The issuance of these sounds is related to the time they return to the surface before diving, suggesting a link to food. Unfortunately not much is known about the social structure of these river dolphins. [8], The relatively long duration of breastfeeding and parenting suggests a strong mother-child bond. Because their cervical vertebrae are not fused, they can move their head up to 180 degrees, which is helpful for hunting in shallow waters and floodplains. Despite small eyes, the species seems to have good eyesight in and out of the water. In studies conducted during the rainy season, the density observed in the flood plain was 18 animals per square km, while on the banks of rivers and lakes ranged from 1.8 to 5.8 individuals per square km. Like many other dolphins, the Amazon dolphins are not acrobatic, and it is difficult to train them. 9) Rather than a tall dorsal fin these dolphins have a low triangular hump-shaped ridge down the middle of their back. Apparently, there is little competition for food between these species, as each prefers different prey. Anterior teeth are conical and later have ridges on the inside of the crown. Skin Color: Color is dependent on their age. Bottlenose Dolphins. Catfish and piranha are also considered a regular part of their diet and in some cases they may be observed hunting small turtles. It has also been observed that captive dolphins share food. Amazon River dolphins have an important role as predators of the river, and prey on a range of fish species, thus controlling their populations. They communicate in a variety of ways, all nonverbal. The intervals between sightings ranged from one day to 7.5 years. In the wild, Amazon river dolphins live an average of 30 years. The animals have been treated with suspicion by local people. Sexual dimorphism is very evident, with males measuring 16% longer and weighing 55% more than females. 5) The amazon river dolphin is also sometimes referred to as the Boto dolphin. The lifespan in captivity ranges from 10 to 30 years. Take your favorite fandoms with you and never miss a beat. The pink dolphins are known to prey upon the piranhas, the legendary terror of the Amazon. An Amazon river dolphin named Apure lived for forty years at the Duisburg Zoo in Germany. The IUCN recognizes three subspecies:[9]I. g. geoffrensis (Amazon river dolphin), I. g. boliviensis (Bolivian river dolphin), and I. g. humboldtiana (Orinoco river dolphin);[6] while the Committee on Taxonomy of the Society for Marine Mammalogy only recognizes the first two of these. The breeding period occurs in October - November, while the gestation period lasts approximately 11 months. The Botos are most active in the early morning and late evening. Beaks: The beaks are pretty long with a strong built adapted to capture prey. They have not yet been officially declared as threatened or endangered. [38][39][40][32][41][42][43][44] The local fishermen overfish and when the Amazon River dolphins remove the commercial catch from the nets and lines, it causes damages to the equipment and the capture, as well as generating ill will from the local fishermen. The average gestation period (the period from conception to birth) for amazon river dolphins is about 9 months. The color of adults varies between solid and mottled pink and in some adults the dorsal surface is darker. It is also the largest river dolphin species in the world. Due to the fact that these dolphins live in shallow river waters their main threats are humans. After mating, it is approximately 11 months later when the calf will arrive. There is one albino on record, kept in an aquarium in Germany. Reproduction and Lifespan.