Updated

A 14-year study of nearly 1,000 elephants in Kenya shows an alarming death rate among older, big-tusked males, and an acceleration in poaching deaths toward the end of the study.

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

Targeted poaching deaths of Africa's elephants have accelerated in the last several years. The killings are driven by the rising price of ivory as demand increases across Asia — and especially in China.