Synaptomys borealis ()
Mass: 21.3 g based on Smith and Foster 1957
Latitudinal range: 36.3° to 58.8°Habitats: boreal forest/taiga (1)
onlyFound in 6 samples
Canada: Churchill (1952)
United States: Bat Cave (Late Pleistocene), Robinson Cave (Late Pleistocene), Bootlegger Sink (Pleistocene - Holocene), New Paris Sinkhole No. 4 (Late Pleistocene), Natural Chimneys (Late Pleistocene)
Size measurements:
| body mass | 21.3 g | N = 10 | Smith and Foster 1957 |
| hind foot length | 19 mm | N = 10 | Smith and Foster 1957 |
| hind foot length | 19 mm | N = 1 | Quay 1955 |
| hind foot length | 20 mm | N = 1 | Quay 1955 |
| hind foot length | 20 mm | N = 1 | Quay 1955 |
| tail length | 23 mm | N = 10 | Smith and Foster 1957 |
| tail length | 22 mm | N = 1 | Quay 1955 |
| tail length | 23 mm | N = 1 | Quay 1955 |
| tail length | 24 mm | N = 1 | Quay 1955 |
| total body length | 118 mm | N = 10 | Smith and Foster 1957 |
| total body length | 127 mm | N = 1 | Quay 1955 |
| total body length | 117 mm | N = 1 | Quay 1955 |
| total body length | 115 mm | N = 1 | Quay 1955 |
See also Synaptomys, Synaptomys australis, Synaptomys cooperi, Synaptomys sp.