e follow the herd. The ground is now
changing, and getting quite rough; so the grass is getting scarce here
and there. The buffaloes have not enough grass all the way; so they
have to walk on a few yards without eating, till they come to the next
patch.

Some of the buffaloes are even having a bite at fresh young shrubs in
passing, as they will eat anything green, when they have not enough
grass.

But see! The buffaloes are spreading out, as there are not even enough
shrubs in one place. You can see gaps in the line of buffaloes now.
And the gaps are getting bigger and bigger! Let us watch a few
minutes.

Now the gaps are very wide, as some of the buffaloes are lagging
behind; and some are turning too much to the side in trying to reach a
mouthful from a shrub or a bush here and there.

Why, what is happening now? Some of the buffaloes cannot even see one
another now, because of the bushes between them! What are the
sentinels doing? And what is the leader doing? Suppose a tiger
suddenly comes--

But do you _hear_ that?

"Moo! Moo!"

That is the leader. He has just found out that the herd is spread out
too far; so he is calling. He is saying, "Where are you?"

"Moo! Moo!" Do you hear that answer? It comes from the sentinel on the
right, who is very far away now; but still he has heard the call. His
answer means, "Here I am!"

And "Here I am!" comes the answer also from the sentinel on the left.

"Then close up!" cries the leader.

Each sentinel moves up toward the place from which he heard the
leader's voice come. And on his way there he tells all the buffaloes
he meets to move up also. Besides, all the buffaloes hear the leader's
voice too; so they begin to close up at once.

Is not that a wonderful way of bringing up all those that are lagging
behind?

But let us watch the herd again. They have closed up now, and there is
no big gap in their line. The ground is level again.

Let us move on from thicket to thicket, and come as near the buffaloes
as we can.

What is that? See! The sentinel on the right is looking hard at that
jungle grass far away to the side. This kind of jungle grass grows
very tall, taller than a man. But why is the sentinel staring at the
tall grass? What does he see there?

Yes, there, far away, something is happening! The jungle grass is
waving gently, but just in one place! What is making the tall grass
wave like that? Is it the wind? No, it cannot be the wind! Why not?
Bec