Explained: How ‘Hulk’ the German-Shephard puppy got his lime-green colour

Before this in 2017, Rio a golden retriever in the Scottish Highlands gave birth to nine puppies, one of which was green. News reports from that time suggest that the colour of the puppy came from the bile pigment biliverdin as well. This puppy was named Forest.

A lime-green puppy?

There is nothing wrong with the puppy, whose fur was probably stained by a fluid present in his mother’s birth sac. Hulk’s lime-green tint has already started to become lighter. On Thursday, Asheville based daily newspaper Citizen Times reported that regular baths and daily licks from his mother Gypsy are expected to fade Hulk’s green hue in a few weeks. “By Jan. 16, Hulk is starting to look more like an Easter peep than his namesake hero,” the report said.

Bile pigment, meconium or uteroverdine?

It is not clear. Various news reports suggest that Hulk’s green colour can be attributed to meconium, which is a puppy’s first stool. But in her book titled, “Canine Reproduction and Whelping: A Dog Breeder’s Guide”, dog breeder Myra Savant-Harris writes that while in humans meconium is a sign of fetal distress, it is not the case with dogs. She writes that a portion of the canine placenta contains a green pigment called uteroverdine. Harris has attributed some newborn puppies’ green colour to this pigment. “It is not a bad sign. It is not a sign of fetal distress. It is normal for the colour green to appear in the amniotic fluid of the puppy.”

“If a placenta has been held back in the body of the bitch, the uteroverdine may even discolor a subsequent puppy slightly and the body of the puppy may be slightly green. This is not abnormal, she writes.”

Human placentas do not have this green pigment. In a separate post, Harris writes that canine meconium is mustard-yellow in colour and puppies that are born alive with this colour surrounding them should be “watched carefully for the first few days of their lives in case they have aspirated the meconium.”

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