Ambulocetus

The Ambulocetus was a genus of animals represented by a single species that inhabited our planet a short time ago in comparison with the dinosaurs.

Its name literally means “walking whale” and it is a huge prehistoric semi-aquatic animal that inhabited shallow water areas where it could walk and swim. It has been classified among the cetacean mammals.

They inhabited during what we know as the Cenozoic Era, which appears after the Mesozoic Era (that of the dinosaurs). The Cenozoic Era is quite wide and is divided into several stages, the Ambulocetus inhabited in the Paleogene period.

This genus is said to be the ancestors of today’s whales and to have a physical appearance very similar to today’s crocodiles. It is also speculated that it would have attacked like the crocodiles, waiting for its prey on the shores.

If you find the story of this animal fascinating you should know that below you can find extensive and detailed information about the Ambulocetus. Stay with us and learn more about these curious ancestors of the legged whales!

Taxonomy of the Ambulocetus

  • This prehistoric animal belongs to the kingdom of Animalia.
  • Ambulocetus is classified within the division or phylum Chordata.
  • The class to which this genus belongs is Mammalia.
  • The order of Ambulocetus is Cetacea.
  • The suborder in which this extinct animal is classified is Archaeoceti.
  • Ambulocetus belongs to the family Ambulocetidae.
  • It is classified within the subfamily Ambulocetinae.
  • The genus is the name by which we identify this animal, Ambulocetus.
  • This genus has only one discovered species, Ambuloceuts Natans.

History of the discovery

The first remains of this creature were found in 1994, in Asia, more precisely in the Sulaiman mountain range, located in Pakistan. In a rocky terrain where the ancient Tethys Sea used to be.

Searchers of prehistoric vestiges from Michigan carried out an excavation in which they found very complete fossil remains that would correspond to the hind limbs, vertebrae, ribs and a whole skull of a prehistoric mammal.

This discovery was somewhat disconcerting for its discoverer Johannes GM Thewissen, since this animal had legs similar to those of a land animal but these were webbed, which made swimming easier.

In addition, Thewissen discovered in the fossil remains that the bones of the ear were very similar to those of today’s whales, so he was quick to relate this creature to whales.

Thewissen called this animal Ambulocetus natans.

Later on, it has been proven that the Ambulocetus was a whale with legs, so it was considered one of the links in the evolution of the whale that started with the Pakicetus.

Since this discovery and until now, no more fossils have been found. However, skeletons of Rodhocetus and Basilosaurus have been found, which are species that evolved from the Ambulocetus.

The life of the Ambulocetus on planet Earth

This animal inhabited the planet Earth approximately 50 to 48 million years ago, which takes us to the time of the Eocene, in the Upper Kuldana Formation.

Its habitat was mainly marked by the warm waters of the Tethys Sea, a prehistoric ocean that existed about 250 million years ago, separating the African continent from the Middle East.

Later this sea would disappear when the tectonic plates of India slid against the plates of Eurasia, which caused the mountains of the Himalayas to increase their size little by little, gradually fading this ocean.

Regarding their diet, we must take into account the shape of their teeth, which were long and sharp, leading us to deduce that they were carnivores. It is believed that their diet was based mainly on fish and small animals that lived in the water.

The Ambulocetus had a great bite force, so some researchers point out that it fed on large fish, and it may have even frequently attacked large prey that came to shore to drink water, as some lizards do today. Although this is not proven, it is simply a theory that has been formulated.

Regarding the behavior of the Ambulocetus during its stay on this planet you should know that it was not as good a swimmer as other aquatic animals of its time, so it inhabited shallow waters where it waited for its prey to attack it by ambush.

The investigations carried out so far indicate that he had a life between land and water, his modus vivendi is compared to that of sea lions or even crocodiles, in fact some point out that he hunted like crocodiles waiting for their prey on the shore.

In its habitat it had to compete with other lizards and large carnivorous fish, perfectly adapted to the water, such as the Otodus obliquus shark.

General characteristics of the Ambulocetus

This animal could reach a length of approximately 3 meters, besides it reached a small height of only 50 centimeters and as for its weight it was around 120 kilograms.

Starting with the skull, this indicated that it could hear very well under water, the large space for the temporal muscle (the one that helps to close the mouth), indicates that it had a very powerful bite, as we have already mentioned.

Ambulocetus’ eyes were located on the top of his head and partially facing upwards, which could have helped him to locate his prey while submerging his body.

He was adapted enough for swimming, had a flattened tail and was full of muscles. As for its hind legs, they were long and wide at the end, so they functioned as flippers.

It is believed that he swam as otters do today, helping himself from his legs backwards, arching his spine and moving his tail up and down. However, other researchers believe that it swam like dogs do, using its tail as a rudder.

Most paleontologists think that the Ambulocetus could have had a life on earth, although it was probably slow and clumsy. The paw bones were strongly connected to the base of the spine and the pelvis, showing that it supported all its weight on the ground, as sea lions do.

The extinction of the Ambulocetus

The extinction of this animal is marked by two reasons, the first is believed to be because of the strong competition it had with other animals in its ecosystem, a battle in which it was not a winner.

On the other hand, in that era a great event happened that changed the lifestyle of all the animals that lived at that time, an event that was called Grande Coupure, which consisted of the union of the European and Asian continents, in addition to the rapprochement of the African continent.

Continental movements that marked the disappearance of the Tethys Sea, place where this animal lived.

In addition to these factors, this change also increased the Antarctic current, which caused a progressive drop in temperature, forming polar ice caps in Antarctica and favouring the formation of ice on the bottom of the oceans.

All this caused a decrease in the level of the seas and the cooling of them. This marked the end for many warm water marine species.

It should be clarified that this mammal, seeing its habitat destroyed, had to diversify to other sea beds, which surely marked the beginning of the evolution to other species, more specialized in the aquatic world.

Some curiosities about the Ambulocetus

  1. The Ambulocetus appears in the first chapter entitled “New Dawn” in the BBC’s Walking with Beasts series.
  2. In the book “Ice Hunt” by James Rollins the Ambulocetus natans are mentioned, in the novel they are called “Grendel’s” and they live around an iceberg. They also appear in the book “Evolution” by Stephen Baxter.
  3. This animal is also present in the anime “Cage of Eden”, attacking some characters that are at the seashore.
  4. The Ambulocetus is also featured in the National Geographic documentary “Evolution of Whales”.