“OMG! Come hear boy! I deafinitely need you in my life!”
Everyone has seen that dog at the park with the gorgeous milky white coat and the most striking blue eyes. You can’t deny their beauty, but you may have noticed that the dog may also be deaf.
What is deafness?
Deafness is a loss of hearing, and occurs when sound is unable to reach the brain. During the normal process of hearing, sound waves enter the ear through the canal where they reach the middle-ear eardrum. The eardrum acts like a gong causing vibrations that activate vibrate three little bones. These bones shake with the vibrations, passing them into the inner ear. The inner ear is filled with fluid and tiny hairs, this fluid ripples from the vibrations, bending and moving the hairs. The movement of these hairs are attached to nerves that lead to the brain. These nerves turn the movement of hair into electrical signals the brain can understand. AND PRESTO… we can interpret sound!
So why are white dogs deaf?
Not all white dogs will be deaf, but a majority of deaf dogs will be white (or mostly white). In fact, around 85 dog breeds have been linked with inherited deafness.
White dogs are often affected by deafness due to the coat marking genes, merle and piebald. Merle and piebald are markings that affect the amount of pigment that’s present. Pigment is what normally gives dogs there colour, black/brown hair, green/brown eyes etc. So a dog with little or no pigment will be white, and if it also affects the eyes, the irises will be blue.
The cells responsible for producing pigment are also found in the ear, and this is where a lack of pigment can cause deafness in dogs.
Merle and Piebald: why breed them?
The merle gene can be seen on dogs such as dappling on dachshunds and as the harlequin marking on Great Danes. Trouble starts when two dogs with the merle gene are bred together. The colour of the merle or the breed of the dog does not matter.
Merle is what is known as a dominant gene. Dogs only need one merle gene for it to show up on their coat. A dog with two merle genes gets too much of the coat pattern. This causes less pigment to show up, leading to dogs that are mostly or all white.
Two merle dogs have a 25% chance of producing a double merle puppy, and a 50% chance of producing a regular (one) merle puppy. It is the double merle pups that are prone to pigmentation issues and deafness.
In order to get a regular healthy dog with the merle coat pattern, one merle dog must be bred with another dog that does not have the merle pattern. This leads to 0% chance of a double merle and a 50% chance of regular (one) merle puppy.
So there really is absolutely no need for 2 merle dogs to be bred together.
The piebald marking is a lot more complex to explain but still leads to dogs having little to no pigment resulting in dogs with too much white.
How do you know if your white puppy is deaf?
Vets can perform a BAER (Brainstem Auditory Evoked Response) test. Headphones or specialised earbuds are placed in the dogs ears and a series of noises (usually clicks) are played into each ear. Little probes are placed in around the dog’s ears and neck and can pick up on any electrical signals the ears are relaying to the brain. The electrical signals show up as waves on a screen, a normal hearing dog will produce large waves, while a deaf dog will show little to no waves at all. Deafness can occur in one or both ears and the BAER test can determine the difference in hearing in both ears.
So should I avoid buying a white puppy?
Not necessarily, deaf dogs still make wonderful pets. Dogs are intelligent and can quite easily pick up on hand signals instead of vocal commands, but they do take a bit of extra care to keep them safe (they can’t hear cars or see your hand signals if they aren’t facing you!).
So while bright blue eyes and stark white coats can make a puppy irresistible, do your research. Is the breed prone to deafness? Do they carry the merle or piebald gene? And be prepared to work that little bit harder if the puppy ends up being deaf.
Great website with helpful links to resources and connect with other deaf dog owners!