If current trends continue, elephants, giraffes, and zebras could go extinct in the not-too-distant future.

Rodents teeming with parasites that carry black plague would fill the void, suggests ongoing research in Africa. If so, the threat to human health could prompt the tantalizingly feasible solution of de-extinction — that is, resurrecting the big animals and releasing them back into the wild.

De-extinction for conservation purposes is a “matter of when, not if,” said Philip Seddon, a zoologist at the University of Otaga in New Zealand. “We need to think very hard about which are the good candidate species.”