1. Mammals
Chapter 15.2a

2. Characteristics of Mammals
Mammals are endotherms, vertebrates, have hair, produce milk for their young, and care for their young.
Mammals are found almost everywhere on Earth.

3. Skin and Glands Skin covers and protects the bodies of all mammals.
Skin produces hair and in some species claws, horns, claws, nails, or hooves.
The skin also has gland in it.
One gland is the mammary gland – this is where milk is produced for feeding young.
Oil glands produce oil that lubricates and conditions hair and skin.
Sweat glands remove wastes and help keep the mammal cool.
Scent glands will release substances that allow mammals to mark their territory, attract a mate, or be a form of defense.

4. Teeth Mammals will have different teeth based on what they eat.
A scientist can figure out a mammal’s diet by looking at their teeth.
Front teeth called incisors are used to bite and cut.
Canine teeth are used to grip and tear.
Premolars and molars shred, grind, and crush.
Animals that have all 4 types of teeth are omnivores – eat plants and animals.
Carnivores have large canine teeth and only eat animals.
Herbivores only eat plants so they have large premolar and molars.

5. Hair
All adult mammals have hair. It may be thick fur or just a few stray hairs.
Fur traps air and helps keep the animal warm.
Whiskers (found by the mouth) are used to sense the environment.
Whales have almost no hair – instead they have blubber to keep them warm.
Porcupine quills and hedgehog spines are modified hairs used for protection.

6. Body Systems
Mammals have a 4 chambered heart. This is a very efficient way of getting oxygenated blood to the body.
They have lungs made of many tiny sacs that increase the surface area of the lung for more gas exchange to take place.
Mammals have a brain, spinal cord, and nerves.
The digestive system is different based on the food the mammal eats. Herbivores have long digestive tracts to break down plants.

7. Reproduction and Caring for Young
All mammals reproduce sexually and will give birth to live young.
Mammal young varies based on the life it is born into. The young may be helpless or may be able to walk or run shortly after birth.
All young mammals depend on their mother for milk.