|Why are whales mammals?|
|Question Date: 2017-10-25|
Mammals are animals that
1) require air to breath,
2) are warm blooded, so depend on a constant
supply of food to stay warm,
3) have fur or hair,
4) have females that produce milk, and
5) give birth to live young (they don't lay eggs
like a chicken).
Whales fit into this category!
You don't typically think of whales as being
hairy, but it turns out that the baby whales of
some species possess hair when they are young and
then loose it. Whales have blubber to keep them
warm so may have lost hair over the course of
evolution. But, we still consider them mammals.
Mammals are animals that give their children
milk as food. They also have a
backbone, a single bone for their lower
jaw, four-chambered hearts, a diaphragm (a sheet
of muscle and tendon that separates the body
cavity), and complex brain function. Even
though whales look fish-shaped, they have all of
these things. They also feed their babies with
milk! Since whales meet all the criteria of
being mammals, they're classified as mammals.
Whales are hoofed mammals, related to
hippos, but have evolved to live in the ocean,
losing most of their land-going traits (like
hooves). Like all mammals, they make milk, and
have three bones in their middle ears. They have
lost hair, and also give live birth.
The requirements of being a mammal are:
#1 Has mammary glands that produce milk to feed
its young (which is why they're called "mammals"!)
#2 Has a little or a lot of fur (whales are born
with a mustache!)
There are some other requirements as well, like
having a diaphragm, but those two are the most
important. Since whales can feed their young with
the milk they produce and are born with hair, they
are considered mammals. There are about 4,260
named mammal species in the world.
All mammals share two characteristics. One,
they must feed their young with milk produced
from the mother's mammary glands. Two, they
must have hair, even just a little. Whales
produce milk to feed their babies. They also have
some hair when they are young. However, most
species lose hair when they become adults. Fun
fact: baby humpback whales drink 150 gallons
of milk a day.
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