Last week I learned that a local retired lobsterman named Frank gifted Northeastern’s Marine Science Center a calico lobster. Similar to the particolored cat you’re probably more familiar with, calico lobsters don a mottled pattern of orange, black, and green spots on their shells.
Frank’s buddy had apparently caught the lobster and was set to sell it at a wholesaler in Revere. Frank wouldn’t hear of this, so he called the MSC to see if they were interested in housing it. “I said yes, of course,” said Carole McCauley, the center’s outreach program coordinator.
While calico lobsters are apparently extremely rare — about one in 30 million lobsters is a calico — they seem to get their fare share of media coverage. Back in 2012, another calico was saved from the Summer Shack boiling pots by chef Jasper White, who named the beauty “Calvin” and deemed him too impressive to eat. Calvin’s story made it all the way to the New York Times after finding a permanent home at the New England Aquarium.
Just yesterday, another rare catch from a couple of Maine lobstermen made headlines with their calico creature. But the one thing I’m having trouble finding in any of this media flurry is exactly what makes a calico calico. We asked our resident lobster expert Joe Ayers who said, “I don’t think that anyone knows what causes calico pigmentation.” And based on my own quick literature search, I’m willing to believe him for now.
He did say that calicos are likely mosaics, meaning they contain different cells that have different pigment genes. But there also a dietary role when it comes to lobster pigmentation. A pigment molecule called astaxanthin can either be bound to protein or unbound in the body, according to some research from the NE Aquarium from 2004. If astaxanthin is bound, the lobster appears blue; if it’s unbound, it appears red. Feeding lobsters varying levels of astaxanthin led to varying levels of its bound and unbound form, which the researchers said suggests different mechanisms of uptake. A diet containing very little of the molecule renders the lobster white, a phenotype that’s even rarer than calico in the wild — genetically albino lobsters are one in 100 million, according to the Lobster Institute at the University of Maine. The team of NEA researchers also said that the thickness of the lobster’s shell likely had something to do with their ultimate coloring.
Another rare lobster has one color on one half of its body and another on the other half. Apparently this is made further bizarre by the fact that it is almost always coupled with a phenotype of heterogynadromorphism, which is a really convoluted way of saying hermaphrodite: lobsters with half-and-half coloring also sport half-and-half sex organs.
So, this really leaves us no further along than where we were to begin with. We still don’t know for sure what makes a calico calico. We do know that the trait is extremely rare and extremely cool to look at. I will keep my eyes and ears pealed for more deets on lobster pigmentation, and please, if you know something I don’t, fill us all in in the comments!