The Tonina or Inia geoffrensis of the family Iniidae is a odontoceta of cetaceans (that is, provided with teeth instead of whales that are mystical mystical cetaceans) of fresh water, typical of the Amazon River and the basins of the Orinoco River and its main tributaries. Therefore, it is found in Bolivia, Brazil, Colombia, Ecuador, Peru and Venezuela, that is, in all the countries where these rivers flow.
The three subspecies recognized today consider the different geographical location of these dolphins: Inia geoffrensis geoffrensis occupies the entire central part of the Amazon River; Inia geoffrensis humboldtiana is found in the Orinoco basin in Venezuela and Colombia and Inia geoffrensis boliviensis as its name says in Bolivia.
Its habitat is represented not only by the main river but also by small channels, mouths, lakes and even just below waterfalls and rapids. In practice, the presence of the pink dolphin in one area and not in another is determined exclusively by the presence of food and, therefore, by the level of water: during the dry season, the inia is concentrated in the main water channels. richer water, while during the season The rain also moves gently towards the secondary arms, also venturing into flood plains and flooded forests.
It was observed that there is a habitat preference between males and females of pink dolphin: while men tend to stay in the main channel, with a very high level of water, women tend to stay with the smaller ones in the zones of the inside. This seems to be dictated by the fact that in the secondary waters the currents are less impetuous and, therefore, the smaller ones are less dangerous, the catches of the fish and, therefore, the teaching are also easier; in addition, they can be attacked less frequently by both adult males and other predators
CHARACTER, BEHAVIOR AND SOCIAL LIFE
The inia are solitary animals and the only groups are those formed by the mother with her children (usually the mother with two children of different ages). However, it is possible that, for short periods of time, small groups are created for mating or feeding, even if seen in captivity, that hierarchies are not established within the groups. However, the inia can be associated with other animals besides its species, such as the sotalia (Sotalia fluviatilis), another species of river dolphin or the giant otter (Pteronura brasiliensis) to hunt together
It has been observed that the inia is a very active cetacean both day and night and is a particularly sociable and playful animal, so much so that it can be easily approached by anyone (see the video below), even if it is much more difficult to tame the dolphins bottlenose dolphins.
The inia are not cetaceans who love to change often the place they tend to frequent so much that they are considered sedentary animals. In any case, their migrations are linked to the water level, therefore to the stations, which obviously conditions the greater or lesser presence of food.
COMMUNICATION AND PERCEPTION
The inia, like all dolphins, use echolocation (the same sonar mechanism that exploits the reflection of sound waves) to identify obstacles, understand how depths are structured and locate prey. In practice, the inia emits sounds at a frequency between 16-170 Hz that are also used to communicate between individuals of the same species.
EATING HABITS
The inia has an extremely varied diet and has been found to include about forty different species of fish that vary in size from 5-80 cm (20 cm average), including river turtles because their teeth are so strong that they they allow breaking. also a carapace or a shell of a crab.
The diet of the pink dolphin varies according to the season, in fact, during the rainy season, when it becomes more difficult to catch fish given the great abundance of water and, therefore, the fish are more dispersed, satisfied with what they find during the dry season. When the density of the fish is greater, they become much more selective.
The inia is a solitary hunter and usually hunts in the morning between 9.00 and 10.00 or in the afternoon between 3.00 and 4.00. Sometimes the fast society form with another species of river dolphin Sotalia (tucuxi) or giant otter (Pteronura brasiliensis) to fish fish in a coordinated manner, especially when dealing with banks. This search is favored by the fact that the tastes of each species are, in fact, very different, so at the end of the hunt there is no competition over what one species has to eat compared to the other.
REPRODUCTION AND GROWTH OF THE SMALL
Little is known about the sexual habits of this pink dolphin. It has been observed in captivity that the males are very aggressive with the females at the time of mating. This is also highlighted by the fact that all men have both scars due to damaged stings and fins and this suggests that in the wild the struggle to mate with a female must be quite hard and bloody. Therefore, this conclusion suggests that the inia are not monogamous cetaceans.
Observations about their coupling modalities were observed in captivity where it was seen that the male courts the female, making her turn, biting her. If a woman is not in heat, these male attentions respond aggressively. The man, however, is particularly tenacious and insists until he is killed. Always in captivity it was observed that in the course of 3.5 hours they mate fifty times and in different positions.
The females reach sexual maturity when they reach a length of 160-175 cm, while the males reach a length of approximately 200 cm, which correspond to about 5 years of age of the pink dolphin.
In general, the mating takes place between June and August and after approximately 11 months, only a small weight of 6-7 kg of approximately 80 cm long is born. Therefore, births occur in the period when the rivers are rich in water (May-July) and, therefore, the females can move in the lateral channels. This fact brings several advantages: as the waters are reduced, there is a greater concentration of fish and, therefore, it is easier to fish for both the mother and the baby.
The small dolphins are breastfed for about a year, but they stay with their mother for at least 3 years and this means that the mother is often pregnant while breastfeeding the baby.
DEPREDATION
In fact, it has no natural enemies. Sometimes the black alligator (Melanosuchus niger) or the anaconda or the jaguar or the catfish (families Cetopsidae and Trichomycteridae) can disturb it.
STATE OF POPULATION
Inia geoffrensis is classified in the IUCN red list of animals Data Deficient (DD) that is, there is no adequate information to make a direct or indirect evaluation of its extinction risk based on the distribution and / or the state of The population In fact, in the areas in which the INIA is designed will have a lot of information, however, these areas are only a very small part, but the territorial extent is not representative of this whale, and it is for this reason that its evaluation is considered "insufficient data".
The species is listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora, known simply as the "Washington Convention") that includes species not necessarily threatened with extinction, but whose trade must Control yourself to avoid exploitation incompatible with your survival.
SOCIAL, ECONOMIC IMPORTANCE IN THE ECOSYSTEM
It was noted that, although the type of fish you eat is not a particularly caught variety, in reality this pink dolphin is seen as a calamity by fishermen as rips fishermen's nets to steal the fish.
They are not, in fact, the species hunted by the Amazonian populations. At the most we have seen that if some specimens are dead, we take the fat to use as an oil for illumination or as part of their body for folk medicine; however, the use of your flesh or skin is not known. This fact should not surprise us because in the Amazon people there are many legends about these pink dolphins who are granted supernatural powers and for this reason they are respected and protected.
In contrast, inias are known among local populations to help fishers channel fish into networks
