Details: This poster shows a whale tail through a hole in a piece of ice. In the bottom right it says Save Our Planet .
Whales are marine mammals of order Cetacea which are neither dolphins nor porpoises. They include the blue whale, the largest living animal. Orcas, colloquially referred to as killer whales , and pilot whales have whale in their name but for the purpose of classification they are actually dolphins. For centuries whales have been hunted for meat and as a source of valuable raw materials. By the middle of the 20th century, large-scale industrial whaling had left many species seriously endangered. Like all mammals, whales breathe air into lungs, are warm-blooded, feed their young milk from mammary glands, and have some hair, although very little.