Title: The Difference Between A Narwhal and Swordfish - KnowledgeNuts
Headings: The Difference Between A Narwhal and Swordfish
The Difference Between A Narwhal and Swordfish
What is their “spike” made of, anyway?
Fish vs Mammals
Where do they live?

Content: While the narwhal looks like some kind of magical sea unicorn, it turns out that its “horn” is not a horn at all — it’s a tusk! The big, twisted spike you see coming out of the front of a narwhal is really one of its teeth: a canine. This is a very unusual adaptation, to have exactly one tooth longer than the others; we’re used to seeing animals that are more “symmetric”, or the same on the left side and the right side. Still, asymmetric adaptation does happen (just look at the very photogenic fiddler crab .) Zoologists used to think the narwhal’s tusk is used to fight other narwhals, but now we think narwhals may talk to each other by touching tusks, and they can “tap” fish with them to stun them. A narwhal’s tusk grows between 1.5 and 3 meters and will weigh about 10 kilograms. Meanwhile, the swordfish’s “sword” is a long bill — basically, it’s their upper lip! The sword bone grows forward out of the swordfish’s skull and is not only very strong, it’s able to repair itself after breaking.