A cocker spaniel who was born with a rare birthmark has gone viral on social media, and internet users can’t cope with the heartwarming pictures shared by his owner.
In a viral Instagram post shared in January under the username @ralphie_showcocker, the pup, whose fur is entirely brown on one side of his face and body, and pitch black on the other, can be seen napping on the couch, enjoying being spoiled by his parents on his birthday.
“Celebrating 1 year with our puppy love. You’ve brought us so much joy sweet Ralphie,” the caption says.
The poster, Ryan Fordham from the United Kingdom, told Newsweek that Ralph really is a one of a kind, even within his own litter.
“Even his offspring won’t have his colors making him the one and only. His brothers and sisters where either solid gold or black. If he does have a litter they’ll be either solid gold or solid black,” he said.
Fordham said that this striking look is the result of a genetic phenomenon known as somatic mosaicism, which is a mutation occurring in a single body cell during development, that creates patches with a different genotype, often resulting in unique, multi-colored coats.
There are two types of mosaicism, somatic mosaicism, where body cells carry the variation, and germ-line mosaicism, where some reproductive cells are affected and could pass the change to offspring.
This unusual condition doesn’t cause any health problems in dogs. Its physical signs depend on which tissues have the altered cells, so unusual markings don’t always mean mosaicism.
In contrast, chimerism involves two embryos merging early in development, creating an individual with two wholly distinct sets of DNA, which is very rare.
Other coat color abnormalities in dogs, unrelated to mosaicism, include albinism, vitiligo, and aurotrichia.
True albinism causes very light pigment, eye defects, and higher vulnerability to sun‑related skin cancer. Heavy white patterns—such as extreme white spotting, piebald, dominant white, or merle—may occur alongside deafness or neurologic issues in certain breeds.
Vitiligo leads to shifting pale patches on the face without affecting overall health and lacks effective treatment.
Aurotrichia, seen mostly in miniature schnauzers, produces temporary golden streaks along the back, sometimes with mild thinning, and typically returns to normal within a couple of years.
The video quickly went viral on social media and it has so far received over 227,000 likes and 542 comments on the platform.
One user, Nuzuzuspaniels, commented: “His color markings are so beautiful and unique, he is certainly one of a kind.”
Another user, Slindbergimages, added: “Ralph’s is so adorable. Love his colors.”
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