Species guide
Risso's dolphin
Grampus griseus
At a glance
Conservation, taxonomy and Madeira records reviewed . Review sources.
- Global IUCN conservation status
- Least Concern — assessment published .
Global extinction risk is separate from sighting frequency in Madeira.
- Identification
- Robust dolphin with large, square-shaped head with no beak
- Body pale grey/bluish and extensively scarred
- Size
- Maximum length: 4 m
- Recorded occurrence in Madeira
- Reported on local trips, including September 2026.
- Madeira records and season
- No dependable seasonal window established by the cited records.
Identification and size summarize profile notes updated . Local records are past observations, not a prediction of sightings.
Read the identification notes ↓- Taxonomic authority
- (G. Cuvier, 1812)
- Family
- Delphinidae
- Cetacean group
- Odontoceti
Sightings in Madeira
The 2012 checklist documents Risso's dolphin sightings and strandings. It does not establish a current local abundance or a fixed season. Historical evidence.
Our September 2026 trip report lists this species. This is an operator observation, not a population estimate.
No dependable seasonal window established by the cited records. The months in individual reports should not be treated as the limits of a season.
ID characteristics
Robust dolphin with large, square-shaped head with no beak
Body pale grey/bluish and extensively scarred
Darker flippers, fin and flukes
Tall, falcate dorsal fin
Surface behaviour
Normally travels slowly and ignores boats but sometimes is active at surface and may bow-ride or swim alongside vessels. Often surfaces at 45º angle to breathe.
Distribution
Worldwide between parallels 60º North and 60º South.
Deep tropical and warm temperate waters
Social
Groups between 3 to 50 individuals
Diet
Squid and some fish
Biometrics
Max length: 4 m
Adult weight: 300 to 500 kg
Common names in other languages
- Portuguese: Grampo, Golfinho de Risso
- German: Rundkopfdelfin, Risso-Delfin
- French: Dauphin de Risso, Grampus
- Spanish: Calderón gris, Delfín de Risso
- Italian: Grampo, Delfino di Risso
- Dutch: Gramper, Grijze dolfijn
- Polish: Delfin Risso, Delfin szary
- Swedish: Rissos delfin
- Danish: Rissosdelfin
- Norwegian: Arrdelfin, Rissodelfin
Other English names
Grey Dolphin
Names vary by language and region. This list is not exhaustive. Multilingual name records.
Review sources
Conservation, taxonomy, local occurrence and seasonality checked on . The assessment publication year is separate from this editorial review date. Identification, size, other biology notes and multilingual aliases are outside this review unless a specific source is cited alongside them.
- IUCN Red List: Grampus griseus — global species assessment, published 2018.
- Society for Marine Mammalogy: species and subspecies list (April 2026) — Scientific names, authorities, families and English names. Mysticeti and Odontoceti are treated as unranked groups.
- IUCN SSC Cetacean Specialist Group: Red List status of cetaceans — Global species categories cross-checked against the specialist group's overview, updated October 2025. Regional and subpopulation assessments are separate.
- IUCN Cetacean Specialist Group: November 2018 assessments — Global assessment publication years and category changes. A category change need not indicate a recent population change.
- Freitas et al. (2012): New records of cetacean species for Madeira Archipelago with an updated checklist — Table 1 and species accounts distinguish sightings, catches and strandings. Record totals and last-record dates describe evidence available through December 2012.
The linked trip reports document operator observations. They do not independently confirm every identification or measure population size, abundance or the probability of a sighting.