I took a picture of this dog because I found he had such beautiful colouring.  It wasn’t until I got home and loaded the picture into my computer that I realized he had one blue eye and one brown.  This condition is known as Heterochromia iridis.

Melanin is the substance that gives our skin colour.  In dogs (and people) with eyes that are a two different colours, there is an excess or deficiency of melanin mostly due to genetics, though it may develop over time.  The dogs breeds that are most likely to have one blue eye are Australian sheepdogs, Siberian huskies, American foxhounds, Alaskan malamutes and shih tzus.

Heterochromia iridis is not exclusive to dogs and can be seen in other animals and even people.  Jane Seymour, Mila Kunis, Keifer Sutherland, Demi Moore, and Alice Eve all have this condition. David Bowie’s eyes were of two colours but it was due to an injury.