Venomous snakes and spiders in Michigan

The only venomous snake on the Michigan list is the eastern massasauga, with 246 licensed records, 5% of all snake records in the state.

One widow species (Northern black widow: 4 records) is on the Michigan list. There is no recluse spider on the Michigan list: no recluse species reaches 10 records in the state. Widow bites cause muscle pain and cramps; recluse bites can cause a slow-healing wound. Both are rare and seldom fatal.

These eight account for 82% of all licensed snake records in Michigan; the most recorded, the common garter snake, alone for 35%.

These eight account for 33% of all licensed spider records in Michigan; the most recorded, the familiar jumping spider, alone for 6%.

Observation records of snakes in Michigan run mostly April through October, peaking in May with 21% of them. December through February together hold under 2% of the records, so snakes in Michigan are rarely recorded in winter. Venomous snakes alone have 19 observation records with a month in Michigan, too few for a season of their own.

Observation records of spiders in Michigan run mostly April through October, peaking in June with 20% of them. Winter (December to February) holds 3% of the records.

Washtenaw County has the most records of venomous snakes in Michigan, 61, most of them of the eastern massasauga. Livingston County and Oakland County follow.

Washtenaw County leads with 754 records (15%), followed by Isabella County and Cheboygan County; the top five counties hold 34% of the total. 83 of Michigan's 83 counties have at least one licensed snake record.

Michigan counties with their own page: Isabella County and Washtenaw County.

Yes. Michigan has one venomous snake species on its list, the kind people usually call poisonous: eastern massasauga. Strictly, snakes are venomous (they inject venom), not poisonous (harmful to eat or touch).

Yes. One species is on the Michigan list: the eastern massasauga, with 246 licensed records. Most licensed records of the eastern massasauga come from Washtenaw County, Livingston County and Oakland County.

No. GBIF holds no copperhead record for Michigan under any license.

No. GBIF holds no cottonmouth record for Michigan under any license.

No. GBIF holds no coral snake record for Michigan under any license.

Michigan has 246 licensed records of the eastern massasauga, which ranks the state 1st of the 8 states where it reaches our threshold. Most of its licensed records in Michigan come from Washtenaw County, Livingston County and Oakland County. Range in other states and photos: Eastern massasauga profile.

Many snakes and spiders taken for venomous ones are harmless species with a similar look. These are the usual confusions, with each species' licensed records in Michigan.

No copperheads reach the Michigan list, and GBIF holds no copperhead record for Michigan under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: northern water snake (584), eastern milksnake (285), eastern hog-nosed snake (165), eastern rat snake (9) and plain-bellied watersnake (8).

No cottonmouths reach the Michigan list, and GBIF holds no cottonmouth record for Michigan under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: northern water snake (584) and plain-bellied watersnake (8).

Rattlesnakes: 246 licensed records in Michigan. Harmless species often taken for them are also on the state list: eastern hog-nosed snake (165) and eastern fox snake (67). Together they have 232 licensed records, and the two sides are recorded about equally.

No coral snakes reach the Michigan list, and GBIF holds no coral snake record for Michigan under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: eastern milksnake (285).

Widow spiders: 4 licensed records in Michigan. Harmless species often taken for them are also on the state list: triangulate bud spider (41), boreal combfoot (11), common house spider (4) and twospotted cobweb spider (3). Together they have 59 licensed records, and the lookalikes are recorded 15 times as often.

Recluse spiders are not on the Michigan list, but they are recorded in Michigan once (records of any license: brown recluse 1): treat any spider like this as venomous until identified. Harmless species often taken for them in the state: longbodied cellar spider (7) and spitting spider (2).

By count of venomous snake species, Michigan ranks 37th of 50 states, level with 8 other states. Nationally, Arizona leads with 14 species; five list none.

Every state bordering Michigan lists more venomous snake species (Michigan: 1 species; Indiana 3, Ohio 3, Wisconsin 2).

Venomous snakes listed next door but not in Michigan: the eastern copperhead (Indiana and Ohio). Listed next door and recorded in Michigan too, but too few times to list (records of any license): the timber rattlesnake, recorded here only one time (listed in Indiana, Ohio and Wisconsin). The most widely shared is the eastern massasauga, listed in all three bordering states.

Yes. One widow species is on the Michigan list: the northern black widow (4 records).

Not on our list: GBIF holds 1 brown recluse record of any license in Michigan (brown recluse 1), fewer than 10 of any one species; such records can be genuine rarities, strays, transported animals or misidentifications. Treat any spider that looks like a recluse as venomous.

Michigan has 4 licensed records of the northern black widow, which ranks the state 20th of the 30 states where it reaches our threshold. Range in other states and photos: Northern black widow profile.

Not on our list: GBIF holds 1 scorpion record of any license in Michigan (giant sand scorpion 1), fewer than 10 of any one species; such records can be genuine rarities, strays, transported animals or misidentifications. Every scorpion has venom; only the Arizona bark scorpion's sting is medically significant, and it is not on the Michigan list.