Venomous snakes and spiders in Connecticut
Connecticut has two venomous snake species among the 14 snake species listed there: eastern copperhead and timber rattlesnake. The eastern copperhead accounts for the most records (82), and venomous species make up 13% of all 1,163 licensed snake records in the state. On the spider side, one species is medically significant: northern black widow.
Venomous snakes of Connecticut
Connecticut's venomous snakes are one copperhead or cottonmouth species and one rattlesnake species. Together they account for 146 licensed records; the eastern copperhead alone has 56% of them, and the least recorded, the timber rattlesnake, has 64.
Dangerous spiders of Connecticut
One widow species (Northern black widow: 1 record) is on the Connecticut list. There is no recluse spider on the Connecticut 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.
Other snakes recorded most in Connecticut
These eight account for 78% of all licensed snake records in Connecticut; the most recorded, the common garter snake, alone for 27%.
All 14 snakes of Connecticut →
Other spiders recorded most in Connecticut
These eight account for 40% of all licensed spider records in Connecticut; the most recorded, the orchard orbweaver, alone for 8%.
All 86 spiders of Connecticut →
When are snakes out in Connecticut?
Observation records of snakes in Connecticut run mostly April through October, peaking in May with 22% of them. December through February together hold under 2% of the records, so snakes in Connecticut are rarely recorded in winter. Venomous snakes alone have nine observation records with a month in Connecticut, too few for a season of their own.
When spiders are most active in Connecticut
Observation records of spiders in Connecticut run mostly April through October, peaking in June with 20% of them. Winter (December to February) holds 3% of the records.
Counties with the most venomous snake records
New Haven County has the most records of venomous snakes in Connecticut, 67, most of them of the eastern copperhead. Litchfield County and Middlesex County follow.
| # | County | Records | Most recorded there |
|---|---|---|---|
| 1 | New Haven County | 67 | Eastern copperhead |
| 2 | Litchfield County | 41 | Timber rattlesnake |
| 3 | Middlesex County | 20 | Timber rattlesnake |
| 4 | Hartford County | 10 | Eastern copperhead |
| 5 | Fairfield County | 8 | Eastern copperhead |
Where in Connecticut are snakes recorded most?
New Haven County dominates: 38% of the state's licensed snake records come from it alone, and the top five counties hold 86%. 8 of Connecticut's 8 counties have at least one licensed snake record.
| # | County | Records | Share |
|---|---|---|---|
| 1 | New Haven County | 446 | 38.3% |
| 2 | Middlesex County | 177 | 15.2% |
| 3 | Litchfield County | 158 | 13.6% |
| 4 | Fairfield County | 119 | 10.2% |
| 5 | Hartford County | 99 | 8.5% |
| 6 | New London County | 73 | 6.3% |
| 7 | Tolland County | 55 | 4.7% |
| 8 | Windham County | 36 | 3.1% |
Connecticut county with its own page: New Haven County.
Are there poisonous snakes in Connecticut?
Yes. Connecticut 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).
Are there rattlesnakes in Connecticut?
Yes. One species is on the Connecticut list: the timber rattlesnake, with 64 licensed records. Most licensed records of the timber rattlesnake come from Litchfield County, Middlesex County and Hartford County.
Are there copperheads in Connecticut?
Yes. One species is on the Connecticut list: the eastern copperhead, with 82 licensed records. Most licensed records of the eastern copperhead come from New Haven County, Fairfield County and Hartford County.
Are there cottonmouths (water moccasins) in Connecticut?
No. GBIF holds no cottonmouth record for Connecticut under any license.
Are there coral snakes in Connecticut?
No. GBIF holds no coral snake record for Connecticut under any license.
Eastern copperhead (Agkistrodon contortrix)
Connecticut has 82 licensed records of the eastern copperhead, which ranks the state 17th of the 27 states where it reaches our threshold. Most of its licensed records in Connecticut come from New Haven County, Fairfield County and Hartford County. Range in other states and photos: Eastern copperhead profile.
Timber rattlesnake (Crotalus horridus)
Connecticut has 64 licensed records of the timber rattlesnake, which ranks the state 10th of the 30 states where it reaches our threshold. Most of its licensed records in Connecticut come from Litchfield County, Middlesex County and Hartford County. Range in other states and photos: Timber rattlesnake profile.
Harmless lookalikes in Connecticut
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 Connecticut.
What looks like a copperhead in Connecticut
Copperheads: 82 licensed records in Connecticut. Harmless species often taken for them are also on the state list: northern water snake (152), eastern milksnake (94), eastern hog-nosed snake (48) and eastern rat snake (44). Together they have 338 licensed records, and the lookalikes are recorded 4 times as often.
What looks like a cottonmouth in Connecticut
No cottonmouths reach the Connecticut list, and GBIF holds no cottonmouth record for Connecticut under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: northern water snake (152).
What looks like a rattlesnake in Connecticut
Rattlesnakes: 64 licensed records in Connecticut. Harmless species often taken for them are also on the state list: eastern hog-nosed snake (48). It has 48 licensed records, and the two sides are recorded about equally.
What looks like a coral snake in Connecticut
No coral snakes reach the Connecticut list, and GBIF holds no coral snake record for Connecticut under any license, so a snake taken for one here is most likely a harmless lookalike. Those recorded in the state: eastern milksnake (94).
What looks like a widow spider in Connecticut
Widow spiders: 1 licensed record in Connecticut. Harmless species often taken for them are also on the state list: triangulate bud spider (12), boreal combfoot (9) and common house spider (5). Together they have 26 licensed records, and the lookalikes are recorded 26 times as often.
What looks like a recluse spider in Connecticut
No recluse spiders reach the Connecticut list, and GBIF holds no recluse spider record for Connecticut under any license, so a spider taken for one here is most likely a harmless lookalike. Those recorded in the state: longbodied cellar spider (7) and spitting spider (3).
How Connecticut compares
By count of venomous snake species, Connecticut ranks 29th of 50 states, level with 7 other states. Nationally, Arizona leads with 14 species; five list none.
Of the three states bordering Connecticut, New York lists more venomous snake species; Massachusetts lists as many (Connecticut: 2 species; New York 3, Massachusetts 2, Rhode Island 0).
Venomous snakes listed next door but not in Connecticut: the eastern massasauga (New York). The most widely shared are the eastern copperhead and the timber rattlesnake, each listed in two of the three bordering states.
Are there poisonous spiders in Connecticut?
Does Connecticut have black widows?
Yes. One widow species is on the Connecticut list: the northern black widow (1 record).
Does Connecticut have brown recluse spiders?
No. GBIF holds no brown recluse record for Connecticut under any license.
Northern black widow (Latrodectus variolus)
Connecticut has 1 licensed record of the northern black widow, which ranks the state 28th of the 30 states where it reaches our threshold. Range in other states and photos: Northern black widow profile.
Are there scorpions in Connecticut?
No. GBIF holds no scorpion record for Connecticut under any license. Every scorpion has venom; only the Arizona bark scorpion's sting is medically significant, and it is not on the Connecticut list.
More for Connecticut
GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.