Guiana dolphin
Sotalia guianensis
A small grey dolphin rising through brown estuary water. Guiana dolphins go where the fish are, and no sighting is ever a promise.
Near Threatened (IUCN, 2018) means it is close to qualifying as threatened. It was moved up from Data Deficient because fishing and habitat loss along its coast are a concern. French Guiana lists it as Endangered locally.
Photos show the species, not always the places on this page.
Length
Up to about 2.1 m (6.9 ft); usually smaller than a bottlenose dolphin
Weight
The heaviest recorded is about 121 kg (267 lb); I did not find a typical adult weight
Next to a person
Up to about as long as a tall adult, and at the heaviest as heavy as one to two adults
What it eats
Opportunistic feeders, taking more than 60 species of schooling fish, mostly small ones of about 20 cm or less, plus shrimp, squid and crabs. Hunting methods vary between communities.
Around people
Calm, give space
How it lives
Females mature at about 5 to 8 years and males at about 7. Gestation lasts about 12 months, with a calf roughly every 2 years. Growth layers in the teeth suggest they can live more than 40 years. In French Guiana, aerial surveys found groups, with 146 dolphins in 39 groups over eight flights.
Where it goes
A coastal and estuary dolphin. In French Guiana it uses the whole coast, mostly rocky sites and the largest river mouths such as the Maroni, Kourou, Cayenne, Mahury, Approuague and Oyapock. The sources I read do not describe a set migration.
We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.
Populations
There is no global count. Around Cayenne in French Guiana, aerial surveys (2013 to 2019) and boat surveys (2017 to 2018) gave an estimate of about 128 dolphins (95% range 70 to 235), or 0.80 per square kilometre. French Guiana lists the species as Endangered locally, and of 43 stranded dolphins from 2014 to 2020, bycatch was the main identifiable cause of death. I found no abundance estimate for Guyana. Elsewhere, Guanabara Bay in Brazil fell from about 400 dolphins in 1985 to 34 in 2016, and a 2021 study of Lake Maracaibo in Venezuela estimated about 180 caught in nets each year.
Meet it respectfully
Keep a slow, steady course and let the dolphins decide the distance. Never chase, surround, touch, feed or bait them, and give mothers and calves extra room. Fishing nets are a main danger in their waters, so keep clear of nets. I did not read local watching rules for Guyana or French Guiana, so follow your guide.
Fun fact
Tap the bulb to light it up.
It was once treated as the same species as the river-dwelling tucuxi. It is now a separate species that lives in coastal waters and estuaries.
Scientists have found it has an electroreceptive sense, a way of detecting weak electric fields.
Growth layers in the teeth suggest it can live more than 40 years.
Guiana dolphin in the Ocean Atlas
Places we have researched where this animal is recorded. It is never guaranteed, and some places are for watching from the boat only.
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French Guiana
GuyanaSources for this page
- Mammal Diversity Database, Sotalia guianensis, 2026
- Latin American Journal of Aquatic Mammals, Guiana dolphin in French Guiana, 2022
- Frontiers in Marine Science, Guiana dolphin in Lake Maracaibo, 2021
- Wikipedia, Guiana dolphin, 2026
Facts checked 5 October 2026. Photos: Unsplash licence, or Creative Commons as shown on each photo.
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