Animal that has generally no natural predators, why?

The African Bush Elephant is the largest living terrestrial (land) animal, with males reaching 6 to 7.5 metres (19.7 to 24.6 ft) in length, 3.3 metres (10.8 ft) in height at the shoulder, and
weighing 6 t (13,000 lb).

Females are much smaller, reaching 5.4 to 6.9 metres (17.7 to 22.6 ft) in length, 2.7 metres (8.9 ft) in height at the shoulder, and weighing 3 t (6,600 lb). The adult African bush elephant generally has no natural predators due to its great size, but the calves (especially the newborn) are vulnerable to lion and crocodile attacks, and (rarely) to leopard and hyena attacks