You see an elephant. You see a walrus. Both are massive, both are social, and both boast a pair of intimidating, continuously growing tusks. It’s easy to look at them and assume they’re distant cousins on the mammalian family tree. You’d be dead wrong.
Assuming two animals are related just because they share a prominent feature is the biological equivalent of assuming everyone named John is part of the same family.
To understand why these two tusked giants are evolutionary strangers, you have to look past the skin and straight into their skulls. When you examine an elephant’s head, the origin of its tusks is glaringly obvious. They jut forward from the premaxillary bone—the exact anatomical spot where mammalian incisors belong. The elephant is, anatomically speaking, just a giant buck-toothed creature with a really long nose.
The walrus, however, is playing an entirely different anatomical game. If you look at a walrus skull, you’ll notice something deeply unsettling: there are no front teeth in the middle of its mouth. The massive tusks aren’t in the front; they are pushed way off to the sides, spanning a width almost as long as the entire row of cheek teeth.
This breaks the rules. Mammals have a single row of teeth. If a walrus naturally grew two separate rows of tusks, biologists would be interrogating its ancestry for generations. The only logical explanation is that these massive teeth were squeezed out of the standard single row.
But which teeth were squeezed out? Not the incisors. The walrus’s tusks sit firmly in the maxilla, meaning they are actually modified canines. While the elephant’s tusks are overgrown front teeth, the walrus’s tusks are overgrown fangs. They aren’t the same teeth at all.
Nature doesn’t care about your naming conventions; it only cares about what gets the food in the mouth.
The reason for this anatomical divergence comes down to diet. Elephants evolved in Africa to eat grass. Walrus evolution was driven by a completely different menu: clams. Try cracking open a shell with your front teeth. It’s awkward, and your incisors just get in the way of stuffing the shellfish into your mouth. So, the walrus simply ditched most of its incisors, keeping only a specialized crushing tooth, and sent its upper canines on a solo mission to become underwater pickaxes.
This is the beauty of convergent evolution. The elephant and the walrus don’t share a recent common ancestor—one is from the Afrotheria clade, the other is a carnivoran from the Laurasiatheria clade. Yet, both needed a tool that resisted wear, so both evolved continuously growing tusks. Both needed immense chewing power, so both developed sagittal crests on their skulls to anchor massive jaw muscles.
Evolution is a relentless tinkerer, not a perfectionist. It uses whatever junk is in the garage to build the machine it needs today.
If you still need proof that these two animals are in no way related, look down. Elephants possess a highly flexible, prehensile ‘fifth leg’ that they can use to scratch their own bellies. Walruses, on the other hand, possess a baculum—a literal penis bone that can reach up to 60 centimeters. You could pick one up and swing it like a baseball bat.
When the elephant and the walrus meet in the evolutionary void, they don’t share a family tree. They just share a really weird set of biological coincidences, and a punchline that proves nature has a dark sense of humor.
FAQ
Q: If they aren't related, why do both their tusks grow continuously?
A: Because both animals use their tusks heavily for digging and foraging, causing constant wear. Continuously growing teeth (seen in rodents, elephants, and walruses) is a functional adaptation to prevent the teeth from grinding away to nothing. It evolved independently in both lineages.
Q: What does the walrus's weird tooth arrangement mean for its survival?
A: It means the walrus is perfectly optimized for its niche. By losing its incisors and moving its canines out of the way, it created a flawless clam-crushing machine. The tusks act as mud-digging pickaxes while the specialized rear teeth act as a shellfish can-opener.
Q: Does this mean we should stop grouping animals by shared physical traits?
A: Yes and no. Shared physical traits are a starting point, but without anatomical and genetic backing, they can be wildly misleading. Convergent evolution proves that similar environments can force completely unrelated animals to look and function almost identically.