JOHANNESBURG — A 14-year study of nearly 1,000 ­elephants in Kenya shows an alarming death rate among older males — those with large, valuable tusks — and an acceleration in poaching deaths, the group Save The ­Elephants said Thursday.

The study said that in 2000 the region of Samburu had 38 known elephant males over 30 years of age. But in 2011 only five of those original 38 were still alive. Almost half of the known females over 30 years also died during this period, at least half from illegal killings.