Question

great gray owls, known for their large facial discs, have evolved remarkable adaptations to detect voles hidden beneath snow cover. according to a study by clark et al. at uc riverside, the owls facial disc functions as an acoustic radar, capable of picking up low - frequency sounds emitted by burrowing voles through as much as two feet of snow. however, since snow refracts sound, the owl may perceive an acoustic mirage from certain angles, where the voles acoustic position is offset from its actual location. to counter this distortion, the owls spend a moment hovering directly overhead - the listening position with the least refraction - before plunging straight down to strike their prey.
according to the text, how does the great gray owl overcome a perceived acoustic mirage when hunting a vole burrowing beneath snow cover?
choose 1 answer:
a it uses its large facial disc as an acoustic radar to detect the voles burrowing sounds.
b it attacks from a great distance to avoid the sound distortion.
c it hovers directly above the source of the sounds to confirm the voles location.
d it hunts voles only when the snow cover is less than a foot deep.

Explanation:

The text states that the great gray owl hovers directly overhead (the position with the least refraction) to counter the "acoustic mirage" caused by snow refracting sound. This helps the owl confirm the vole's location. Option A describes the function of the facial disc (detecting sounds), not overcoming the acoustic mirage. Option B is incorrect as the text doesn't mention attacking from a great distance. Option D is not supported by the text which mentions the owl can detect sounds through two - feet of snow.

Answer:

C. It hovers directly above the source of the sounds to confirm the vole's location.