Massachusetts mammals

Common Bottlenose Dolphin in Massachusetts

Tursiops truncatus

Native to Massachusetts S2 Imperiled in Massachusetts

Not listed as nonindigenous in Massachusetts by USGS NAS; native to its Massachusetts range.

IUCN Red List status

  1. LC
  2. NT
  3. VU
  4. EN
  5. CR
  6. EW
  7. EX

LC – Least Concern

Widespread and abundant; not at risk.

Common Bottlenose Dolphin (Tursiops truncatus)Delfín mular (Tursiops truncatus), isla de San Cristóbal, islas Galápagos, Ecuador, 2015-07-24, DD 86Common Bottlenose Dolphin (Tursiops truncatus)Two wild bottlenose dolphins breaching in unison over gray coastal waterWild bottlenose dolphin surfacing head-on, beak and dorsal fin above the water
Photo: NASA · Public domainCommon Bottlenose Dolphin (Tursiops truncatus)Photo: Diego Delso · CC BY-SA 4.0Delfín mular (Tursiops truncatus), isla de San Cristóbal, islas Galápagos, Ecuador, 2015-07-24, DD 86Photo: Jonathan Eisen · CC BY 4.0Common Bottlenose Dolphin (Tursiops truncatus)Photo: steve b · CC0Two wild bottlenose dolphins breaching in unison over gray coastal waterPhoto: Rolf Lawrenz · CC BY 4.0Wild bottlenose dolphin surfacing head-on, beak and dorsal fin above the water

Common Bottlenose Dolphin in Massachusetts, by the numbers

Occasional in Massachusetts 60th most recorded of 93 mammals logged in Massachusetts

14 occurrence records
8 with iNaturalist photos
Aug 25, 2024 Last seen in Massachusetts

Records from 2000–2026.

When to look for the Common Bottlenose Dolphin in Massachusetts

Most sightings fall in June.

14 Massachusetts occurrence records (iNaturalist and GBIF) by month of year, 2000–2026. Shows when the species is recorded, not a guarantee of presence. Based on a small number of dated records; the seasonal pattern may not be representative.

Monthly Massachusetts records (table)
MonthRecords
January0
February0
March0
April0
May2
June4
July2
August1
September2
October0
November0
December3

Monthly common bottlenose dolphin occurrence records (iNaturalist and GBIF) in Massachusetts, 2000–2026.

Seasonality

Year-round in Massachusetts, with recorded sightings peaking in June, with a smaller rise in December.

Occurrence map

Where Common Bottlenose Dolphin has been recorded in Massachusetts

14 records mapped · zoom and drag to explore

13 Massachusetts records mapped

Where it's recorded in Massachusetts

CountyRecords
Essex County 1
Other localities 13

The complete county distribution, spread across 1 Massachusetts counties. Every occurrence record falls in one county, so these sum to the total. Counties from GBIF and US Census boundaries.

Bottlenose dolphins are more familiar from Southeast and Gulf Coast waters than New England, and Massachusetts’ thin, 14-record showing near Cape Cod National Seashore and Monomoy National Wildlife Refuge reflects a population that mostly stays farther south, only occasionally ranging this far north.

Records scatter across May, June, September, and December with no single dominant month, a pattern that fits infrequent, individual sightings rather than a predictable seasonal visitor. NatureServe ranks the species S2, imperiled, in Massachusetts, notably more precarious here than its secure global status, underscoring how marginal this part of its range really is.

Occurrence data from iNaturalist and GBIF.

Common Bottlenose Dolphin (Tursiops truncatus)
Full species profile Common Bottlenose Dolphin Tursiops truncatus Size 2–4 m6.6–13.1 ft Weight 150–650 kg330.7–1433 lb Lifespan 60 yr View the full profile

More mammals in Massachusetts in the atlas

Data & sources

The data and visualizations on this page draw on these open sources:

  • GBIFCC-BY 4.0occurrence records behind the range map, elevation, and record counts
  • iNaturalistCC0 / CC-BY / CC-BY-SAobservations, photos, and audio recordings
  • NatureServe ExplorerCC-BYthe state conservation rank
  • IUCN Red Listattributed factthe global conservation status
  • USGS NASpublic domainnative / introduced status
  • Natural Earthpublic domainthe relief basemap
  • USFSpublic domainnational-forest boundaries