Modern whales are fully aquatic mammals, i.e. they cannot live outside of water. Like other mammals they breathe air, give birth to live young that they nurse, and have hair in early stages of their development. Scientists usually use the word "whale" as a synonym for the order Cetacea, which includes dolphins and porpoises as well as whales. Modern cetaceans can be divided into two groups: mysticetes, or baleen whales, and odontocetes, or toothed whales (the group that includes sperm whales, dolphins, and porpoises). Cetaceans arose in the Eocene, approximately 50 million years ago and became fully aquatic in a few million years. Whale origins are well known from fossils. They document the transition from land to water and tell one of the most exciting stories in evolution.
Characters of modern and fossil whales
Characters of modern whales (may or may not be present in fossils)
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Dr. Thewissen stands next to the skeleton of a killer whale in Senckenberg Museum (Frankfurt, Germany) |
All pictures on these pages are public access, although the source must be identified in publication.
Ambulocetidae
| Basilosaurids and
Dorudontids | Bibliography | Hearing
| India |
Locomotion | Mysticetes
| Odontocetes | Osmoregulation
| Pakicetidae |
Pakistan | Protocetidae
| Remingtonocetidae | Whale
| Whale Origins!
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