Theory:

Narrator: The bushes rustled a little in the forest and Father Wolf dropped with his haunches under him, ready for his leap. Then, if you had been watching, you would have seen the most wonderful thing in the world – the wolf checked in mid-spring. He made his bound before he saw what it was he was jumping at, and then tried to stop himself. The result was that he shot up straight into the air for four or five feet, landing almost where he left ground.

Father Wolf: Man! (Snaps) A Man’s cub. Look!

Narrator: Directly in front of him, holding on by a low branch, stood a naked baby who could just walk – as soft and as dimpled a little atom as ever came to a wolf’s cave at night. He looked up into Father Wolf’s face and laughed.

Mother Wolf: Is that a Man’s cub? I have never seen one. Bring it here.

Narrator: A wolf accustomed to moving his own cubs can if necessary, eat an egg without breaking it, and though Father Wolf’s jaws closed right on the child’s back not a tooth even scratched the skin as he laid it down among the cubs.
Explanation:
 
Something was indeed coming towards the wolves. The bushes were moving as if something was pushing through the forest.
 
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Bushes rustled a little as if something was pushing through
 
As it neared, Father Wolf readied himself to attack the visitor. The wolf jumped up straight into the air for four or five feet, but when he saw who the visitor was, he controlled his movement, stopped his pace, and landed almost where he started. So, more or less, it seemed as if the wolf had a high jump rather than a long jump.
 
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A profile of jumping wolf; Father Wolf  tried to stop himself after 2nd stage

It was a child! 'A Man's cub', called out Father Wolf. The visitor was indeed a baby boy. A toddler who could barely walk came through the bushes. He looked so soft and had dimples on his face. Holding onto a low branch, the boy stood naked and looked up into Father Wolf's face and laughed.
 
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A Man's cub (a baby boy) came through the bushes

When Mother Wolf heard her husband say that it was a Man's cub, she asked him to bring the child to her since she hadn't seen a human baby before.
 
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Mother Wolf asks her husband to bring the Man's cub to her
 
Father Wolf carried the boy in his mouth and laid him near his cubs. Though the wolf’s jaws held the child’s back, not even a tooth scratched the skin.
 
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A wolf transports its cub using its mouth

Animals such as wolves transport their young ones using their mouths. While their teeth are quite sharp and can tear into any flesh in a matter of time, they also know how not to use them. For instance, though they carry their cubs using their mouth, they do it so that not even a scratch appears on the little one. As the narrator says, they are capable of eating an egg without breaking it.
 
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A wolf's mouth displaying its teeth
 
Important!
Click here to watch how animals carry their little ones!
 
Meanings of difficult words:
 
S.No
Words
Meanings
1
RustledThe sound made by the movement of things such as leaves or paper
2
Haunches One of the back legs of an animal with four legs
3
LeapTo make a large jump or sudden movement, usually from one place to another
4
CheckedTo prevent something from increasing or continuing
5
SpringTo move or jump quickly and suddenly towards a particular place
6
Checked in mid-springTo stop in the middle of a jump
7
Bound To move quickly with large jumping movements
8
Shot up To grow or rise rapidly
9
Snap
To say something suddenly in an angry way
10
AccustomedTo become familiar with something
11
Jaws The mouth, including the teeth
Reference:
State Council of Educational Research and Training (2019). Term-3 English Standard-6. The Jungle Book. (pp 116 - 121). Published by the Tamil Nadu Textbook and Educational Services Corporation.