Dorudon
Encyclopedia
Dorudon was a genus of ancient cetacean that lived alongside Basilosaurus
Basilosaurus
Basilosaurus is a genus of cetacean that lived from in the Late Eocene. Its fossilized remains were first discovered in the southern United States . The American fossils were initially believed to be some sort of reptile, hence the suffix -"saurus", but later found to be a marine mammal...

41 to 33 million years ago, in the Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

. They were about five meters (16 ft) long and were most likely carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

, feeding on small fish
Fish
Fish are a paraphyletic group of organisms that consist of all gill-bearing aquatic vertebrate animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish, as well as various extinct related groups...

 and mollusks. Dorudontines lived in warm seas around the world. Fossils have been found in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

 as well as Pakistan
Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

 the eastern part of which bordered the ancient Tethys Sea.

Description

Dorudontines were originally believed to be juvenile individuals of Basilosaurus
Basilosaurus
Basilosaurus is a genus of cetacean that lived from in the Late Eocene. Its fossilized remains were first discovered in the southern United States . The American fossils were initially believed to be some sort of reptile, hence the suffix -"saurus", but later found to be a marine mammal...

as their fossils are similar but smaller. They have since been shown to be a different genus with the discovery of Dorudon juveniles. Although they look very much like modern whale
Whale
Whale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...

s, basilosaurines and dorudontines lacked the 'melon organ
Melon (whale)
The melon is an ovoid-shaped, fatty organ found in the forehead of all toothed whales , including dolphins and porpoises and believed to be used in echolocation....

' that allows their descendants to use ultrasound
Ultrasound
Ultrasound is cyclic sound pressure with a frequency greater than the upper limit of human hearing. Ultrasound is thus not separated from "normal" sound based on differences in physical properties, only the fact that humans cannot hear it. Although this limit varies from person to person, it is...

 as effectively as modern whales. Like other basilosaurids, their nostrils were midway from the snout to the top of the head.
The Dorudon calves may have fallen prey to hungry Basilosaurus
Basilosaurus
Basilosaurus is a genus of cetacean that lived from in the Late Eocene. Its fossilized remains were first discovered in the southern United States . The American fossils were initially believed to be some sort of reptile, hence the suffix -"saurus", but later found to be a marine mammal...

, as shown by unhealed bite marks on the skulls of some juvenile Dorudon.

In popular culture

Dorudon was featured in the episode Whale Killer in the BBC's documentary Walking with Beasts
Walking with Beasts
Walking with Beasts is a 2001 six-part television documentary miniseries, produced by the BBC in the United Kingdom, narrated by Kenneth Branagh. In North America it has been retitled Walking with Prehistoric Beasts, and the original Discovery Channel broadcast was narrated by Stockard Channing...

, as well as in the second part of its follow-up, Sea Monsters. They are depicted as living in groups, with their calves being the primary prey of their relative, Basilosaurus
Basilosaurus
Basilosaurus is a genus of cetacean that lived from in the Late Eocene. Its fossilized remains were first discovered in the southern United States . The American fossils were initially believed to be some sort of reptile, hence the suffix -"saurus", but later found to be a marine mammal...

.

External links

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