Black squirrel in a tree
Eastern Fox Squirrel (Sciurus niger) North America’s largest tree squirrel, the fox squirrel carries a recessive melanistic gene that occasionally produces all-black individuals with no brown or gray at all. San Mateo’s parks host one of California’s densest populations of melanistic fox squirrels, where all-black coats are so common they’re practically the local standard. Wikipedia | iNaturalist | Observations map