Snakes and spiders in Washtenaw County, Michigan
Washtenaw County, home of Ann Arbor, has 11 snake and 45 spider species on record, from 754 licensed snake and 363 spider records. Venomous species here: the eastern massasauga.
Are there venomous snakes or spiders in Washtenaw County?
Yes. The eastern massasauga: 61 licensed records, 25% of all Michigan records of it.
What snakes are in Washtenaw County?
In all, 11 snake species are on the Washtenaw County list. The most recorded are the common garter snake (265), the Butler's garter snake (103) and the DeKay's brown snake (75). Washtenaw County holds more than half of all Michigan records of the queen snake.
| # | Species | Records | Share of Michigan records |
|---|---|---|---|
| 1 | Common garter snake Thamnophis sirtalis | 265 | 14% |
| 2 | Butler's garter snake Thamnophis butleri | 103 | 36% |
| 3 | DeKay's brown snake Storeria dekayi | 75 | 21% |
| 4 | Eastern massasauga venomous Sistrurus catenatus | 61 | 25% |
| 5 | Eastern milksnake Lampropeltis triangulum | 50 | 18% |
| 6 | Queen snake Regina septemvittata | 42 | 70% |
| 7 | Northern water snake Nerodia sipedon | 37 | 6% |
| 8 | Eastern racer Coluber constrictor | 35 | 23% |
| 9 | Eastern ribbonsnake Thamnophis saurita | 29 | 12% |
| 10 | Red-bellied snake Storeria occipitomaculata | 24 | 6% |
| 11 | Smooth green snake Opheodrys vernalis | 10 | 4% |
When are snakes out in Washtenaw County?
Observation records of snakes in Washtenaw County run mostly March through October, peaking in April with 30% of them; across Michigan the peak is May.
What spiders are in Washtenaw County?
In all, 45 spider species are on the Washtenaw County list. The most recorded are the bold jumper (36), the familiar jumping spider (21) and the orchard orbweaver (21). Washtenaw County holds more than half of all Michigan records of the northern yellow sac spider and Allocosa funerea.
| # | Species | Records | Share of Michigan records |
|---|---|---|---|
| 1 | Bold jumper Phidippus audax | 36 | 24% |
| 2 | Familiar jumping spider Platycryptus undatus | 21 | 14% |
| 3 | Orchard orbweaver Leucauge venusta | 21 | 23% |
| 4 | Dark fishing spider Dolomedes tenebrosus | 19 | 25% |
| 5 | Nursery web spider Pisaurina mira | 17 | 22% |
| 6 | Northern yellow sac spider Cheiracanthium mildei | 15 | 71% |
| 7 | Zebra spider Salticus scenicus | 13 | 14% |
| 8 | Black-and-yellow argiope Argiope aurantia | 12 | 27% |
| 9 | Furrow orbweaver Larinioides cornutus | 12 | 24% |
| 10 | Dimorphic jumper Maevia inclemens | 11 | 20% |
| 11 | Spined micrathena Micrathena gracilis | 11 | 24% |
| 12 | Asian wall jumper Attulus fasciger | 8 | 24% |
| 13 | Triangulate bud spider Steatoda triangulosa | 8 | 20% |
| 14 | Bridge orbweaver Larinioides sclopetarius | 7 | 15% |
| 15 | Bowl and doily spider Frontinella pyramitela | 6 | 38% |
| 16 | Whitebanded crab spider Misumenoides formosipes | 6 | 35% |
| 17 | Brilliant jumping spider Phidippus clarus | 5 | 23% |
| 18 | Flower crab spider Mecaphesa asperata | 5 | 14% |
| 19 | Garden spider Araneus diadematus | 5 | 8% |
| 20 | Spotted orbweaver Neoscona crucifera | 5 | 19% |
| 21 | Flea jumping spider Naphrys pulex | 4 | 11% |
| 22 | Sixspotted orbweaver Araniella displicata | 4 | 11% |
| 23 | Banded garden spider Argiope trifasciata | 3 | 14% |
| 24 | Dock spider Dolomedes scriptus | 3 | 25% |
| 25 | Dysdera crocata | 3 | 33% |
| 26 | Grayish jumping spider Phidippus princeps | 3 | 27% |
| 27 | Longbodied cellar spider Pholcus phalangioides | 3 | 43% |
| 28 | Paraphidippus aurantius | 3 | 30% |
| 29 | Shamrock orbweaver Araneus trifolium | 3 | 21% |
| 30 | Tuftlegged orbweaver Mangora placida | 3 | 17% |
| 31 | Bronze jumper Eris militaris | 2 | 4% |
| 32 | Peppered jumper Pelegrina galathea | 2 | 17% |
| 33 | Wetland giant wolf spider Tigrosa helluo | 2 | 33% |
| 34 | Allocosa funerea | 1 | 50% |
| 35 | American green crab spider Misumessus oblongus | 1 | 11% |
| 36 | Broad-faced sac spider Trachelas tranquillus | 1 | 12% |
| 37 | Garden ghost spider Hibana gracilis | 1 | 14% |
| 38 | Marbled orbweaver Araneus marmoreus | 1 | 6% |
| 39 | Putnam's jumper Phidippus putnami | 1 | 12% |
| 40 | White-jawed jumping spider Hentzia mitrata | 1 | 11% |
| 41 | Arrowhead orbweaver Verrucosa arenata | — | — |
| 42 | Black laceweaver Amaurobius ferox | — | — |
| 43 | Common candy-striped spider Enoplognatha ovata | — | — |
| 44 | Parson spider Herpyllus ecclesiasticus | — | — |
| 45 | Sixspotted fishing spider Dolomedes triton | — | — |
When are spiders out in Washtenaw County?
Observation records of spiders in Washtenaw County run mostly April through October, peaking in August with 19% of them; across Michigan the peak is June.
What stands out in Washtenaw County
Species for which Washtenaw County holds a large share of all Michigan records: the northern yellow sac spider, 71% (15 of 21); the queen snake, 70% (42 of 60); the Butler's garter snake, 36% (103 of 284); the black-and-yellow argiope, 27% (12 of 45); the dark fishing spider, 25% (19 of 76); the eastern massasauga, 25% (61 of 246); the furrow orbweaver, 24% (12 of 50); the spined micrathena, 24% (11 of 46).
Common in Michigan, not on the Washtenaw County list
Among the snakes most recorded across Michigan, these do not reach the county list: the ring-necked snake (180 statewide) and the eastern hog-nosed snake (165 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Among the spiders most recorded across Michigan, these do not reach the county list: the goldenrod crab spider (67 statewide). Few records here can mean the species is rare in the county, or that few people have looked.
Harmless lookalikes in Washtenaw County
No copperheads reach the county list, and GBIF holds no copperhead record for Michigan under any license, so one reported here is most likely a harmless lookalike: the eastern milksnake and the northern water snake. No cottonmouths reach the county list, and GBIF holds no cottonmouth record for Michigan under any license, so one reported here is most likely a harmless lookalike: the northern water snake. No coral snakes reach the county list, and GBIF holds no coral snake record for Michigan under any license, so one reported here is most likely a harmless lookalike: the eastern milksnake. No widow spiders reach the county list, but the northern black widow is on the Michigan list: treat any spider like it as venomous until identified. Harmless species often taken for them here: the triangulate bud spider. Recluse spiders are not on the Michigan list, but GBIF holds 1 recluse spider record of any license in Michigan (brown recluse 1): treat any spider like this as venomous until identified. Harmless species often taken for them here: the longbodied cellar spider.
Washtenaw County among Michigan counties
By licensed snake records Washtenaw County ranks 1st of 83 Michigan counties with any.
Other Michigan counties with their own page: Isabella County.
The whole state: venomous species in Michigan, all snakes, all spiders.
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.