Ear location can be different for different species. Majority have ears on their heads, and some don't have ears but have sensors that function like ears. Let's find out then were are some ears located.
Birds have ears located on the side of their head behind the cheek patch. They lack the external part of the ear. It does not resembles animal like ear at all, as a matter of fact it looks like a small slit or a hole beneath the feathers. Fish same like birds, do not have external ears. The ears of the fish are located inside skull with no real connection to the outside. Spiders and crickets have their sensory capability on their legs. Moths have something equivalent to the eardrum and mounted in the middle of their thorax. Snakes in fact do not have ears. To survive they rely on vibrations, heat, and motion.
Lastly let me present you with fascinating fact and unique characteristic of the Leopard Gecko's ears. Their ears go right through their head. Check it out for yourself, just shine a light through their ears.