Not usually. It depends on the breed, though. Because most small dogs have flappy ears, their hearing is generally impaired compared to their pointy eared cusins. Dogs whos ears sort of go up then flop, as well as get pulled back against the head ((like a gray hound)) usually have the best hearing. Dog's with pointy ears that stick straight up are second in line, and dogs who have floppy ears are usually deaf compared to other breeds.
their ears their ears their ears
Gerbils are desert burrowing animals, so I would think (I am not a biologist) that they have small ears to help reduce sand getting in their ears. They originated in Mongolia, which is between China and Russia (the old Soviet Union for those of us who are older), so it is colder there, so smaller ears would reduce heat loss as well. They are desert animals, but not all deserts are cold. :)
Usually yes, because larger outer ears collect and enhance vibration better. But this is not the only criteria for excellent hearing -- the sensitivity of the eardrum and inner ear is also important. Some animals can hear sounds better than any human.
Animals may have smaller ears because they live in cold environments and heat is lost through your ears
Cats, dogs, rabbits...
polar bears aren't small you imbecile
Look at the rabbit and ask yourself the same question -.-'
The shape of an animal's ears can help determine how well it can hear. Large ears tend to collect and funnel more sound waves to the ear canal, improving hearing sensitivity. The distinctive shapes of some animals' ears can also help them detect the direction of a sound more accurately.
Elephant
Polar bears have small ears so they do not lose much heat from their bodies. Like your head and feet, heat can be lost through our ears. Their smaller ears help them keep all the heat they can get in their chilly arctic environments.
So they can hear better... since they're small
animals can have holes for ears or can use smell if they don't have ears