[gentle music]
- Announcer: The Wisconsin School of the Air
presents Robert S. Ellarson,
University of Wisconsin Extension specialist
in wildlife management
in The Wonderful World of Nature.
This series of programs designed for in-school viewing
by children in grades 5 through 9
is televised each Monday afternoon at 2 o'clock
by University of Wisconsin Television.
Now, Robert Ellarson and The Wonderful World of Nature.
- Hi, boys and girls.
Today, we're going to take up a topic
that has always seemed to be one of the most interesting
in this wonderful world of nature of ours.
We're going to be talking about the adaptations of animals.
Now, adaptations are specializations of animals
which enable them to do a better job
of living in their particular habitat.
Now, do you all remember that word habitat?
We talked about it last week, you know.
Habitat is the environment or the place
in which animals live, and we talked about a number
of different kinds of habitats last week.
We talked about marshlands and we talked about woodlands,
and we talked again about prairie lands or grasslands.
Now, what do we mean by an adaptation?
Well, an adaptation is a specialization
of a particular part of an animal, which enables it
to fit more perfectly into its chosen environment.
Now, in the case of muskrats,
muskrats are animals which live in the marshlands.
The marshlands have water,
and they have ground which is very wet.
They have a variety of vegetation
of cattails and sedges.
And the animal that lives in this type of habitat
is the muskrat.
If you will take a look here now at this animal
which I have in my hand, this is a study skin of a muskrat.
A study skin is actually a skin of the animal,
which is stuffed to preserve the skin.
It is not mounted in a particular lifelike fashion,
but it is merely put up in this way to preserve it
so that we can study it.
Now, what are some of the adaptations of this muskrat
which enable it to do such a good job
of living in its marshland environment?
Well, first of all, we know that the muskrats live in water.
Actually spend a great deal of their time
right in the water and beneath the surface of the water.
So it is necessary for them to keep dry and warm
while they're in the water.
And the coat of the muskrat is the part of the rat that
is specialized and enables the animal to live in the water.
The coat is made up of two kinds of hairs,
a rather long, stiff outer hair
which protects and keeps dry the inner hair.
And the inner hair is very fine and soft
and is what we usually call fur.
And this fur keeps the animal dry and warm,
even though it is beneath the surface of the water.
Now, what are some of the other specializations
or adaptations of this animal?
Certainly the animal does a good bit of swimming.
And if we look at the feet of the muskrat,
we find, first of all, that the hind feet are very large
in comparison with the front feet.
Notice that they are three or four times the size of the...
The hindfeet are three or four times the size
of the front feet.
And the hindfeet have an edging of stiff hairs around them,
which increase the surface of the foot
and enable the rat to do an excellent job of swimming.
When the muskrat swims, the forefeet are not used,
but rather the hindfeet are used to paddle exclusively.
Now the tail is also specialized.
You can see here that the tail
is somewhat flattened.
And this flattened tail acts as a rudder as the animal swims.
In other words, the animal, the muskrat steers with its tail.
Now, going from this marshland environment,
we can probably next go to the woodland
and study some animal,
an animal which is adapted to living in a woodland.
And the animal I have selected for this is the flying squirrel.
This picture of flying squirrels shows the animal
in their natural habitat, and you can notice
off to the left of the picture, a flying squirrel gliding
from one tree to another.
Notice the large folds of skin
between the front leg and the hind leg,
which act as a regular parachute.
Notice also how the animal's tail is acting as a parachute
as the animal glides from one tree to another.
It doesn't actually fly, but rather sails
from one place to another.
Now, here is a skin of a flying squirrel.
These tiny little squirrels are the smallest
of all of our squirrels.
This is the full-grown flying squirrel.
And now, let's take a look at some of the adaptations
of this flying squirrel.
First of all, between the hindfeet and the forefeet,
we find a little fold of skin,
which in the live animal can be expanded
and spreads out to increase the body surface of the animal
and allow it to glide.
Also, another specialization is to be found
in the animal's tail.
Notice that the flying squirrel has quite a different tail
from the regular red squirrel and gray squirrel
and fox squirrels.
Notice how flat and thin the tail
of the flying squirrel is.
Also notice that the hair is very stiff in this tail,
and this tail acts as a parachute and also as a rudder
as the animal sails from tree to tree.
The feet of the flying squirrel too are specialized,
and the long toes have very sharp claws,
which enable the animal to climb the trees
with a great deal of ease.
So this little flying squirrel is particularly adapted
to a life in the trees.
Now, the next animals that I would like to talk about
are some animals that are adapted to living their life
beneath the surface of the ground,
particularly in the grasslands.
The first animal I'd like to talk about is this one here,
and this is a pocket gopher.
It's an animal, a rodent,
that is found in the northwestern part of Wisconsin
in the sandy soil areas.
If we look at the skin of a pocket gopher,
we find that it is rather a medium-sized little animal,
about 8 inches long,
a very heavy-bodied animal with short legs
and rather a short tail.
The eyes of the pocket gopher and the ears are rather small.
I don't know whether you can see them here.
Here is the eye and the ear.
But the eyes and ears of this animal are quite small
because the animal spends most of its life in burrows
beneath the surface of the ground.
It feeds on the roots and stems of plants that it finds there.
Now, one of the most amazing adaptations of the pocket gopher
is to be found in the animal's forefeet.
Notice how very short the forefeet of this animal are.
Notice how large the feet are
and what very long, sharp claws it has.
These long, sharp claws and short, powerful forelegs
enable the animal to dig through the soil
with tremendous rapidity.
It can travel at a, very rapidly digging its way
through the soil.
In contrast, look at how small the hindfeet
of the pocket gopher are.
In the muskrat, you recall, the forefeet were small
and the hindfeet were large.
In this case, just the opposite is true.
And of course, the reason for this is that
this animal uses its forefeet to dig its burrows.
Another interesting adaptation of the pocket gopher
and the adaptation which gives the animal its name
are the pockets.
On either side of the animal's head
are two little fur-lined pockets,
and I'm going to run this piece of paper down
into these pockets so that you can see where they are located.
Right there and right here.
These pockets are quite deep, and they are used by the animal
to carry food in, and the animal also uses them
to carry soil from its burrows up to the surface of the ground.
Now, the next animal that I'd like to talk about
is another one which is also adapted to a life underground.
And the adaptations of this animal are even more extreme
than that of the pocket gopher.
The picture you see is that of a mole in its burrow,
and as you see the picture here,
the animal is feeding on an earthworm in its burrow.
If we look closely at this skin of a mole,
it's rather difficult to tell just which end is which.
That is because the animal does not have an external eye.
The eyes are completely closed, as are the ears.
And, but it does have a rather short naked nose.
The other end of the animal, we find a rather short naked tail.
So it's difficult to tell just whether this mole
is coming or going.
If we turn the animal over, we can see
that the forefeet of the mole are certainly adapted
to its way of life beneath the surface of the ground.
Because these two large forefeet are regular little spades
or shovels, which enable the animal to dig through the soil
almost as fast as it can walk on the surface of the soil.
Notice too that the hindfeet of the animal are quite small.
Now, still another adaptation of the mole is to be found
in the animal's fur.
It's a beautiful silvery fur, and it is interesting
because it is possible to smooth this fur
both forward and backward.
And this adaptation allows the animal
to move both ahead and backward in its burrow
without picking up a lot of soil in its fur,
and in this way, this enables it to keep clean.
Now, I have still one other animal
that I'd like to show you.
A couple of weeks ago, I was out in the woods, and I happened
to run across a rather small opossum out wandering around.
And I decided to pick him up and bring him along
and show him to you boys and girls
to show you what some adaptations
on a living animal look like.
And here is our friend the opossum.
The opossum spends part of its life living in trees.
And so it has a number of adaptations which enable it
to get about in trees.
First of all, take a look at the opossum's tail.
Notice how this opossum winds its tail around my finger.
This is what we call a prehensile tail,
or a tail that the animal can use to balance itself
or to hold onto a branch or limb as it climbs in a tree.
The forefeet of the opossum, the paws are almost hand-like
with long, sharp nails, which enable the animal to climb.
The most interesting thing about this animal, though,
is to be found in its hindfeet.
The hindfeet of the opossum
look almost like your hand and my hand.
Notice that it has these four fingers and a thumb.
And this is what we call an opposable thumb.
In other words, it is a thumb
that works against the fingers in this fashion.
And so this allows the opossum to grasp branches and limbs
as it climbs about a tree.
And these are the adaptations which enable the opossum
to live in trees much more easily than an animal
that does not have them.
Now, in conclusion today,
what can we say about these adaptations?
Well, these adaptations are specializations
which allow an animal to live in a particular type of habitat
and do a very good job of it.
But they are specializations,
the animal becomes so specialized
that it has a great deal of difficulty
living anywhere else.
For example, our little friend the flying squirrel,
if it did not have trees to live in
and was forced to live on the ground,
certainly would not live very long
because it cannot travel very fast
and would soon fall prey to any of the predators.
The same is true of the pocket gopher and the mole.
If they were forced to live on the surface of the ground
rather than beneath the ground,
they too would not live very long.
So these adaptations specialize the animal to such an extent
that it must have a particular type of habitat
if it is to be successful and is to live.
So long for now, boys and girls.
[gentle music]
- Announcer: Each Monday afternoon at 2 o'clock,
the Wisconsin School of the Air presents Robert Ellerson,
University of Wisconsin Extension specialist
in wildlife management
in The Wonderful World of Nature.
This series of programs is designed for in-school viewing
by children in grades 5 through 9.
Next Monday at 2:00, our television classroom
will again view The Wonderful World of Nature,
and we invite you to join us then.