Solinia

(Blainville, 1817) COMMON NAME: Boto, Pink River Dolphin

The Boto is a mammal included in the Cetacea order, Odontoceti suborder and Iniidae family. The scientific name is Inia geoffrensis.

The pink river dolphin is the largest cetacean to spend its time in fresh waters. The Boto is a bulky mammal but with a body with a very hydrodynamic structure. There is no dorsal fin but rather a longitudinal ridge on its underside which is somewhat similar to a keel of a boat. The Boto’s pectoral fins are particularly prominent and are used for balance during movement. The pink river dolphin possesses a small face with a prominent front head and long beak with heterodont dentition (different types of teeth; conical and molar). While functional the eyes are small and rounded, their eyesight is poor but they are not blind as some consider.

Un-fused neck vertebrae give them more flexibility than other dolphins being able to rotate their head up to 180 degrees. This is used to their advantage during flood seasons to maneuver around and in-between trees to catch prey.

The colour of this species varies from bright pink to dusty grey, however the juveniles are completely grey.  Reproduction and births happen the all year.

The pink river dolphin is active day and night and can be observed during air intake at the water’s surface, during feeding, playing or reproductive activities, it does not leap or jump out of the water.

DISTRIBUTION AND ABUNDANCE

The pink river dolphins are found in a variety of freshwater habitats in the Peruvian Amazon Basin and especially in the Pacaya-Samiria National Reserve where they are abundant. They live in white waters (Marañón), black waters (Samiria), clear waters, confluences of rivers and also lakes. There have been sightings in the upstream Marañón and Ucayali, limited from going further by the strong currents and fresh waters close to the Andes.

Peruvian pink river dolphins do not have large migration patterns; it seems that their mobility is limited to familiar hunting or reproductive grounds; it appears that they do not have the willingness or desire to swim long distances.

Generally, they are observed swimming alone or in a pairs (mother with the calf). However groups of up to 19 specimens have been encountered at one time.

This species is one of the most abundant river dolphins but abundance and seasonal distribution should be confirmed by more extensive studies. Population appears to be stable in Peru but a more constructive conservation effort is required now to prevent any population decrease due to the current threats.

IUCN Red List Category: (2011) DATA DEFICIENT (DD) due to the limited amount of current information available. In Peru there are no recent publications relating to the pink river dolphin and research is needed to better evaluate the impact of threats in order to design effective conservation measures.

The species is in Appendix II of CITES.