The walrus is one of the most iconic marine mammals in the world. They are easily distinguished by their large size, whiskers, and mustache. So just how old do walruses get?
The walrus is a long-living marine mammal. In some circumstances, they can live to over 40 years old. They can be found in both captivity and the wild. However, there are numerous threats to the walrus lifespan including predators, climate change, and infections.
Keep on reading to find out more about the differences in walrus lifespans, and the main dangers posed to them. You will also be introduced to which animals are confident enough to hunt the walrus.
How Long Do Walrus Live?
Walruses can live up to 40 years old in the wild1 (sources: WWF and Seaworld). Walruses tend to live longer in the wilder than they do when kept in captivity2 (source: Wikipedia). However, this does not mean that there are a reduced number of dangers posed to walruses in the wild. The main causes for walrus mortality are infections, conflicts between other walruses, and predation3 (source: F.H. Fay, North American Fauna, Vol. 74 (74), pp.1–279, 1982).
For example, walruses can be killed in the wild by their natural predators. Young and injured walruses are sometimes targeted by polar bears and orca whales. Another major threat to wild walrus populations is humans hunting them for subsistence and for commercial gain. This has led to the near-extinction of entire populations in some areas4 (sources: Arctic Museum & Arctic Studies Centre, Bowdoin College, The Polar Bear Programme, 2015, T.Pao, Arabic and Chinese Trade in Walrus and Narwhal Ivory, and DEFRA).
Another example of a threat to walrus longevity is stampeding. As walruses often congregate in groups – sometimes in the thousands – then stampedes pose a danger to weak walruses. Stampedes can occur when walruses are frightened or startled by a threat5 (sources: Seaworld and Alaska Department of Fish and Game). For example, a walrus can become anxious when a polar bear or a human is present6 (source: Center for Biological Diversification). These stampedes can increase the mortality of walrus calves7 (source: Seaworld and Alaska Department of Fish and Game).
There are also larger problems that walruses are facing. One major concern is global warming which is causing the sea ice to melt. Walruses depend on sea ice to rest in between dives. This makes rising temperature a concern as it means that walruses are spending less time resting – therefore could be exerting more energy8 (sources: C.V.Jay, et al, Polar Biology Vol. 34, pp.1065–1084, 2011).
How Long Do Walrus Live in Captivity?
Walruses typically live for around 20 to 30 years in captivity9 (source: F.H. Fay, Mammalian Species, Vol. 238, pp.1-7, 1985). This suggests that walruses generally live for shorter periods of time in captivity, than in the wild. However, there are exceptions to this as the oldest known walrus to die in captivity was aged 40 years old10 (source: N.L Times, 2014).
The shorter lifespan of walruses living in captivity is suggested to be for a couple of reasons. When walruses are placed in artificial surroundings, sometimes their behavior changes. For example, the relationship between a mother walrus and its calf can diminish. This leads to the calf experiencing malnutrition which could possibly lead to poor growth and a higher chance of early death11 (source: F.H. Fay, Mammalian Species, Vol. 238, pp.1-7, 1985).
Another reason why walruses may have a shorter lifespan when kept in captivity is that they are more susceptible to tusk infections and eating objects they should not12 (sources: Museum of Zoology, University of Michigan and Zoodent). It is these tusk infections and lesions which could play an important role in walrus mortality, thus captive conditions should remain high to reduce this13 (source: J.N.Winer, et al, Journal of Comparative Pathology, Vol. 155, Issues 2–3, pp.242-253, 2016).
How Can You Tell How Old a Walrus Is?
You can tell how old a walrus is by looking at its teeth. The teeth are made of dental material. This material grows as the walruses get older. This growth produces layer groups. Scientists can analyze these layers of dental material and determine the age of the walrus. It is usually the cheek tooth that is used for age investigations14 (source: Seaworld). Sometimes older adult walruses have more scars from more encounters with their predators15 (source: WWF).
When Do Walruses Mature?
Male and female walruses mature at different ages. Female walruses become sexually mature at around 6 to 7 years old. Male walruses become sexually mature at 8 to 10 years old. This means that female walruses mature quicker than male walruses. Further, male walruses become more successful breeders when they are 15 years old. This is because it is only at this age that they can compete with the older adult male walruses16 (source: Alaska Department of Fish and Game).
Do Walruses Have Any Predators?
Yes, walruses do have predators. The two main predators of walruses are the polar bear and the orca whale. Both of these predators would usually hunt young walruses, or injured adult walruses. Sometimes even adult male walruses are hunted. However, walruses are not the main diet of polar bears or orcas, therefore walruses are only hunted when food is scarce17 (sources: BBC Studios and The Polar Bear Programme, 2015).
Another large threat to walruses is humans. Humans have hunted walruses since the tenth century, and some exploitation continues to this day18 (source: T.Pao, Arabic and Chinese Trade in Walrus and Narwhal Ivory).