Some whales have one blowhole and others, like this blue whale, have two. Unlike humans, whales breathe voluntarily. That means they choose when to take a breath. This is important because whales can't breathe underwater. They surface every few minutes to blow out a mixture of water and air and take in a breath of fresh air.
Whales have bellybuttons, too.
Just like you and me, whales have bellybuttons. Like all mammals, they give birth and nurse live young. The bellybutton is what remains of the umbilical cord . Like all whales, the blue whale is a mammal rather than a fish. It is warm-blooded, has lungs rather than gills, and nourishes its young with milk.