Inia geoffrensis (Blainville, 1817)

Voss, Robert S. & Fleck, David W., 2017, Mammalian Diversity And Matses Ethnomammalogy In Amazonian Peru Part 2: Xenarthra, Carnivora, Perissodactyla, Artiodactyla, And Sirenia, Bulletin of the American Museum of Natural History 2017 (417), pp. 1-1 : 1-

Inia geoffrensis (Blainville, 1817)

VOUCHER MATERIAL: None.

OTHER INTERFLUVIAL RECORDS: Actiamë ( Amanzo, 2006), Jenaro Herrera (Pavlinov, 1994), Nuevo San Juan (this report), Río Yavarí (Salovaara et al., 2003), Río Yavarí-Mirím (Salovaara et al., 2003), San Pedro (Valqui, 1999), Wiswincho ( Escobedo-Torres, 2015).

IDENTIFICATION: Identifications of pink Amazon river dolphins are not problematic.

ETHNOBIOLOGY: The pink Amazon river dolphin is named chishkan piu (“reddish dolphin”) by the Matses.

Dolphins are of no economic importance to the Matses, but they are sometimes a nuisance. The Matses now purchase nylon gill nets, which they set up in rivers, streams, and lakes near their homes. Dolphins, especially Amazon pink river dolphins often steal fish caught in the gill nets, tearing holes in the nets when they do so.

The Matses traditionally believed that pink Amazon river dolphins are spirits. Pink Amazon river dolphins (but not gray dolphins) tend to follow the Matses when they travel in canoes, which make the Matses nervous.

MATSES NATURAL HISTORY: The pink Amazon river dolphin is reddish. It has a very long snout with pointy teeth and a ball-shaped lump on its forehead. Its tail is similar to that of a fish, but oriented laterally. The dorsal fin is like the keel of a canoe. They have nipples.

Pink Amazon river dolphins are found in rivers and large streams, and in ox-bow lakes and flooded forest during the high-water season. They are especially fond of deep river bends. They congregate at the mouths of streams.

Pink Amazon river dolphins swim following the river looking for fish. The may stay a long time in deep river bends and at the mouths of streams, catching fish. They chase fish down and eat them underwater. They especially chase fish close to the bank and near river beaches. When Matses travel by canoe, they follow the canoe and exhale loudly through their blowholes to scare Matses.

Pink Amazon river dolphins are most frequently seen alone, but it is also common to see a pair or a group of three. Larger numbers can be seen where large streams feed into the Río Yaquerana. They copulate on river beaches.

They eat all types of fish, especially large catfishes.

REMARKS: Matses observations about Inia geoffrensis are limited in scope but agree in several details with the scientific literature on this species, notably about their their numerical abundance at stream confluences, seasonal use of flooded forests, predominantly piscivorous diet, and uncanny habit of following canoes and frightening people (Martin and da Silva, 2004; Martin et al., 2004; Gomez-Salazar et al., 2012; Paschoal et al., 2013). We have not seen any explicit description of the copulatory behavior of this species in the wild, but the common Amazonian superstition that pink dolphins have sexual relationships with people may have something to do with mating on or near river beaches, as alleged by the Matses.