Until humans arrived in New Zealand, only two mammals had taken up residence on the islands; the short and long tailed bats. Without predators to threaten them, hunting for food on the ground was relatively safe, so the short tailed bat developed a taste for ground dwelling arthropods. But how the resourceful bat locates buried morsels wasn't clear. The bat couldn't be using echolocation; it must be doing something else. Gareth Jones and his colleagues began analysing the mammals hunting strategy, on both the wing and ground, and discovered that although echolocation is still the bat's method of choice for trapping airborne prey, the bat tuned its acute hearing to listen out for terrestrial snacks when hunting on the ground (p. 4209).
Working with Peter Webb, Jane Sedgeley and Colin O'Donnell, Jones began recording the bat's hunting calls in their cluttered native forests and in the lab, to see how they used echolocation while hunting on the wing. But next the team wanted to see how the bats located buried fodder.
Hiding live and dead mealworms under leaf litter, the team were astonished at the speed that the bats located the live offerings. Jones says that `On the ground, [the] bats moved rapidly and adeptly... digging in the leaf litter... sometimes disappearing completely'. The bats had found the live mealworms too quickly to be relying on their sense of smell; the team realised that they must be using their ears to home in on the mealworms' rustling.