What is the hole on top of Dolphin for?

The hole on the top of the dolphin is the blowhole.

Dolphins breathe through their blowhole, which can empty and refill the lungs of a dolphin in one fifth of a second.

The blow is explosive and the air reach speeds of up to one hundred miles per hour.

A nerve mechanism alert the dolphin when the blowhole is out of the water and it can blow the air and take new air again.

Strong muscles close the blowhole when dolphins dive into the water to avoid drowning.

Links to other pages in this site

Why Are Dolphins Endangered Animals?
What Do Dolphins Eat?
What Kind Of Water Do Dolphins Live In?
Where Do Bottlenose Dolphin Go In The Summer Months?
How Do Dolphins Help People?