What Is a Mammal?

What Is a Mammal?
By Dawn Lambros

Believe it or not, many people really don't know what a mammal actually is. There are a number of identifying factors that define a mammal from a non-mammal. They are some of the most beautiful, amazing creatures on our planet Earth and come in all shapes and sizes - from armadillos to whales, including human beings. Mammals share very distinct similarities that might surprise you.

Mammals belong to the animal classification (class) known as Mammalia. They share specific characteristics that differ from other animals. For one, nearly all mammals are warm-blooded and are live birth bearers, meaning they give birth to live young rather than laying eggs that need to hatch.

Earth's female mammals are the only creatures on our planet that make milk for their young. The milk is produced through the mother's mammary glands, which are generally located on the chest to upper groin area. The milk is very rich in vitamins and special nutrients that are crucial to a baby animal's needs.

Unlike our cold-blooded reptile friends such as snakes and most lizards, who require sunlight to warm up, mammals are virtually ready to start the day instantly. Their bodies make enough heat to hold a consistently warm temperature.

While most mammals live on land, Bats (yes, bats are mammals) have taken to the skies! Marine mammals such as whales and manatees (or sea cows) live in our oceans.

Scientists believe that large marine mammals like whales and dolphins have very evolved brains, much like those of humans. They are able to communicate, follow instructions, and intelligently figure things out. Mammals also have larger, more well-developed brains than other animals, and most have good memories and are able to learn new things. This means that mammals can learn to survive in new places and situations if necessary, which is formally referred to in wildlife science as adapting.

Another characteristic found in mammals is in their specialized teeth. The teeth are replaced just once during an individual's life, which is known as diphyodonty. The first teeth of a mammal are referred to as the milk teeth, much like humans.

Mammals such as Polar Bears have a hairy type of fur, especially on the bottom pads of their feet. This helps keep them warm, and also aids them in gripping icy surfaces. The thick hairs of the polar bear's waterproof fur coat are actually hollow and buoyant. This combination helps hold in the animal's body heat, and also helps them to float easier in water. Most mammals have a fur coat with two distinct layers; an undercoat of shorter dense hair and an outer coat of longer, thicker, stiffer hairs. Mammals are the only animals with hair or fur that protects against the elements - heat, cold, wind, rain, bacteria, and even infection.

It is believed that well over 5000 species of mammals exist within approximately 25-30 different classifications (classes). Scientists continue to disagree over the exact numbers, and on how some animal orders relate to others.

As our wildlife kingdom continues to grow and unfold, we always hope to discover new animal species and to protect the ones already integrated into our world. It is a beautiful and ongoing journey.

Find out more about Animals at AnimalWeb

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