Why do only mammals have tusks? Study traces their surprising origins

Tusks are a striking feature of many animals -- elephants, hippos, warthogs, walruses -- and are often sought-after by humans. https://ift...

Tusks are a striking feature of many animals -- elephants, hippos, warthogs, walruses -- and are often sought-after by humans.

https://ift.tt/eA8V8J