A group of living things
Even-toed hoofed mammals and whales
Artiodactyla
Hoofed mammals that include whales
Its members' last common ancestor lived about 60 million years ago.
You and even-toed hoofed mammals and whales last shared an ancestor about 95 million years ago (on 23 December, if life's history were one year).
Whales evolved from small hoofed mammals that lived on land. That is why whales sit inside this group, with hippos as their closest living relatives. Early whale fossils still have the special double-pulley ankle bone found in even-toed hoofed mammals. Scientists think one close fossil cousin was Indohyus, a fox-sized deer-like animal from about 48 million years ago.
Most land members walk on tiptoe on two main toes that form a split hoof. Hippos keep four toes on each foot, and pigs keep two small side toes on each foot, while camels have lost hooves and walk on broad pads. Land members often have short brown, grey or tan fur coats, sometimes with spots. Many land members carry paired head weapons such as horns, antlers or the short skin-covered knobs of giraffes.
Whales look very different. They are smooth and streamlined, with two front flippers, no back legs to see, and a wide flat tail that spreads sideways. They breathe air through a blowhole on top of the head, with two openings in baleen whales. Toothed whales usually have peg-like teeth, while baleen whales have no adult teeth and strain tiny sea creatures through dark plates in the mouth.
Largest animals alive today
Blue whales are the largest animals alive today, at about 25 to 33 metres long and up to about 190,000 kilograms, with females larger than males — longer than two buses and heavier than 30 elephants.
Stomachs that chew twice
Many land members have one stomach with three or four compartments that uses tiny helpers to break down plants, then brings food back up for a second chew, grinding with ridged back teeth and no upper front teeth.
Water first, hunting later
Indohyus was a plant eater that already spent much time in water, so the move into water came before the later shift to hunting seen in many modern whales.