Scientists think they have resolved one of the most controversial environmental issues of the past decade: the curious case of the missing frogs' legs.

Around the world, frogs are found with missing or misshaped limbs, a striking deformity that many researchers believe is caused by chemical pollution.

But tests in the lab shown here suggest the real cause is likely to be dragonfly nymphs, which like to eat the legs of tadpoles.

Video courtesy of Brendan Ballengee.