Venomous snakes and spiders in Maryland

Maryland's venomous snakes are one copperhead or cottonmouth species and one rattlesnake species. Together they account for 176 licensed records; the eastern copperhead alone has 82% of them, and the least recorded, the timber rattlesnake, has 32.

Two widow species (Northern black widow: 37 records, Southern black widow: 25 records) are on the Maryland list. There is no recluse spider on the Maryland 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 78% of all licensed snake records in Maryland; the most recorded, the northern water snake, alone for 16%.

These eight account for 33% of all licensed spider records in Maryland; the most recorded, the orchard orbweaver, alone for 7%.

Observation records of venomous snakes in Maryland run mostly April through September, peaking in June with 29% of them. December through February together hold under 2% of the records, so venomous snakes in Maryland are rarely recorded in winter.

Observation records of spiders in Maryland run mostly April through October, peaking in August with 16% of them. Winter (December to February) holds 3% of the records.

Montgomery County has the most records of venomous snakes in Maryland, 54, most of them of the eastern copperhead. Frederick County and Prince George's County follow.

Prince George's County leads with 817 records (23%), followed by Montgomery County and Anne Arundel County; the top five counties hold 64% of the total. 23 of Maryland's 23 counties have at least one licensed snake record.

Maryland counties with their own page: Anne Arundel County, Baltimore County, Frederick County, Harford County, Howard County, Montgomery County and Prince George's County.

Yes. Maryland has two venomous snake species on its list, the kind people usually call poisonous: eastern copperhead and timber rattlesnake. Strictly, snakes are venomous (they inject venom), not poisonous (harmful to eat or touch).

Yes. One species is on the Maryland list: the timber rattlesnake, with 32 licensed records. Most licensed records of the timber rattlesnake come from Frederick County, Garrett County and Allegany County.

Yes. One species is on the Maryland list: the eastern copperhead, with 144 licensed records. Most licensed records of the eastern copperhead come from Montgomery County, Prince George's County and Baltimore County.

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

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

Maryland has 144 licensed records of the eastern copperhead, which ranks the state 10th of the 27 states where it reaches our threshold. Its observation records in Maryland run mostly April through September, peaking in June; most licensed records come from Montgomery County, Prince George's County and Baltimore County. Range in other states and photos: Eastern copperhead profile.

Maryland has 32 licensed records of the timber rattlesnake, which ranks the state 21st of the 30 states where it reaches our threshold. Most of its licensed records in Maryland come from Frederick County, Garrett County and Allegany County. Range in other states and photos: Timber rattlesnake 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 Maryland.

Copperheads: 144 licensed records in Maryland. Harmless species often taken for them are also on the state list: northern water snake (589), eastern rat snake (560), eastern milksnake (110), eastern hog-nosed snake (102) and corn snake (15). Together they have 1,376 licensed records, and the lookalikes are recorded 10 times as often.

Cottonmouths are not on the Maryland list, but they are recorded in Maryland once (records of any license: northern cottonmouth 1): treat any snake like this as venomous until identified. Harmless species often taken for them in the state: northern water snake (589).

Rattlesnakes: 32 licensed records in Maryland. Harmless species often taken for them are also on the state list: eastern hog-nosed snake (102). It has 102 licensed records, and the lookalikes are recorded 3 times as often.

No coral snakes reach the Maryland list, and GBIF holds no coral snake record for Maryland under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: eastern milksnake (110).

Widow spiders: 62 licensed records in Maryland. Harmless species often taken for them are also on the state list: common house spider (92), triangulate bud spider (42), boreal combfoot (33), twospotted cobweb spider (1) and false black widow (on record). Together they have 168 licensed records, and the lookalikes are recorded 3 times as often.

Recluse spiders are not on the Maryland list, but they are recorded in Maryland eight times (records of any license: brown recluse 8): treat any spider like this as venomous until identified. Harmless species often taken for them in the state: longbodied cellar spider (22) and spitting spider (1).

By count of venomous snake species, Maryland ranks 29th of 50 states, level with 7 other states. Nationally, Arizona leads with 14 species; five list none.

Of the four states bordering Maryland, Pennsylvania and Virginia list more venomous snake species; West Virginia lists as many (Maryland: 2 species; Pennsylvania 3, Virginia 3, West Virginia 2, Delaware 1).

Venomous snakes listed next door but not in Maryland: the eastern massasauga (Pennsylvania). Listed next door and recorded in Maryland too, but too few times to list (records of any license): the northern cottonmouth, recorded here only one time (listed in Virginia). The most widely shared is the eastern copperhead, listed in all four bordering states.

Yes. Two widow species are on the Maryland list: the northern black widow (37 records) and the southern black widow (25 records).

Not on our list: GBIF holds 8 brown recluse records of any license in Maryland (brown recluse 8), 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.

Maryland has 37 licensed records of the northern black widow, which ranks the state 4th of the 30 states where it reaches our threshold. Its observation records in Maryland run mostly April through September, peaking in June; most licensed records come from Harford County, Frederick County and Prince George's County. Range in other states and photos: Northern black widow profile.

Maryland has 25 licensed records of the southern black widow, which ranks the state 10th of the 22 states where it reaches our threshold. Range in other states and photos: Southern black widow profile.

No. GBIF holds no scorpion record for Maryland under any license. Every scorpion has venom; only the Arizona bark scorpion's sting is medically significant, and it is not on the Maryland list.