72 individuals were recognized, of which 25 were again observed between 1991 and 2000. However, three of the reviewed 160 animals were observed over 100 kilometres (62 mi) from where they were first registered. Anterior teeth are conical and later have ridges on the inside of the crown. The raise in contaminant levels of mercury have also caused and increased the total number of recorded deaths among these mammals, especially close to the gold mines, where mercury is used in the process for mining gold. The frequency of intercourse in a couple is high, and they have been observed to use at least three different sex positions – lying head to head, lying head to tail, and contacting the womb at right angles. But they are strictly freshwater mammals. Catfish and piranha are also considered a regular part of their diet and in some cases they may be observed hunting small turtles. Rolling, lob tailing and flipper waving are common behavior among these playful animals. The length of its fins allows the animal to perform a circular movement, allowing for exceptional maneuverability to swim through the flooded forest but decreasing its speed.[19]. Commerson's Dolphins ... What is the Average Lifespan of the Dolphin? According to the pink Amazon river dolphin myth, it is said that this creature takes form of a human and seduces men and woman to the Underworld of Encante. In the wild, the average life expectancy of these animals is only 33 months. The most frequently consumed fish belong to the families Sciaenidae (croakers), Cichlidae, and Characidae (tetras and piranhas). In the wild, the average life expectancy of these animals is only 33 months. It has a melon on the head, the shape of which can be modified by muscular control when used for biosonar. Adult males reach a maximum length and weight of 2.55 metres (8.4 ft) (average 2.32 metres (7.6 ft)) and 185 kilograms (408 lb) (average 154 kilograms (340 lb)), while females reach a length and weight of 2.15 metres (7.1 ft) (mean 2 metres (6.6 ft)) and 150 kilograms (330 lb) (average 100 kilograms (220 lb)). Thus, in the Amazon basin there are: 107 individuals in the Solimões River (Brazil), 346 the in the Amazon River bordering Peru and Colombia, around 260 individuals in the Mamirauá Lake system of Brazil and 13.000 individuals in the Mamirauá Sustainable Development Reserve. [34] The várzea is also a major source of income through excessive local commercialized fishing. They can also be found inhibiting the rivers of Brazil, Columbia, Ecuador and Peru. Sexual dimorphism is evident in these creatures, with the males weighing and measuring between 16% and 55% more than females. Lifespan. Unlike other dolphins having a fused vertebra, this species can freely move their neck on all sides. [34][45] The use of the Amazon river dolphin carcass as bait for the piracatinga dates back to 2000. Botos are generally concentrated below the confluences of the channels. [20][better source needed] An individual named Apure at the Duisburg Zoo, Germany, is estimated to have lived for more than 40 years, being captured from the wild at age nine. [17], The texture of the body is robust and strong but flexible. [6], The Amazon river dolphin is located in most of the area's aquatic habitats, including; river basins, major courses of rivers, canals, river tributaries, lakes, and at the ends of rapids and waterfalls. Researchers say that, this sound has some connection to food. Males are ready for mating around 7 to 12 years old. Like most other species, these dolphins sleep with one eye open. Reproduction and Lifespan. While they are mostly pink, Amazon river dolphins have various colored skins, which can be light gray, pink, or brown. [34] More importantly, the local fishermen do not report these deaths out of fear that a legal course of action will be taken against them,[34] as the Amazon river dolphin and other cetaceans are protected under a Brazilian federal law prohibiting any takes, harassments, and kills of the species.[46]. 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. They display extremely aggressive behavior: because of biting and abrasion, male dolphins often damage their fins, flukes, and blowholes. The period of birthing coincides with the flood season, and this may provide an advantage because the females and their offspring remain in flooded areas longer than males. [37], In addition to attracting predators such as the Amazon river dolphin, these high-water occurrences are an ideal location to draw in the local fisheries. 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. Like other toothed whales, they have a melon, an organ that is used for bio sonar. They are also found in the lakes, the largest tributaries of the rivers, and seasonally in the flooded rainforests. Despite small eyes, the species seems to have good eyesight in and out of the water. Density was estimated at 0.08- 0.33 animals per square kilometer in the main channels, and 0.49 to 0.93 animals per square kilometer in the branches. [6], Adult males have been observed carrying objects in their mouths such as branches or other floating vegetation, or balls of hardened clay. Later, it was shown that males were larger than females and are documented wielding an aggressive sexual behavior in the wild and in captivity. Because their vertebrae isn’t fused or connected the way other mammals are these dolphins can turn their head a full 90 degrees allowing them to fully view their surroundings. These animals are neither fast swimmers nor deep divers, often preferring to swim on the water surface. Like many other species, the botos are seldom seen leaping above the water surface. While preying in murky water, they emit series of clicking noises, 30 to 80 per second, which they use by listening to the bouncing sonar which bounces off their prey. These dolphins are known to communicate using a well structured variety of high and low range click and whistles. A high frequency of copulations in a couple was observed; they used three different positions: contacting the womb at right angles, lying head to head, or head to tail. The Amazon river dolphin (Inia geoffrensis), also known as the boto, bufeo or pink river dolphin, is a species of toothed whale classified in the family Iniidae. After mating, it is approximately 11 months later when the calf will arrive. [23], Like other dolphins, river dolphins use whistling tones to communicate. In addition, the animal can be easily identified by having a ridge on its back instead of a dorsal fin. 4) Because these marine mammals live in rivers rather than the open ocean they aren’t known to have oceanic predators such as killer whales and sharks which are known to hunt dolphins that live in oceanic saltwater environments, but they may face threats from other animals that inhibit the Amazon.