What eats an elephant?
asides from illness, the only animal capable of killing an elephant is a pride of lions. Generally they go after calves, but on the BBC planet earth series I believe, a huge pride did a night time attack on a quite large elephant. An elephants eyesight at night is poor, so the lions used this as an advantage to break up the heard of elephants, and took down the one they targeted with was a juvenile. I doubt a Hyena will be able to, they got powerful jaws, but lack the physical body strength to complete such a task. Also the lions pile on the Elephants back to pull it down, a Hyena doesn’t weigh enough to do this.