Tiger attacking elephant calves
I agree that given a chance the tiger hunts elephant calves. I have seen tigers stalking and if the elephant calf strays too far then immediately the tiger attacks. At times, the tiger is spotted much before. In one of those instances I have seen the tiger growling a lot to frighten the elephant herd and a lot of roaring and trumpeting followed. Normally when they detect a tiger, immediately the mother takes her calf to the middle of the herd. The idea of roaring is to frighten the herd especially the mother into committing mistakes. I have seen the expression on the face of a person who was with me in one of those instances, and can imagine the impact of those roars on the elephants in general and the mother in particular.
Cheers,
Sabyasachi