Tuskless Elephants

We often think that evolution takes thousands of years. But in rare cases where humans impact small populations, adaptation can work much faster. Take the case of the tuskless elephant. Nearly all male elephants and most females have tusks. These are just elongated lateral incisors that grow outward once the elephant loses its baby teeth. But a small percentage of elephants are born without these teeth and never develop tusks. In 1919, the South African government brought trophy hunters to the East Cape to exterminate elephants that were eating crops and trampling farms. By 1931, only eight females survived, and half were tuskless—perhaps because they made the least attractive trophies. Instead of natural selection, this was human selection. Fortunately, public opinion forced a change of heart and a preserve was established to protect the elephants. The tuskless matriarchs had tuskless offspring, and today nearly all female elephants in the park lack tusks. A similar thing happened in Mozambique. During a 15-year civil war, soldiers poached elephants for their meat to feed the troops and for their ivory to sell to buy more weapons. Again, elephants with tusks were killed, and by the end of the war, half the females were tuskless. As the population has rebounded, a large portion of females remain without tusks. But with the hunting pressure off, experts think natural selection may again favor animals with tusks—and both groups may eventually become tusked again.