A giant bat with a wingspan up to 5.5 feet has made a comeback from the brink of extinction in Tanzania in a rare conservation success, an environmental group said on Friday.

Numbers of the Pemba flying fox, a type of fruit bat, have risen to 22,000 since it was rated critically endangered two decades ago when "only a scant few individual fruit bats could be observed," British-based Fauna and Flora International said.

In a release coinciding with Halloween, it said that the bat's maximum wingspan was "greater than the height of the average British woman."

A conservation drive helped the species recover, an exception to mounting losses of animals and plant species caused by destruction of habitats linked to rising human populations.

The bats were once considered a delicacy and were hunted and eaten throughout Pemba island, the bats' only habitat, in the Zanzibar archipelago off Tanzania.