A relatively rare and poorly known species, in part because of challenges with identification.
Identification: Very similar to Half-black.
Half-black Bumble Bee (Bombus vagans): Nearly identical and much more common. The best way to distinguish Sanderson’s and Half-black is the shape of the malar space (cheek). In Sanderson’s, the width is usually slightly less than length, whereas in Half-black, the length is a tad longer than the width. Sanderson’s tends to have more black on between the wings and queens regularly have white hairs on T5 and T6 (though apparently other species can occasionally show this).
Global Status: Secure (G5)
Vermont Status: Apparently Secure (S4)
For more information, visit the following links:
Living Atlas Species Page
To see the global distribution, check out the iNaturalist account, and toggle the GBIF layer on the map.