Species: Sotalia fluviatilis
Tucuxi belong to the Mammalian Order Cetacea, in the suborder
Odontoceti. All toothed whales belong to the suborder Odontoceti,
which is Latin for "toothed whales". This dolphin belongs to the
oceanic dolphin family, Delphinidae. Other members of this family
include the killer whale, long-beaked common dolphin, and pilot
whale. The tucuxi's scientific name is Sotalia fluviatilis. The
generic name, Sotalia, is of unknown origin. The specific name,
fluviatilis, mean “of a river”, referring to the estuarine and
riverine habitats preferred by this species. The animal’s common
name “tucuxi”, pronounced “too-koo-shee”, is derived from the Tupi
language of the Mayanas Indians. The Tupi and Guarani are the
indigenous peoples of Coastal Brazil, the Amazon River, and
Northeastern South America. Two ecotypes of this species exist, a
riverine tucuxi, Sotalia fluviatilis fluviatilis, and a marine
tucuxi, Sotalia fluviatilis guianensis. The riverine ecotype
inhabits the Amazon River and its tributaries, while the marine
ecotype lives throughout the coastal regions of Honduras to Brazil.
The tucuxi looks similar to the bottlenose dolphin, with bluish gray
coloration dorsally, and lighter gray ventrally for the marine
ecotype, and pinkish white for the riverine ecotype. However, the
tucuxi differs drastically in size from the bottlenose dolphin. It
is much smaller, usually growing no larger than six feet in length.
In fact, the tucuxi is one of the two smallest species of
Delphinidae. The other species is Hector’s dolphin, Cephalarhynchus
hectori, which is endemic to the coast of New Zealand. The riverine
ecotype is even smaller, growing to about four feet in length. The
tucuxi ranges from 95-120lbs in weight.
The tucuxi’s range includes the Amazon River and its tributaries, as
well as the coastal regions and estuaries of northeastern South
America, along the Caribbean Sea and Atlantic Ocean. This species
prefers a wide range of habitats, preying on a variety of
noncommercial freshwater and saltwater fishes.
Tucuxis live in groups of 10-15 individuals, but it is not uncommon
to see smaller groups consisting of a female and calf, or larger
groups of 50-60 individuals. No social interactions between tucuxis
and Amazon River dolphins, Inia geoffrensis, have been documented.
Gestation is estimated at 11-12 months. Calving peaks in October and
November for the riverine ecotype, during the low water period of
the Amazon. The marine ecotype calves during the winter. Newborns
are range 2-3ft in length.
The development of the Amazon River region greatly impacts this
species. The construction of dams especially disrupts river ecology.
Entanglement in fishing gear is also a threat. Fortunately, tucuxis
do not compete with humans for the same fish species. Tucuxis prey
on noncommercial fish species. Other human activities endanger
dolphins, such as pollution. The worldwide population is unknown.