The once sleepy town of Livingstone is now a battleground between elephants and humans competing for habitat, said Dr. Loki Osborn, of the World Conservation Union. The elephants trample crops and have killed four people, including two children, in the last year.

Elephants have rebounded since a ban on ivory sales was imposed in 1989. In Zambia alone, the elephant population has risen from a low of 7,000 to an estimated 30,000 today, The Sunday Times reported.

"People believe elephants are near extinction," Osborn said. "In fact it's the other way round -- they're re-colonizing parts of southern Africa where they haven't been for 100 years.

Gay Bradshaw, a psychologist at Oregon State University, believes the elephants are suffering severe stress from loss of habitat and seeing members of their clan culled to keep elephant populations under control.

"If the infant elephant experiences trauma such as witnessing the death of the mother, the brain is affected," said Osborn, adding elephants are highly social and depend on each other much the way humans do.