Feared to be extinct, a Hill's horseshoe bat (Rhinolophus hilli) has now been found in one of the caves of Rwanda's Nyungwe National Park, a highly biodiverse area containing old-growth cloud forest.

It is the first sighting in 40 years.

The search for the elusive, odd-looking bat was part of a 10-day, 10-night expedition by a team of scientists from several countries.

"When we caught it, we all just looked at it and said, 'You look ridiculous. Look how big your nose leaf is'," Dr Jon Flanders, director of endangered species interventions at Bat Conservation International and an expedition member, told environmental news site Mongabay.

Rhinolophus bats echolocate through the unique and exaggerated folds on their noses called "nose leaves", which, in the case of the Hill's horseshoe bat, give them a bass frequency, unlike the soprano of other horseshoe bats.

Now that researchers have identified their call, they can use acoustic monitoring to eavesdrop on the critically endangered species with minimal impact. The remaining bats are believed to be restricted to a core area of the park.

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