Toothed whales are active hunters, eating fish, squid and other mammals among others. Baleen whales use their thick baleen comb to filter micro-organisms and shoals of fish from large mouthfuls. Toothed whales have one blow hole while baleen whales have two.
Whales communicate using a series of clicks and whistles, which their water medium can carry over huge distances. Some whales have also adapted this for echolocation, using an organ in the head to focus the sound and listen for returning echoes.
Blue whales are the largest animal ever to populate the planet.
Sperm whales actively hunt squid at great depths. As they eat the squid whole they need to ease their passing of the indigestible beaks by covering them in a thick liquid. This ambergris is used in perfumery to hold in the scent.
Humpback whales can be seen breaching spectacularly during the mating season. They can almost leap completely out of the water, coming down with an almighty splash.
Whales are in decline worldwide, mostly attributed to loss of available food and the actions of man. Some countries still actively hunt whales, a process called whaling, although some indigenous tribes do this in a sustainable fashion.
Whales are thought to be disturbed by naval sonar and this has been implicated in some beachings. However, recent evidence has suggested that whales can regulate their hearing, but this does not rule out discomfort from this noise.