Why do animals prick up their ears?

Answer 1

They are pointing them toward a sound to hear better.

Answer 2

Pricking of the ears is a sign that an animal is suddenly alert to a specific sound it hears that is regarded as unfamiliar or something that is not usually heard in its regular routine. Or it could be that they hear something familiar that either means something pleasant is about to happen, like when a human calls out to some horses or cows when feeding time is about to happen, or something bad and needs to be avoided or chased away occurs, like horses spooking at the sound of the wind, or a cow or bull chasing after a coyote that comes into that cow or bull's territory.
it's a sign of interest and alertness
that way they can hear better

to direct their ears (using fine ear muscles, vaguely remnant in humans, especially those that can wiggle their ears!) towards the sound!

Try cupping your hands to your ears to see how much better you can hear in different directions as you change the angle of your hands. You may look a bit like an elephant doing this though!)

Answer 3

Animals prick up their ears to better hear sounds around them. This allows them to detect potential threats, communicate with others, and locate prey or food sources. By directing their ears towards the source of a sound, animals can accurately assess their environment and respond accordingly.