Read the text carefully and answer the question below.

The Rats and The Elephants    

    Once upon a time there lived a group of mice under a tree in peace. However, a group of elephants crossing the jungle unknowingly destroyed the homes of all the rats. Many of them were even crushed to death.

    Then taking of rats decided to approach the elephant's chief and request him to guide his herd through another route. On hearing the sad story, the elephant's king apologized and agreed to take another route.  And so the lives of the rats were saved.

    One day elephant-hunters came to the jungle and trapped a group of elephants in huge nets. Then the elephant king suddenly remembered the king of the rats. He summoned on of the elephants of his herd, which had not been trapped, to go seek help from the king and told him about the trapped elephants.

    The rat's king immediately took his entire group of rats and they cut open the nets which had trapped the elephant's herd. The elephant herd was totally set free. They danced with joy and thank the rats.

What helped the elephant's herd free?