A boldly patterned dolphin of shallow seas around southern South America and elsewhere.
The head, flippers, dorsal fin and tail region are black, contrasting with white areas around the middle of the body.
At the Santa Cruz River estuary in Patagonia, Commerson’s dolphins linked their behavior to the tide. Researchers recorded activity from shore viewpoints and surveyed by boat, dividing the estuary into one-square-kilometre cells to compare habitat use. Diving occurred more often on the ebb, and the habitat models indicated a preference for shallow water inside the estuary.
The authors suggested that these dives could be benthic foraging. The observations offer a close view of how dolphins may use a river mouth where currents and water depth shift with the tide. But this was one estuary in Argentina, and the researchers did not identify prey during every dive. A feeding explanation is an interpretation of observed behavior, not direct confirmation of what each dolphin was eating.
IUCN Red List · Least Concern (LC) · Global species-level assessment
The 2017 global IUCN assessment lists Commerson’s Dolphin as Least Concern (LC), assessed on 22 August 2017; the global population trend is recorded as Unknown. The assessment says the South American subspecies is widespread and abundant in major parts of its range, while the Kerguelen subspecies is separately listed as Endangered in a regional assessment. The global category therefore does not describe every local population or subspecies equally.