Whales Wallpapers
Whales are cetaceans which are neither dolphins (i.e. members of the families Delphinidae or Platanistoidae) nor porpoises. Orcas (Killer Whales) and Pilot Whales have "whale" in their name, but they are dolphins for the purpose of classification.All cetaceans, including Whales, dolphins and porpoises, are descendants of land-living mammals of the Artiodactyl order (even-toed ungulate animals). Both cetaceans and artiodactyl are now classified under the super-order Cetartiodactyla which includes both Whales and hippos. In fact, Whales are the closest living relatives of hippos; they evolved from a common ancestor at around 54 million years ago. Whales entered the water roughly 50 million years ago.Whales are also threatened by climate change and global warming. As the Antarctic Ocean warms, krill populations, that are the main food source of some species of Whales, reduce dramatically, being replaced by jelly like salps.[citation needed]
