I've always been fascinated by whales! When I was young, I had a recording of humpback whales singing that I used to listen to constantly. (You can listen to this sound here.) Their songs sound so sad and lonely to me but, in reality, it appears that they sing to communicate with each other.
That's a humpback whale in the picture to the left.
Here are some rather surprising facts about whales.
1. The blue whale is the largest animal that has ever lived on the earth - including the largest dinosaurs! It's heart is the size of a compact car!
2. The gray whale migrates more than 10,000 miles each year, the longest migration of any mammal.
3. Orcas, which are commonly called killer whales, are actually not whales at all. They are members of the dolphin family.
4. Whales are cetaceans - which makes them mammals not fish. Dolphins and porpoises are cetaceans, too.
5. Whales rest half their brain while they sleep! One half is awake at all times. Unlike most mammals, whales are not involuntary breathers so half their brain needs to stay awake to keep them breathing - and to alert them to danger.
Facts were found on the following sites:
Image obtained here