Walrus Evolution
Walrus Antecedents
There is no doubt that the design of the body for the walrus is efficient and effective. It enables them to live both in the water and on land. It also makes it possible for them to live in extremely cold temperatures where very few living creatures would be able to survive. They are closely related to the various species of seals. What may surprise you is that there is evidence to suggest that they are closely related to bears.
It is believed that anywhere from 20 million to 26 million years ago there were at least 20 different species of walrus. They were very diversified and their locations were very spread out. It is also believed that these early walrus featured a type of feeding mechanism that allowed them to squirt and to suction food. The development of tusks occurred as a part of the evolution process, and remains a part of the appearance of the walrus today.
Genetic results based on DNA have shown the Atlantic Walrus and the Pacific Walrus to be separate from each other. It is believed that the two branched off from each other anywhere from 500,000 to 785,000 years ago. This is based on the fossil remains that were found in warmer areas. It is believed that over time, the Atlantic Walrus was able to adapt to colder conditions which is when they started to live in the Arctic.
During the Pleistocene periods with the high glaciers, the Walrus species moved into the colder areas by accessing the Central American Seaway. DNA also shows that the O.R. Laptevi Sea Walrus is very isolated in terms of population. Evidence in 2009 that stems from studies involving their molars shows that they are ancestors of the Pacific Ocean Walrus.
All walrus belong in the order called pinnipeds. This order also includes sea lions and seals. The earliest known fossil records for the walrus are dates approximately 14 million years old. The information gathered leads experts to believe that during that time, the tusks didn’t exist. Instead, they had upper and lower canine teeth in place.
It is believed that they moved to the Atlantic Ocean about 6 ½ million years ago. They also believe that it has been in the last 1 million years that they entered the Pacific Ocean once again, arriving there through the Arctic Ocean. This is why many experts feel that the modern Pacific Walrus evolved from the Atlantic Ocean Walrus.
A very interesting discovery was made around the San Francisco Bay area. It is a walrus fossil that is approximately 28,000 years old. This is proof that the Pacific Walrus actually found its way to the far South during the last Ice Age. Finding out more about this process is something many experts are interested in.
There is still plenty unknown about the overall evolution process for the walrus. While there are several good theories, there is more testing and experimenting to do before they can be accepted as fact or ruled out. In the meantime, it can be very interesting to explore the various possibilities. As new fossils are found, old records reviewed with fresh eyes, and new technology comes along, the information to be gained can be very exciting.
One thing is for sure, the walrus is an exceptional creature. They have been able to stand the changes of their environment for millions of years. It is possible that evolution that has occurred for them over that time should be credited for them being able to survive all this time. Based on the fossil remains, evolution was slow but effective for the walrus.
