Question

how did shri rama reward squirrel for her contribution in constructing the bridge

Answer 1

Shri Ram wanted to built a bridge to get to Ravana's lanka. every animal wanted to help. there were monkeys, apes and many more. but when Ram saw squirrels also helping he became happy. he took a squirrel in his hand and then he waved his hand on it which left three lined mark on them which persists till now

Answer 2

Lord Shri Rama patted on the back of the squirrel .
As a result of this, there was an impression of Lord Rama's three fingers on the squirrel's back.
This impression is visible on the squirrel's back .