Botos_Ascom Ufra.jpeg

The Araguaian river dolphins

Portrayed in 2014, aquatic mammals are a hit among tourists who visit Mocajuba, in Northeastern Pará. Now, they are the object of a study conducted by the Federal Rural University of the Amazon, which will analyze the impacts of human interaction, with the aim of protecting them.

Eduardo Laviano

Translated by Silvia Benchimol and Ewerton Branco (ET-Multi/UFPA)


Beloved in the popular imagination of the Amazon people, river dolphins [botos] will be object of a study at the Federal Rural University of the Amazon (Ufra) that seeks to better understand the organism of river dolphins and the impact of the interactions with humans on the health of these aquatic mammals in the municipalities of Mocajuba and Cametá in Pará. 

One species which stands as protagonist of the investigation is the Araguaian river dolphin [Boto do Araguaia - Inia araguaiaensis] – a cetacean recently described in 2014. 

These mammals inhabit the region of the lower Tocantins River, produce 237 different sounds to communicate and are the third species of river dolphins cataloged in the Amazon.

Researcher Layane Maia started her investigation with river dolphins in 2015 and has closely followed the growing interest in the animals. 

She has also witnessed the intensification of tourism in Mocajuba promoted by them. 

Now, Layane is developing a doctorate research focused on the health of the species.

According to the researcher, her main scientific interest is the hormonal profile of river dolphins, to analyze their metabolic processes.

The goal is to check their stress levels, whether there are periods of the day or month when they are likely to be more agitated and what is the relationship between this stress and the sounds they produce, and what each sound signal may represent. 

"They have a very large vocal repertoire, an indication that there is a very diverse social complexity, with a lot of intelligence, similar to those of the orcas", she points out.

The study will last 36 months and is currently in the stage of testing and standardization of protocols and methodologies. 

The project will also analyze diseases and pathogen risks, as there are doubts about how well the animals' health is ensured during interactions with humans, considering both humans and river dolphins may transmit diseases to each other.

"There are well-grounded researches about whales, but not yet about river dolphins. We believe that we are going to observe influences depending on more or less visitations. As the animals are in direct context of interaction with humans, we are going to check the issues of water quality and also of pathogens in the intestines, blood and breathing tract of the animals. It will be a thorough health study, important for the preservation of the species", she says.

Study is unprecedented and challenging

Layane evaluates the operation as ambitious. First, because river dolphins are restless beings and taking them out of the water for blood testing will not be an easy task. 

Second, because scientists will need to examine the animals' spray, that is, their breathing. In river dolphins, breathing occurs through the spiracle, a small hole in the head of the animal that has a function similar to that of the nose. 

The researchers will need to momentarily cover this hole with a cylindrical container to collect the droplets exhaled at the time of breathing. 

The third challenge is to create specific methodological procedures, since this is an unprecedented study and without previous literature to ‘teach you the ropes’.

"We don't even have an estimate of the number of freshwater river dolphins in the Araguaia. Before 2014, we thought that only the pink river dolphin existed here. So, the classification of the species is still vulnerable, and we have few studies", she adds.

Professor Frederico Ozanan is also part of the Institute for Biology and Conservation of Aquatic Mammals in the Amazon (BioMA) where Layane works. 

The institute is an initiative that has gone deeper and deeper into the study of Amazonian river dolphins.

For him, cataloging the physiological parameters and organisms functionality of endemic species is important for the world to know that the Amazonian people, themselves, care about the region's ecosystem and that they are fighting to preserve it by scientific means. 

He agrees that the originality of the study represents a big challenge, but he is confident.

"They are docile animals and used to humans, but we will need to contain them a bit. This is not easy. We are still studying how all this will work out. It is a risk for those who are handling them and for the animals themselves, as they will be removed from the water. The laboratory work will be easier. There are many people, and many people will be around at the collection site, as it will take place in the center of Mocajuba. It is not possible to say that there is no risk. We have already managed other studies on river dolphins, but not in the same context", recalls Professor Ozanan, who belongs to a team of ten researchers linked to the project, which counts on the support of the Federal University of Alagoas and the Federal Rural University of Pernambuco.

Pesquisadores e botos_Ascom Ufra.jpeg
Research investigates secrets of the intelligence and health of the species that charms the region and its visitors (Ascom/Ufra)

Angélica Rodrigues, who is also a researcher at BioMA, participated in the first research group on river dolphins in the region, back in 2006. She is happy to see the work she helped to start up growing and gaining momentum.

"In the beginning, we didn't have any research that told the natural history, occurrence and ecology of the species. That is, people saw the dolphins but there was nothing systematically produced about them. The main obstacle is financial support, so in our group we help each other with both the research and also with fundraising. The North region still has little visibility when it comes to scientific research", affirms Angelica.

Hydroelectric dams and predatory fishing are obstacles to the survival of the species

River dolphins have always been pointed out as endangered species and this scenario is not different with the Araguaian river dolphins. 

This fragility is explained by the several sources of danger linked to their habitat, the rivers. The number one factor is represented by hydroelectric dams. 

According to the National Electric Energy Agency (Aneel), there are 221 hydroelectric plants operating in the Amazon. 

There are 27 classified as large, 102 as medium and small and 92 as microgenerators. Another 35 dams are under construction or on the way to construction, including in the Araguaia-Tocantins basin, where the newly discovered river dolphins live. 

"This creates a risk of geographic isolation, unfortunately. Imagine that: there is the construction of a dam where the animals will no longer be able to move along that stretch of the river, in which they used to have free access. It affects the ecosystem", says Layane Maia.

Researchers Gabriel Melo e Layane Maia have big expectations for the study (Layane Maia)
Layane Maia and Gabriel Melo are excited about the study (Personal file)

Conflicts with fishermen also add to the list. The river dolphins have powerful mobility skills and are remarkably fast and dexterous. 

This is because they do not possess a fused cervical vertebra, a characteristic that gives them great neck and head mobility, something that other dolphins and cetaceans are deprived of. 

Normally, the Araguaian river dolphins feed themselves in flooded places, such as the igapó forests, right in the middle of the aquatic roots. 

But, when the fisherman throws the net and the animal perceives the effortless opportunity of getting food, it swims hard towards the fishing equipment, bites it, turns its neck and tears the net. 

"That is, loss for the fisherman. This competition between fisherman and river dolphins is something that we need to mediate with caution", says Maia.

In addition, river dolphin meat is used as bait for fishing picaratinga in the Amazon River basin, an activity that has already led to an estimated killing of 300 to 4,000 river dolphins per year, according to the National Institute for Research in the Amazon (Inpa). 

Currently, fishing for this species, also known as “douradinha” fish, is prohibited until at least July 2, 2023. 

Institutions that promote protection of river dolphins are fighting to postpone the expiration date of the law, established in 2015 by the Ministry of Agriculture, Livestock and Supply. 

Fishing for this species is also prohibited in Colombia.

Myths and legends

The folklore that surrounds the image of “botos” is also a challenge for the animals' survival. 

The legend that they come out of the river and transform into charming men in white clothes and persuasive talk is still powerful in small towns in the interior of the Amazon region. 

The alleged magical form that the animal disguises itself and the belief that they will impregnate the girls who live along the river may cause fear and negative interactions with humans, resulting in aggression. 

According to researcher Layane Maia, reports like that are common. 

"So, all this is added: the “boto” tears the net apart, it's naughty, it emerges out of the river and shapeshifts as a man, it has human capacity and intelligence. It's very fast. There are some of its organs used in “pajelança” rituals and sometimes, if the “boto” is vulnerable, it is killed. In Cametá, there are many river dolphins with signs of aggression", she reports.

Ricardo Calazans, researcher in charge for the Mirante do Boto space, in Mocajuba, says that many fishermen do not respect the river dolphins, but that they are a minority. 

According to him, the killing of dolphins is much more common in the state of Amazonas, which has more riverside regions far from cities. 

Calazans says that many residents often alert him when they notice that a “boto” is injured.

"Here, it is very common people saying that they've danced with the boto, that they have a daughter with the boto, that the boto took a niece to a party. Still, I'd say that 90% of riverine people respect and take care of the boto", he says.

River dolphin tour enhances ecological tourism in Mocajuba

Created in 2016, Mirante do Boto is the hit of tourism in Mocajuba, a municipality in the northeast of Pará. 

They are 17 dolphins, from young to adults, that go every day to swim, play and eat near the Municipal Market of Mocajuba. 

Due to such success, the space became an official tourist place promoted by the city hall, under the responsibility of Ricardo Calazans. 

The researcher wrote a final graduation paper work focused on the river dolphins in Mocajuba, his hometown. 

Today, he is dedicated to research the habits of cetaceans and managing the place that receives up to a thousand people a week during the Amazonian summer. 

In the rainy season, the visiting flow drops to 200 people.

The river dolphins arrive around six in the morning and, at noon, they leave for the waters furthest from human contact. 

Each group of visitors interacts 10 to 15 minutes with the animals, to prevent them from becoming stressed. Tourists also feed the river dolphins.

Ricardo Calazans says he loves the
Ricardo takes care of the botos in Mocajuba, which receive up to a thousand visits a week (Personal file)

"We have to be very careful, because the food given are small portions of fish sold in the street market stands. But they don't eat all kinds of fish. We have to inspect everything beforehand, to double check if it's the ideal fish, if it has bones. They eat mapará, tucunaré and filhote. In addition to supervising the fish given, we make a previous presentation sharing some guidelines", he says.

All river dolphins have their own names and Calazans guarantees that he recognizes each one from a far distance. 

"The 17 river dolphins never show up together. We've already noticed that the fewer visitors we have, the more they show up. Some are a bit wild. But we have a daily average of 5 to 7 dolphins swimming around the market every day", he says.

Ricardo says he is excited about the research about the health of these animals. 

According to the researcher, working at Mirante has changed his life and is a reason for happiness and pride. 

"I had a friend and his father used to sell fish at the market. When I was a child, I noticed that he would always go there, grab a little fish and give it to the “boto”. As soon as I started to study at the university, I told my professor about the idea of researching the river dolphins in my city. Since then, I started to visit the place and always check out the conditions of the river dolphins, if they were fine, take care of them voluntarily. So, the city mayor hired me. I created the page on Instagram [@botosdemocajuba] and we have now more than 30,000 followers. It was an incredible thing. They are little “botos” that I love from the bottom of my heart, I fight for them and I do anything for them", he says.

Currently, Ricardo has the support of a veterinarian who monitors the health of the animals on a weekly basis. 

According to him, most of the scratches and bites that appear on the river dolphins are the result of fights among themselves. 

"Usually, there are just superficial scratches. People are invited to visit the Mirante, it's all free, but “you can't be too careful”. Here, we guide the interaction step by step. And we always ask people to preserve them. This phenomenon of the river dolphins moving towards human contact is very special and only occurs in two places in the world: here and in Manaus. So, we have to take care of them and do everything the right way", he says.

For researcher Frederico Ozanan, from Ufra, one of the great achievements of the research project will be the tourist organization of the interaction. 

"Based on the conclusions, we will be able to better control how many people per day will interact with them and how, besides nutritional control of the amount of food given to the animals. We will be able to help the city hall and environmental agencies to structure, in a safer way, the visits", he points out.