1. How Do Walruses Find Food If They Don't Dig With Their Tusks?
It was once thought that walruses used their tusks to dig into the sea floor to find clams, similar to how a bear digs with its claws. The American public broadcaster PBS Nature introduced this old idea [4]. But when researchers watched walruses eat, the process was different. They use their snout and whiskers to locate clams. Then, they shoot water from their mouth and tongue to blow away the sand. After that, they wrap their lips around the clam and suck out the meat, or siphon it out [4].
A study looking at how the surface of the tusks wears down suggests that the tusks are just dragged through the mud on the sea floor. It is the rim above the nose that does the digging. In observations of captive walruses, the clams were pulled out by the water jet from the mouth, not by the tusks [1]. However, because the tusks are dragged along the bottom, they are not completely unrelated to eating.
If the tusks are not for digging, why are they so prominent? To understand why their tusks are so prominent, let’s look at how walruses interact.
2. How Walruses Use Their Tusks to Signal to Each Other
The tusks are actually elongated canine teeth from the upper jaw. Both males and females have them. According to Wikipedia, which is a secondary source, the tusks can reach a maximum length of about 1 meter and weigh up to 5.4 kilograms [1]. These are upper limits. Some sources say they are around 70 centimeters, and they are usually shorter. Males tend to have slightly longer and thicker tusks [1].
When a walrus is startled on the ice, it raises its head high to show its tusks. Walruses with smaller tusks usually leave the area or become quiet. The behavior of showing tusks is common. The largest, most powerful individual tends to be dominant, and this individual often has the largest tusks. Serious fights seem to happen only between individuals of similar body and tusk size [2]. Note that being "strongest" includes body size, not just tusk size.
A 1975 study by Miller is introduced as showing that tusks are more important as a sign of rank than as a tool for digging clams. AskNature states that the main role of tusks is likely social, while their role as weapons is secondary [3]. If conflicts are settled without fighting, it may reduce the risk of injury.
Are there other uses for tusks besides showing them off?
3. How Walruses Use Their Tusks to Climb Onto Ice
Imagine the movement of pulling your body up by placing your hands on the edge of a pool. Walruses are said to use their tusks to hook onto ice and help pull their bodies up [1]. Instead of hands, the teeth extending from the upper jaw act as the support.
Tusks are also said to be used to make holes in the ice and keep those holes open. This information comes from Wikipedia, a secondary source, and the original research has not been checked directly [1]. The scientific name Odobenus comes from Greek words for "tooth" and "walk." It seems to be named after the way walruses use their tusks to move their bodies [1].
The Alaska Department of Fish and Game includes one example seen by researchers. A female walrus broke thick ice like a pickaxe to help a calf that had fallen into a crack in the ice [2]. This was a personal observation reported by the source’s author and does not mean all walruses do this.
Since tusks are used every day, do they wear down or break?
4. How Walrus Tusks Wear Down and Sometimes Break
Walrus calves are born without tusks, but the tusks grow in early on [1]. However, using them causes wear. A Japanese anatomical study recorded that a 2-year-old male calf had tusks 110 millimeters long. A 19-year-old adult male had tusks that were extremely worn, with the exposed part measuring between 22 and 100 millimeters. These are values from two specimens, not an average. It seems the length of the tusks changes as they are used [6].
Tusks can also break. A study examining the teeth of wild and captive walruses found that about three-quarters of the tooth fractures found were in the upper canine teeth, which are the tusks. Fractures occurred in about 1.3% of all teeth, and about three-quarters of those were tusks. While it is clear that tusks make up most of the broken teeth, it is not known how often tusks break [5].
Even though they wear down and sometimes break, tusks are said to be used for showing status and for helping climb ice.
5. How Long Are Walrus Tusks? Measure and Compare With Photos
Try laying With an adult, measure 1 meter on a clear surface using a ruler or a tape measure held securely. This is the maximum length of a tusk mentioned in the sources. Usually, tusks are shorter, so compare this length to your own arm or leg.
Look at photos of walruses in encyclopedias or at zoos. Observe the size of the tusks and how the head is held up. If you find a photo of two walruses facing each other, compare how they are looking at each other. Think about whether tusk size or body size matters more for being dominant.