A dog's ear has three major parts, an inner, middle and outer ear. The outer ear is the ear flap, also known as the pinna. This pinna is shaped differently according to the breed of dog. The pinna funnels sound into the ear canal. The ear canal is long and almost makes a right angle as it funnels into the ear. The middle ear has a tympanic membrane or ear drum. It is fragile and can be damaged by disease or cleaning. The middle ear has three small bones, an air cavity called the bulla and an eustachian tube. The inner ear contains nerves for hearing and the centre for balance.
Dogs have tiny hairs in their ear canals.These help them detect changes in position that may help them to hear sounds better. This is why a dog cocks its head to one side occasionally in order to hear a sound better or more clearly. Dogs can hear from 40 Hz to 60,000 Hz in range. This is similar to humans in the lower range but much higher at the high end. Dogs can hear high-pitched whistles and small animal prey. Dogs can also distinguish between sounds that seem identical to a human, such as hearing the difference in a family member's footsteps as opposed to those of a stranger. Dogs' ears can move independently from each other, which gives them greater capability to determine direction and cause of sound.
A dog's outer ear flap is usually covered in fur. Scratching can lead to hair loss or tears in the ear flaps. Watch to see that the ear flap doesn't get swollen, warm or seem painful to the dog when touched. The inner ear skin should be a healthy pale pink in colour. A small amount of discharge, usually dark, is normal but an ear infection may be indicated if the ear is red, there is discharge or a bad smell, or if the dog rubs or scratches their ears or shakes their head frequently. Ears should be cleaned weekly, especially dogs with big floppy ears. Ear cleaner is available at pet supply stores, and the ears should be cleaned with cotton balls and swabs on the outter flaps only. Never put anything in the ear canal or damage can occur.