Protocetids existed around 48 to 35 million years ago and were considered to be the first whales to leave the Indian subcontinent and spread through all shallow subtropical oceans throughout the world.Ĭompared to the Remingtonocetids the protocetids nasals were much larger and located about halfway up the snout. This species did not ingest fresh water so they had little to no dependency on fresh water. They had short legs as compared to the remingtonocetids and swam in shallow marine deposits. Remingtonocetids appear to have existed between 49 and 43 million years ago. It seems as though they hunted in ways very similar to modern-day crocodile and ate raparian prey and fish. This species had long limbs and a tail (without flukes) and where able to travel on both land and water, however they where not particularly great at either. AmbulocetidaeĪmbulocetus natans lived about 48 million years ago and appear to have been amphibious resembling the appearance of a crocodile. They had unusually thick bones which seem to have been a way to make it easy to float on water rather than swim underneath the ocean. Pakicetids teeth are also similar in shape and design of the fossil whale. Pakicetids fossils were first discovered in pakistan in 1979 and appear not to have been designed for swimming due to their legs and short hands and feet. Pakicetids are hoofed mammals that lived around 53 million years ago and are considered the earliest form of whale acnestory with indohyus being the closest sister family. The sister group of the (pakicetidae) indohyus share several characteristics with cetaceans (whales) including an unusual characteristic only found between the two species known as an Involucrum (A layer of new bone growth outside of existing bone). Early ancestors IndohyusĪ small deer like creature that lived about 48 million years ago and resembles a small deer, but was only about the size of a raccoon. This article will guide you through some of the most important stages in evolution for the cetacean species and educate you about their beginnings and how they ended up becoming the marine mammals they are today. There have also been a number of archaeological findings that have brought additional insights into the history of these marine mammals.įor ages the evolution of whales transforming from from land animals to sea creatures remained a mystery until a recent discovery in Pakistan as well as in other areas which revealed several different evolutionary cycles indicating the changes in their physiology from land animals into their current state as marine mammals.įrom this gathered information cetaceans are believed to have evolved through several different forms of species over the course of millions of years as evolution continued to evolve these marine mammals as a way to adapt to anticipated threats in order to improve their survivability on earth. In fact even today there are several factors we can look at that help us identify their ancestral beginnings such as their need to breathe air, the bones in their fins which resemble the limbs of their land dwelling ancestors and the design of their spines which appear to be designed originally for running (not swimming). Information gathered over the centuries has helped us bring light to their evolutionary past which shows that these marine mammals originated from their land baring mammal ancestors and over the course of millions of years these animals evolved into the species we now know today as cetaceans or whales, dolphins and porpoises. Whales are part of the cetacean species which is made up exclusively of whales, dolphins and porpoises.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |