@jonsblond That happens with a lot of decapods. Here’s a cool image showing a few morphs, my favorite, the rarest of them all, is the orange/black split.
While blue lobsters are rare, they’re not THAT rare and are encountered about 1 in every 2 million.
”“Blue, in particular, is a genetic defect in that the lobsters are producing more of a certain protein than normal,” Bradley said.
“Combined with their normal pigmentation, it forms a blue color. ....The more orange-y ones [when they’re alive] are an expression of the lack of that protein…..”
The only lobsters that don’t turn red in the pot are albinos, sometimes referred to as “crystal” lobsters.
Just as lobsters aren’t all the same color, neither are they necessarily only one color. “Calico” lobsters, as they’ve been called, display mottled shells, usually comprising black and orange. The odds of a calico lobster is 1 in 30 million.
Farther down the statistical rabbit hole, at 1 in 50 million, are split-colored lobsters, or those showing two colors that are distinctly separated—sometimes split down the middle, sometimes showing a more checkerboard pattern. All split-colored specimens observed by the Lobster Institute so far have also proven hermaphroditic.”
http://newswatch.nationalgeographic.com/2012/07/10/weird-wild-odd-colored-lobsters-decoded/