Lead scientist Anders Moller of the University of Paris-Sud said his team compared animal populations in radioactive areas around the disabled nuclear power plant with those in less contaminated areas.

"What we found was the same basic pattern throughout these areas — the numbers of organisms declined with increasing contamination," Moller wrote in the journal Biology Letters.

He and colleague Timothy Mousseau had earlier found that brightly colored birds were also some of the hardest hit animals after the Chernobyl plant exploded in 1986.

Many animals in the area of highest contamination have been observed to have deformities.

"Usually [deformed] animals get eaten quickly, as it's hard to escape if your wings are not the same length," Moller said.

Some Ukraine researchers have challenged findings by Moller and his colleagues.

Sergii Gashchak, of the Chernobyl Center, told the BBC he drew “opposite conclusions” from the same data Moller's team collected on birds. "Wildlife really thrives in Chernobyl area — due to the low level of [human] influence," he said.

Gashchak asserts that “life appeared and developed under the influence of radiation, so mechanisms and resistance of recovery evolved to survive in those conditions.”

Ukrainian officials have turned the area around the nuclear disaster into what they call a nature reserve, inhabited by wolves, bison and bears.

Photo: Chernobyl.info