Identification should include

production of milk to feed their young (mammary glands)
single bone comprising their lower jaw
three tiny bones in the middle portion of the ear (stirrup, anvil, and hammer)
a diaphragm
fur or hair
a four-chambered heart
complex brain function
bodies that maintain constant temperature
various means of locomotion
well-developed senses of hearing and smell
fur or hair used for insulation, protection of the skin, camouflage, and sensory feedback.

Process/Skill Questions:

What species of mammalian wildlife are prevalent in North America?
What are characteristics of the different families of mammals that occur in North America?
What differences exist between wild species and domestic species of the same family (e.g., wolves, coyotes, and dogs; bison and cows; mountain goats and goats)?
How do bats navigate safely as they fly in darkness?
How are altricial mammals different from precocial? How does that affect development, maternal behavior, and other animal behaviors?
What does a mammal’s morphology indicate about its role in an ecological niche?
What impacts might the loss of a mammalian species have on an ecosystem?