Botswana investigating deaths of hundreds of elephants

Hundreds of elephants have been found dead in Botswana's Okavango Delta, but the cause of their death remains unknown.

Still photographs show the dead elephants laying on their sides, others on their front, having collapsed face-first to the ground.

Poaching has been ruled out as the carcasses were found intact.

Government figures put the elephant death toll at 275, but National Park Rescue said the number is more than 400.

Co-Founder Mark Hiley calling the deaths "one of the biggest disasters to impact elephants this century."

According to Hiley, the elephants began dying in huge numbers in early May but the government was slow to react.

With no tests completed, there has been no new information regarding the deaths.

Authorities are investigating.

Africa's overall elephant population is declining due to poaching, but Botswana -- home to almost a third of the continent's elephants, has seen numbers grow to 130,000 from 80,000 in the late 1990s, owing to well-managed reserves.