(Inside Science) — When do you need a broadsword, and when would you be better off with a dagger? That’s the question that faced artiodactyls, the group of mammals that includes deer, antelope, goats, giraffes, pigs, buffalo and cows, during their evolution.
Many male artiodactyls fight over females using weaponized body parts such as horns and antlers. But pigs and several groups of deerlike animals have tusks instead, and a few species have both. Water deer have tusks so pronounced they are nicknamed “vampire deer.” To understand this variation, researchers compared the habitats and behavior of 63 species, including members of every living artiodactyl group except hippos and whales. They also measured the canine teeth of each species using skeletal specimens in museums.
The species in which males’ canines were enlarged into tusks were much more likely to be small-bodied and to live solitary lifestyles. And while no direct statistical ...
