Aida Vallelado Molina of Laguna de Duero, Spain, has delivered many litters of hunting dogs, but none with such shocking results: On June 3, her dog had a litter of five puppies, two of which were the color green.
"I couldn't believe it when I first saw them,” Molina told The Local. “I thought the puppies were dirty and tried to clean them, but the color wouldn't come off.”
Though the green dogs have been dubbed the “Hulk pups” by several media outlets, they don’t share the superhero’s strength. The green female died shortly after birth; the green male survived, but is very weak.
The odd coloration and the death of the female pup are being investigated by local veterinarian Dr. Daniel Valverde (which some may consider ironic given that “verde” is Spanish for “green”).
“There are no other recorded cases of this happening in Spanish scientific literature," Valverde told Laguna al Día.
He is conducting several tests to find definitive answers. However, while rare, puppies born with green pigmentation are not unheard of. In 2012 a green Labrador retriever was born in England. Likewise in 2008 a green golden retriever was whelped in New Orleans. In those cases, the condition was attributed to exposure to biliverdin, a substance produced in the placenta that sometimes comes into contact with amniotic fluids—in essence, the puppies were dyed green in the womb. Both pups’ green coloration faded soon after birth, and the green Spanish hunting dog has also begun to assume normal pigmentation.