Odobenus rosmarus - BIO203

Adaptation

 

Photo is in public domain; originated by US Fish & Wildlife Service.

Used with permission. Photo is in public domain; originated by US Fish & Wildlife Service.            One of the distinct characteristics of Odobenus rosmarus is its prominent tusks, which are extremely overgrown canine teeth. Tusks can grow up to 90cm, normally they only grow up to 50cm but the job of the tusks is to be able to break through ice, which helps them to pull themselves up on the ice (Baker, H. 2013.). If they were not able to go onto ice they would restore to going on to land which puts them at risk of more predators. Tusks are also used in helping the walrus gain their food (look at nutrition).  Social rank can be established  according to the size of their tusks compared to the others (U.S. Fish and Wildlife Service. 1995) . Also, walruses defend themselves from  their predators, such as polar bears, as well as fighting for a mate against another walrus by using their tusks (National Geographic Society. 1996).

           Blubber is another characteristic, which categorizes walruses as a part of the pinniped order. Other pinnipeds include eardseals and true seals (Hamilton, C. and B. Kitchen). Since pinnipeds live in an extremely cold environment blubber is an adaptation which helps pinnipeds survive in the cold. Blubber  allows for the walrus to maintain its body temperature, which is known as  thermoregulation (Hamilton, C. and B. Kitchen).  Without the blubber walruses would not be able to survive the cold water temperatures. Walruses are able to survive in termperatures as cold as -31F (Sea World Parks and Entertainment) .  Much of a walruses life they are in the water in order to stay in the water longer is their blubber. To be able to stay in water without having to expend a lot of energy is to be able to float and blubber gives the walrus the ability to float, called buoyancy (Hamilton, C. and B. Kitchen). Walrus blubber is also helpful in storing energy in case there is a period of time in which the walrus is unable to find food.

         To gain access to food walruses need to reach the bottom of the sea in order to do so they need the ability to dive. In order to dive they need the ability to have a sufficient amount of oxygen to stay under the water for a long enough period of time. Walruses are able to stay underwater for up to 10 minutes (Sea World Parks and Entertainment). How are they able to survive without oxygen that long? The walrus's heart slows, blood that is oxygenated moves towards the heart and brain,  and walruses have  myoglobin that  helps to store oxygen in their muscles (Sea World Parks and Entertainment).

       Walruses have front and tail flippers that help them  through water. The walrus' front flippers can be rotated so they are able to use them to help them walk on ice or land (Baker, H. 2013.).  Other pinnipeds do not have the ability to rotate their flippers around for movement on solid group. The front flippers are also used for maneuvering the walrus in the direction they want to move in (Baker, H. 2013.).  Back flippers are used to propel themselves forward. Walruses normally swim at a speed of 4.3mph but can  go as fast as 21.7mph  (Sea World Parks and Entertainment).

   

Used with permission. Photo by Anthony Fischbach. Courtesy of U.S. Geological Survey        From this picture you can see the front flippers and how they are positioned. They are slightly turned to help them with their movement on land while their tail will drag behind them.

   

Photo by Anthony Fischbach. Courtesy of U.S. Geological Survey.

 

The walrus has many adaptations for them to be able to survive in their environment. But what does it eat to be able to survive? How much do they need? Take a look over at the nutrition tab to find out.