1. The (nine) Characteristics of MAMMALS
By Samara Nix

2. Hair…… Made out of an keratin, is thought to have evolved from scales
Hair for mammals provide insulation and water proofing (conserves body heat)
But also use a method of panting to cool down by using sweat glands
Panting releases water from the lungs which results in loss of body heat

3. Nursing….
Mammals have organs called glands that secrete various substances needed by the animals
Gland- is an organ that secretes substances inside or outside the body
Mammals have several kinds of glands
Including ones that produce saliva, sweat, digestive enzymes, and hormones
The feed there young through mammary glands
In females mammary glands secrete milk a liquid that is rich in fat, sugar, protein, minerals, and vitamins
Mammals nurse their young until they are mature enough to find food

4. Teeth
Although fish and most reptiles have teeth, their teeth are use for tearing, grasping, and holding prey
Mammals have different kinds of teeth adapted to the type of food they eat
>Pointed incisors- are used by predators to grasp and hold prey
>Chisel-like incisors- are modified for gnawing
>Canines- are used by predators such as lions and tigers to puncture
and tear flesh
>Premolars and Molars- are used for slicing, grinding, and crushing
Many hoofed animals (cows, horses, etc) have an adaptation known as cud chewing that enables them to break down the cellulose of the plant cell wall into nutrients

5. Modified limbs
This is an adaptation that enables mammals to meet there required energy levels needed
Examples: food gathering, in some groug such as primates with the opposable thumb grasping and holding objects,

6. Learning
Mammals intellegence is a result of a complex nervous system and highly developed brain
Because they know survival skills mammals are able to guard their young very fiercefully
Mammals can accomplish complex behaviors, such as learning and remembering what they have learned
Primates such as humans are the most intteligent mammals
Primates for example can use tools

7. The Diaphragm
Mammals need a high level of energy for heating and cooling their bodies, as well as for locomotion
This energy level is sustained when large amounts of oxygen enter the body and reach all the cells
One thing that enables this in mammals is the diaphragm that expands and contrast the chest cavity
Diaphragm-is the sheet of of muscle located beneath the lungs
The diaphragm seperates the chest cavity from the abdominal cavity, where other organs are located

8. Four Chambered Hearts Mammals like birds have 4 chambered hearts
So that oxygenated blood is keep away from the deoxygenated blood
this ensures that mammals receive a good supply of oxygen to support their endothermic metabolism

9. Endothermic Mammals are endothermic
They have the ability to maintain a fairly constant body temperature
Which enables them to live in almost every possible environment