All About Mammals The two main categories of living things
in the world are plants and animals. Animals are divided into two main
types: those without backbones, called invertebrates, and those
with backbones, called vertebrates. Humans are vertebrates. Your vertebrae, or
spine, runs down the center of your back. Animals in both groups are divided into smaller
groups based on their traits or characteristics. Scientists call this “classification”.
Classification helps make it easier to identify and study animals throughout the world. Scientists have classified all vertebrates
into five different groups: mammals, birds, fish, reptiles, and amphibians. You can
probably name some animals that go into each group. Each group of animals has its own unique
traits and characteristics, but some of the groups share one or more of the same traits. For
example, birds and mammals are both warm blooded and reptiles and mammals are both vertebrates.
However, they are not in the same group because they also have some differences. For instance,
reptiles and fish lay eggs but mammals do not. There is a lot to learn about each of the
five groups of animals. In this video, we’re going to focus on mammals. Mammals are
one of the largest animal groups on the earth. All mammals have backbones or spines. A human is a mammal. You are in the same animal
group as dogs, rabbits, whales, and many others. Mammals are warm blooded. That means their bodies
will always try to keep a constant temperature on the inside no matter the temperature around them.
Your body temperature averages 98.6 degrees unless you’re sick and have a fever. Other mammals' body
temperatures average between 97 and 103 degrees. But if an animal is cold blooded,
like fish, reptiles, and amphibians, their body temperature goes up and down
depending on the temperature around them. Some mammals only eat meat or plants and others
eat both, like humans do. Mammals generate their body heat through the food they eat, which
is converted into energy. Mammals must eat more food than cold-blooded animals to allow
them to maintain a constant body temperature. Have you ever jumped into a freezing cold ocean or
lake and found yourself shivering from the cold? Your body is trying to warm you up and shivering
generates little bursts of heat. Your body also tries to cool us down by sweating. Some mammals
have other ways of cooling themselves down. A dog pants and a pig rolls in the mud. The mud
protects the pigs’ skin from the sun and when the water droplets in the mud evaporate, it leaves the
pigs’ skin moist, which also helps cool it down. All mammals have hair or fur that cover their
bodies. For mammals that hibernate, like bears, lemurs, squirrels, and skunks, fur
helps keep them warm all winter long. Another characteristic of mammals is that
almost all of them give birth to live babies. This is different from fish and birds,
which lay eggs that will eventually hatch. There are only two mammals that lay
eggs -- the platypus and the echidna, which is kind of a mix between an anteater and
a porcupine. Mammal mothers nurse their young with milk that their bodies make. A newborn
mammal, like a human or a puppy or a kitten, needs a parent to take care of them after
they’re born. But in some of the other groups, the animals are left on their own
and have no one to look after them. All mammals use lungs to breathe. That’s why
whales and dolphins are considered mammals and not fish. They do not have gills like
fish and they are not cold-blooded, so they are classified as mammals.
Mammals that live on land have four limbs. That means they have two arms and two legs,
like kangaroos and monkeys, or just four legs, like horses, cows, and rabbits. There
are about 6,500 species of mammals. Rodents, such as beavers, mice, and squirrels,
make up almost half of the mammals on Earth. The largest mammal in the world is the blue
whale. It can be 150 feet long and weigh 150 tons or 300,000 pounds! That’s about the same
weight as five Statues of Liberty put together. The elephant is the largest mammal on land and
the giraffe is the tallest. The smallest mammal is called the hog nosed bat or bumblebee bat. It’s about the same size as a bee and weighs
about as much as a feather. The bat is also the only mammal that can fly. And the slowest
mammal in the world is the two-toed sloth. Mammals make up just one group of the many
types of animals in the world. Even though mammals share many characteristics, each is also
unique, from the tiniest bat to the biggest whale. Thanks for following Clarendon
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