Sensor Narwhals may have the strangest teeth of all. Or tooth, I should say. T at thing sticking out of the top of its head? It’s not a unicorn horn. It’s a tooth. T at’s right. It’s a 2.4-meter long, twisted tusk growing through its upper lip. And if you think that’s weird, just wait until
you hear this: Scientists think the narwhal uses its tooth to “taste” the water. A narwhal’s tooth isn’t coated with enamel
like most teeth. T e tooth is porous. Seawater can pass right through it. Inside the tooth are millions of nerve endings that connect to a central nerve which goes to the brain. T ese nerves help the narwhal sense the salt content and temperature of the surrounding water.
Ornament? T e purpose of some animal teeth baffles scientists. Take the sulawesi babirusa, for example. Never heard of it? T at’s okay. It’s a wild pig that lives in Indonesia. Like many pigs, the male babirusa’s canine teeth continue to grow throughout its life. T e lower canine teeth are long and overlap the edge of its snout as they grow. But the upper canines grow up and into the top of the snout. T ey break through the skin and curve back towards the animal’s forehead. T e tusks can reach lengths of 43 centimeters. But what are those tusks for? It’s a mystery.
T e tusks are brittle and easily broken. So the animals don’t use them for fighting. Nor do they use them to root around for food. It may be that the tusks are for display only, to attract females. But no one really knows for sure. One thing is clear: many animal teeth are made for more than just chomping!
Ornament
WORDWISE canine: a pointed tooth
enamel: the hard surface on a tooth
fang: the tooth of a snake, through which venom is injected
incisor: a type of tooth in the front of the mouth for cutting
molar: a wide, fl at tooth used for grinding and chewing
tusk: a long, curved tooth that sticks out of the mouth
ADVENTURER VENTURER 7
Sensor
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