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Snakes and spiders in Norfolk County, Massachusetts

Norfolk County, home of Dedham, has 8 snake and 47 spider species on record, from 193 licensed snake and 352 spider records. Venomous species here: the eastern copperhead and the northern black widow.

8snake species
47spider species
2venomous
Bitten in Norfolk County? Call 911 for a venomous snakebite or any bite with trouble breathing. For advice on any bite or sting, call Poison Help at 1-800-222-1222 (free, 24/7, U.S.-wide). Do not cut the wound, suck out venom or use a tourniquet. General information, not medical advice. Do not handle or try to identify a snake or spider by this page; if unsure, treat it as venomous.

Are there venomous snakes or spiders in Norfolk County?

Yes. The eastern copperhead: 9 licensed records, 75% of all Massachusetts records of it. The northern black widow: 101 licensed records, 62% of all Massachusetts records of it.

What snakes are in Norfolk County?

In all, 8 snake species are on the Norfolk County list. The most recorded are the common garter snake (106), the northern water snake (33) and the eastern milksnake (14). Norfolk County holds more than half of all Massachusetts records of the eastern copperhead.

#SpeciesRecordsShare of Massachusetts records
1Common garter snake
Thamnophis sirtalis
10610%
2Northern water snake
Nerodia sipedon
3310%
3Eastern milksnake
Lampropeltis triangulum
1410%
4Eastern copperhead venomous
Agkistrodon contortrix
975%
5DeKay's brown snake
Storeria dekayi
810%
6Ring-necked snake
Diadophis punctatus
89%
7Eastern racer
Coluber constrictor
711%
8Eastern ribbonsnake
Thamnophis saurita
11%
Source: GBIF records located in Norfolk County (GADM level 2), read 2026-09-29. Listed from records under any license; counts are CC0/CC BY only.

When are snakes out in Norfolk County?

Observation records of snakes in Norfolk County run mostly April through September, peaking in April with 23% of them; across Massachusetts the peak is May.

January: 0 observation records (0%)JanFebruary: 0 observation records (0%)FebMarch: 1 observation record (1%)MarApril: 32 observation records (23%)Apr23%May: 31 observation records (22%)May22%June: 24 observation records (17%)Jun17%July: 12 observation records (9%)Jul9%August: 16 observation records (11%)Aug11%September: 14 observation records (10%)Sep10%October: 10 observation records (7%)Oct7%November: 0 observation records (0%)NovDecember: 1 observation record (1%)Dec

What spiders are in Norfolk County?

In all, 47 spider species are on the Norfolk County list. The most recorded are the northern black widow (101), the familiar jumping spider (20) and the nursery web spider (19). Norfolk County holds more than half of all Massachusetts records of the northern black widow.

#SpeciesRecordsShare of Massachusetts records
1Northern black widow venomous
Latrodectus variolus
10162%
2Familiar jumping spider
Platycryptus undatus
208%
3Nursery web spider
Pisaurina mira
197%
4Bold jumper
Phidippus audax
168%
5Orchard orbweaver
Leucauge venusta
134%
6Drumming sword wolf spider
Gladicosa gulosa
1113%
7Garden spider
Araneus diadematus
119%
8Filmy dome spider
Neriene radiata
1011%
9Sixspotted fishing spider
Dolomedes triton
1015%
10Spined micrathena
Micrathena gracilis
813%
11Triangulate bud spider
Steatoda triangulosa
811%
12Boreal combfoot
Steatoda borealis
618%
13Dark fishing spider
Dolomedes tenebrosus
612%
14Dimorphic jumper
Maevia inclemens
66%
15Flea jumping spider
Naphrys pulex
67%
16Wetland giant wolf spider
Tigrosa helluo
623%
17Flower crab spider
Mecaphesa asperata
58%
18Bronze jumper
Eris militaris
46%
19
Dysdera crocata
47%
20Zebra spider
Salticus scenicus
45%
21Cone-shaped orbweaver
Cyclosa conica
317%
22
Paraphidippus aurantius
39%
23
Pholcus manueli
321%
24Broad-faced sac spider
Trachelas tranquillus
215%
25Common house spider
Parasteatoda tepidariorum
23%
26Longbodied cellar spider
Pholcus phalangioides
26%
27Parson spider
Herpyllus ecclesiasticus
23%
28Rabid wolf spider
Rabidosa rabida
25%
29Spotted orbweaver
Neoscona crucifera
24%
30American green crab spider
Misumessus oblongus
14%
31Black laceweaver
Amaurobius ferox
13%
32Black purse-web spider
Sphodros niger
117%
33Black-and-yellow argiope
Argiope aurantia
11%
34Brilliant jumping spider
Phidippus clarus
13%
35Garden ghost spider
Hibana gracilis
14%
36Grayish jumping spider
Phidippus princeps
12%
37
Pseudeuophrys erratica
17%
38Spitting spider
Scytodes thoracica
16%
39White sac spider
Elaver excepta
14%
40White-jawed jumping spider
Hentzia mitrata
14%
41Whitebanded crab spider
Misumenoides formosipes
11%
42Banded garden spider
Argiope trifasciata
——
43Marbled orbweaver
Araneus marmoreus
——
44
Pachygnatha tristriata
——
45Potter's grass spider
Agelenopsis potteri
——
46Sixspotted orbweaver
Araniella displicata
——
47Tuftlegged orbweaver
Mangora placida
——
Source: GBIF records located in Norfolk County (GADM level 2), read 2026-09-29. Listed from records under any license; counts are CC0/CC BY only.

When are spiders out in Norfolk County?

Observation records of spiders in Norfolk County run mostly April through October, peaking in August with 23% of them, the same peak as Massachusetts as a whole.

January: 2 observation records (1%)JanFebruary: 0 observation records (0%)FebMarch: 2 observation records (1%)MarApril: 21 observation records (6%)AprMay: 46 observation records (13%)May13%June: 63 observation records (18%)Jun18%July: 26 observation records (7%)Jul7%August: 80 observation records (23%)Aug23%September: 60 observation records (17%)Sep17%October: 34 observation records (10%)Oct10%November: 18 observation records (5%)NovDecember: 0 observation records (0%)Dec

What stands out in Norfolk County

Species for which Norfolk County holds a large share of all Massachusetts records: the northern black widow, 62% (101 of 162); the sixspotted fishing spider, 15% (10 of 65).

Common in Massachusetts, not on the Norfolk County list

Among the snakes most recorded across Massachusetts, these do not reach the county list: the smooth green snake (41 statewide), the red-bellied snake (32 statewide), the timber rattlesnake (14 statewide) and the eastern hog-nosed snake (12 statewide). Few records here can mean the species is rare in the county, or that few people have looked.

Harmless lookalikes in Norfolk County

Copperheads are on the county list, and so are harmless species often taken for them: the northern water snake and the eastern milksnake. Cottonmouths are not on the Massachusetts list, but GBIF holds 2 cottonmouth records of any license in Massachusetts (northern cottonmouth 2), 2 of them in Norfolk County: treat any snake like this as venomous until identified. Harmless species often taken for them here: the northern water snake. Coral snakes are not on the Massachusetts list, but GBIF holds 1 coral snake record of any license in Massachusetts (eastern coral snake 1): treat any snake like this as venomous until identified. Harmless species often taken for them here: the eastern milksnake. Widow spiders are on the county list, and so are harmless species often taken for them: the triangulate bud spider, the boreal combfoot and the common house spider. Recluse spiders are not on the Massachusetts list, but GBIF holds 1 recluse spider record of any license in Massachusetts (brown recluse 1): treat any spider like this as venomous until identified. Harmless species often taken for them here: the longbodied cellar spider and the spitting spider.

Norfolk County among Massachusetts counties

By licensed snake records Norfolk County ranks 3rd of 14 Massachusetts counties with any.

Other Massachusetts counties with their own page: Middlesex County, Worcester County, Essex County, Barnstable County, Plymouth County, Dukes County and Suffolk County.

The whole state: venomous species in Massachusetts, all snakes, all spiders.

GBIF records read 2026-09-29. Listed: any license. Counted: CC0/CC BY only. How we count.

About these numbers

A species is listed for a state once GBIF holds at least 10 records of it located inside the state by coordinates, under any license. Every count, share, month and county shown is computed only from records published under CC0 or CC BY, so a listed species can show few or no counted records. Monthly patterns show when people record snakes and spiders, which also reflects when people are outdoors. Venomous status follows taxonomy: pit vipers and coral snakes; widow and recluse spiders; the Arizona bark scorpion. Records filed under older names count for the species they belong to today. Full methodology.