Iniidae

Iniidae is a small family of toothed whales within the order Cetacea, commonly referred to as river dolphins. The family currently contains the genus Inia, with two extant species: Inia geoffrensis, known as the Amazon river dolphin or bufeo, and Inia boliviensis, the Bolivian river dolphin. Some classifications treat Inia boliviensis as a subspecies of Inia geoffrensis, reflecting ongoing questions about species limits based on genetic and morphological data.

Distribution and habitat

Inia geoffrensis inhabits the Amazon and Orinoco river basins in northern South America, preferring large, murky rivers and floodplain systems. Inia boliviensis occurs mainly in the Madeira River region and adjacent rivers in Bolivia and Brazil, with ranges overlapping portions of the Amazon basin. Both species occupy freshwater environments and can tolerate brackish conditions near estuaries, but they are primarily river dwellers adapted to turbid, constrained waters.

Description

Iniids are relatively large river dolphins with elongated snouts, small eyes, and a robust body. Their skin can exhibit pinkish to gray coloration, more pronounced in some individuals. A distinguishing feature is a dorsal ridge rather than a tall dorsal fin. They rely heavily on echolocation to navigate and hunt in sediment-filled rivers where vision is limited.

Behavior and diet

They are social animals, typically observed in small groups. Their diet consists mainly of fish and crustaceans, caught using echolocation to locate prey in noisy, turbid waters. Calves depend on maternal care for an extended period after birth.

Conservation

River dolphins in the Iniidae family face threats from habitat loss, water pollution, dam construction, and bycatch in fishing gear. They are protected by national laws in range countries, and the IUCN lists concerns about their status, prompting ongoing conservation efforts to preserve river ecosystems and reduce human-caused mortality.