Moscow, Jan 19 (IANS/RIA Novosti): A European bison died in a wildlife reserve near Moscow after an overdose of caffeine and amphetamine, according to a forensic study.

The bison Shponti died Jan 7, and media reports put its death down to poisoning by rotten tomatoes and tangerines.

But an independent examination has found unusually high levels of stimulants in the late bison's kidney.

The dose was enough to cause cardiac arrest in the 1,300-kg animal, said veterinarian Vyacheslav Vasin.

But a deliberate attempt on Shponti's life was unlikely, because amphetamine is very costly, he said.

Shponti likely came across the stimulants by chance, Vasin said but failed to propose a possible scenario of how it happened.

The results of the official forensic inquiry into the death would not be available until mid-February.

Shponti, 15, was a breeding bull imported from Germany. Its mate, female bison Madonna, died on the same day as Shponti, though it remained unclear whether she also overdosed on stimulants.

In October, the wildlife reserve lost another breeding bull, eight-year-old Multon. The animal broke its jaw under unclear circumstances and had to be shot.