Eastern Fox Squirrel

A solidly black Eastern Fox Squirrel clinging to the reddish fibrous trunk of a tall coastal redwood, photographed from below against a blue sky.

Black squirrel hugging a redwood tree

Eastern Fox Squirrel (Sciurus niger) The largest tree squirrel in North America, Bay Area populations frequently express a striking all-black (melanistic) coat that sets them apart from the rusty-orange form seen elsewhere. San Mateo’s parks and neighborhoods are dense with Eastern Fox Squirrels — a non-native species that spread across the Bay Area after introductions in the early 20th century and now outnumbers native Western Gray Squirrels in many urban areas. ...

A fully melanistic black squirrel perched on a bare branch high in a large tree against a blue sky

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