By Amelia Meyer
Over the millennia, a number of animal species have lived and, sadly, died off. This has been due to climatic changes, human interference and, sometimes, to mysterious circumstances. Cetaceans and, more specifically, whales are no exceptions. The group of extinct, primitive whales are classified in the suborder Archaeoceti. Today, we know of around 140 cetacean species that are already extinct. Studying these and learning more about them provides an interesting foundation on which to understand the whales that are still in existence. It also explains much about the condition of the earth and its waters millennia back.
A drawing of Pakicetus inachus, a whale ancestor.
Skeletons of the Eocene archaeocete whale Dorudon atrox.
This file is licensed under the Creative Commons Attribution 2.5 Generic license.
These extinct whales include:
FROM THE PROTOCETIDAE FAMILY
The Himalayecetus subathuensis
This fossil is, to date, the oldest one ever found, believed to be approximately 53.5 million years old. It was found at the foot of the Himalayan Mountains in northern India, which was once under water. This whale was small and had somewhat seal-like characteristics.
The Pakicetus inachus
This fossil was dated at about 50 million years old and is, as such, the second-oldest known example of early whales. It measured about six feet (the average height of a human male) in length and had nostrils on the tip of its nose as well as a pointed tail with no tail fin. Fossilised remnants were found in Pakistan.
FROM THE DORUDONTIDAE FAMILY
The Dorudon atrox
This whale measured about 20 feet (or six metres) in length and had a distinctively pointed snout. It rear limbs were extremely short (only about 10 centimetres long).
This whale’s appearance was more like a serpent, but it had similar proportions to modern-day whales. It also measured about 20 feet in length. The remnants of these ancient animals were found along the east coast of North America.
Fossil of Squalodon, an extinct whale at Musee d’Histoire Naturelle, Brussels.This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
FROM THE BASILOSAURIDAE FAMILY
The Basilosaurus cetoides
These whales began to resemble modern whales more closely. They were large, and also displayed the snake-like characteristic to their body (as opposed to looking more like a seal). They are dated to between 35 and 40 million years ago and grew to mammoth lengths of up to 25 metres (or more than 80 feet). There were no hind legs and their rear flippers were in the process of shrinking.
FROM THE SQUALODONTIDAE FAMILY
This toothed whale looked very much like our modern dolphins. It was about 2.3 metres long (or 7.5 feet).
The Squalodon had a long snout, which was distinctly pointed as it tapered to the front. Its mouth was filled with serrated teeth.
While these animals no longer exist, they do provide a very clear and important warning to us. If we do not take active measures to protect the whale species (as well as other cetaceans) that we now enjoy, they are in the very real danger of joining these extinct species. This would be tragic when we consider the value that they present to the ecosystems they occupy, and their beauty that we enjoy.
For more information, please view: http://www.nmfs.noaa.gov/