottom

Claws

dorsal laterally compressed, side to side

Hooves

just the fingernail

Keratin

key structural material that make up nails, hair, protective scales, horns, claws, and hooves