Animals Pets Why Do Huskies Have Blue Eyes? Husky Eye Color Explained Learn the science of husky eye color, plus why some huskies have heterochromia. By Bryan Nelson Bryan Nelson Twitter Writer SUNY Oswego University of Houston Bryan Nelson is a science writer and award-winning documentary filmmaker with over a decade of experience covering technology, astronomy, medicine, animals, and more. Learn about our editorial process Updated December 14, 2021 Share Twitter Pinterest Email balazscsilla / 500px / Getty Images Animals Wildlife Pets Animal Rights Endangered Species In This Article Expand Genes Explain Husky Eye Color Huskies and Heterochromia Eye Color in Husky Puppies Blue Eyes in Huskies vs. Other Breeds Huskies are a medium-sized, thick-furred sled dog breed largely associated with polar regions. They're as known for their blue eyes as they are for their triangle ears and distinctive, wolflike markings. Though it's one of their most distinguishing and celebrated features, not all huskies have blue eyes. They have just as much chance of being brown-eyed and a smaller chance of having bi-colored eyes (also called heterochromia) or parti-colored (blue mixed with brown) eyes. Very rarely, they can even have green irises. Huskies' eye color boils down to genetics. More specifically, it's a result of a mutation that reduces their eye pigmentation. Learn more about the science behind huskies' characteristic blue eye color. Why This Matters to Treehugger At Treehugger, we are advocates of animal welfare, including our pets and other domestic animals. The better we understand our dogs, the better we can support their wellbeing. We hope our readers will adopt rescue pets instead of shopping from breeders or pet stores, and will also consider supporting local animal shelters. Genes Explain Husky Eye Color Two genetic variants, piebald and merle, are known to underlie blue eye color (and also uncommon coat colors) in most dog breeds, including Dalmatians, border collies, and Shetland sheepdogs. Scientists have long known that these variants do not explain the blue eyes of huskies, which exhibit the phenomenon much more often than other breeds. But they weren't always sure what caused it. It wasn't until 2018 that a study seemed to confirm the source of the icy hue as a duplication on the 18th chromosome. A New England dog DNA startup called Embark Veterinary, Inc., was behind the seminal study, reportedly the first consumer genomics study ever conducted in a non-human model and the largest canine genome-wide association study to date. More than 6,000 dogs partook in the genetic testing. The study found that the duplication occurs near ALX4, a protein coding gene associated with development of the craniofacial and appendicular skeleton. The ALX4 gene hasn't in the past been associated with eye color in human or mice studies, so this was somewhat of a groundbreaking finding. Researchers found the same genetic quirk in non-merle Australian shepherds, which also tend to have blue eyes. Most huskies with this chromosomal abnormality are born with less melanin (pigment) in their irises and, therefore, a lighter eye color. But not all dogs that have the mutation are aqua-eyed, so researchers say there may be more than just a genetic mutation at play. Huskies with and without the mutation can also have brown eyes or a mix of brown and blue. Huskies and Heterochromia TRAVELARIUM / Getty Images When a dog's (or any animal's) eyes are two different colors, it's called heterochromia. The same mutation that causes huskies to have blue eyes is what causes this bi-coloring. It's passed down through the parent's DNA, and because it's a dominant trait, only one copy of the causal variant is enough to result in either blue eyes or heterochromia. The mutation can also appear as parti-colored eyes, in which colors are mixed within one iris. The common combo in huskies is, of course, brown and blue. When this occurs, you're likely to see a blending of hues happening around the edges of the iris. Eye Color in Husky Puppies Elizabeth Fernandez / Getty Images All husky puppies are born with blue eyes. Over time, the puppies develop more melanin pigment in their eyes, which can result in two brown eyes, heterochromia, or parti-coloring. When a dog's eyes change color, it typically happens before 12 weeks, though some can change as late as 16 weeks. After that, a dog's eye color has reached its permanence. Blue Eyes in Huskies vs. Other Breeds Herding dogs like Australian shepherds can also have blue or bi-colored eyes due to the merle variant. Patricia Marroquin / Getty Images A number of dog breeds have blue eyes due to having the piebald or merle variant. Piebald is most often a variant of the MITF gene, which also results in white spots in the coat (usually on the belly and neck). Breeds that could have blue eyes on account of this variant include boxers, American Staffordshire terriers, bull terriers, and Dalmatians. In many cases, piebald dogs with blue eyes are also at least partially deaf, as the MITF gene is associated with hearing. Then, there's the merle variant, which results in a coat pattern of patchy black, silver, brown, beige, and/or white. This commonly affects herding breeds like Australian shepherds and collies but can also occur in great Danes, French bulldogs, dachshunds, and corgis. "Double-merles"—or puppies born with two copies of the merle gene—often face some level of deafness and/or blindness. Thankfully, though, unlike piebald, merle is a recessive gene. Unlike other dog breeds, huskies (and non-merle Australian shepherds) aren't known to experience any hindering genetic defects due to the mutation that causes their blue eye color. Dog owners should be aware, however, that blue eyes in general are naturally more sun sensitive. The genetic duplication is also not associated with coat color, as is the case with the piebald and merle variants. Huskies can have blue eyes whether they're brown, black, or grey. View Article Sources Strain, George M. "The Genetics of Deafness in Domestic Animals." Frontiers in Veterinary Science. 2015. Deane-Coe, Petra E., Erin T. Chu, Andrea Slavney, Adam R. Boyko, and Aaron J. Sams. "Direct-to-consumer DNA testing of 6,000 dogs reveals 98.6-kb duplication associated with blue eyes and heterochromia in Siberian Huskies." PLOS Genetics. 2018. "When do puppies' eye color change?" National Canine Research Association of America. 2021. Stritzel, S., A. Wöhlke, and O. Distl. "A role of the microphthalmia-associated transcription factor in congenital sensorineural deafness and eye pigmentation in Dalmatian dogs." Journal of Animal Breeding and Genetics. 2009. Savel, Sophie, and Patty Sombé. "Are dogs with congenital hearing and/or vision impairments so different from sensory normal dogs? A survey of demographics, morphology, health, behaviour, communication, and activities." PLOS One. 2020.