But very little is known about their polar opposites on the color spectrum: the black buffalo.

Pat Jamieson, the outdoor recreation planner for the National Bison Range Wildlife Refuge in Moiese, Montana, said that is most likely due to the fact that black buffaloes are even rarer than their albino-looking counterparts.

And Eva Fearn of the Wildlife Conservation Society Institute at the Bronx Zoo explained that black buffalo are so unusual that there are no tangible statistics that document their birth rate. Referencing the “Guide to North American Mammals,” which includes detailed descriptions of more than 400 native species, Ms. Fearn said, “there is no mention at all of buffalo born black.”

So, it is easy to imagine Edwin Tuccio’s surprise when, a few weeks ago, he discovered that two black bison were born on his 250-acre North Quarter Farm in Riverhead.