They’ve even been the subject of movies. In some incidents in nature, they cause fear and amazement, but, due to their magnificence, they stand out in the animal kingdom. All over the world there are four species of anacondas, all with records in South America (and three are found in Brazil). According to specialists, the bene anaconda is the only one that has not been registered in Brazilian biomes to date and can only be seen in Bolivia (watch the video above).
Juliana Terra, PhD in ecology from the University of São Paulo (USP) and coordinator of a project aimed at anacondas in the Bonito region (MS), explains that although the four species have their particularities, they all share some characteristics in common. Are they:
- Murinus Eunectes (Green anaconda)
- Eunectes Notaeus (Yellow Anaconda)
- Eunectes beniensis (Anaconda de bene)
- Eunectes deschauenseei (Mottled anaconda)
Sucuri shows her tongue after being spotted by a documentary filmmaker in Rio de Bonito, Mato Grosso do Sul — Photo: Cristian Dimitrius/Imagem
“These species are always found associated with aquatic environments, where they carry out their activities such as hunting and reproduction, among others. So much so that the genus of anacondas is Eunectes, a Greek word. If you separate the ‘I’, this means good and easy; and ‘ Nektes’ means swimmer, that is, he is a good swimmer”, explains Juliana.
Green anaconda – Murinus Eunectes
Green anaconda – Eunectes murinus — Photo: Daniel De Granville / Photo in Natura
Eunectes murinus is known as the true anaconda, but specifically as the green anaconda, because it has a background color that is an olive green. This color tone can even be a little darker or lighter, reaching a brown hue.
“It is the species of anaconda with the most information available so far. It has a wide geographic distribution and can be found widely in South America in countries such as Venezuela, Colombia, Paraguay, Ecuador, Bolivia, Peru, French Guiana, Suriname and Brazil”, emphasizes Juliana.
Also according to the expert, green anaconda are not often found in the south of South America, with Paraguay probably being the southern limit of their distribution. An interesting feature of the species is the mating system.
“Mating is quite different. It is a polyandrous and aggregating system, called the reproduction cake, that is, it is a female that releases the pheromone that attracts one or more males. They find the females through chemoreception and they can stay with up to more than 10 males in the cake. As females are much larger than males, people often confuse the males in the breeding cake with chicks, and think it’s a nest, when in fact they are reproducing adults.” says Juliana.
Heavy and long, the green anaconda is also the largest species of anaconda that exists. Males can reach an average of 3.5m in length, while adult females can reach 5m. In rarer cases, they can reach larger sizes, up to 6m.
“Due to the imposing and large size of the females, they always appear to be larger than they are. They all have sexual dimorphism, that is, males are always smaller than females”, says Juliana.
As for food, large adult females can feed on medium-sized mammals. For males, water birds are important food resources.
Yellow anaconda – Eunectes Notaeus
Yellow anaconda – Eunectes notaeus — Photo: Ernane Junior/Foto
The yellow anaconda, which may also be known as the Pantanal anaconda, has the scientific name Eunectes Notaeus. It has this name because it has a yellowish background color. The species occurs in wetlands of the Paraguay and Paraná river basins:
“In the Paraguay basin, it occurs in the Pantanal region, which covers Mato Grosso do Sul and Mato Grosso, as well as Paraguay and Bolivia. In the Paraná basin, however, it can be found in flooded areas in Argentina”, he reports.
According to the specialist, it is a species that is considered large. Females can reach a maximum of 4 meters in length and males around 2.5m. Females can also feed on medium-sized animals and waterfowl are also prey consumed by both sexes.
Anaconda de Bene – Eunectes beniensis
Bene anaconda – Eunectes beniensis — Photo: Lutz Dierken/Image
According to the specialist, Sucuri de bene, as a scientific name Eunectes beniensis, is named after the place from which it was identified – in the Department of bene, in Bolivia, and soon after, in the same country, in the Department of Pando.
As for morphology, it falls between the two previous species (yellow and green anacondas). So much so that the first individuals were considered hybrids of these two species. It is a snake little studied and therefore very little basic information about the biology of this animal is known.
As for size, the species is considered medium-sized. Adult males measure around 2 meters in length and females around 3 meters.
Spotted anaconda – Eunectes deschauenseei
Spotted Sucuri – Eunectes deschauenseei — Photo: Haddad Jr V et al. Sucuris: Biology, Conservation, Reality and Myths of one of the greatest Serpents in the World/Image
In Brazil, the mottled anaconda – Eunectes deschauenseei are found in seasonally flooded areas in the state of Pará, Ilha de Marajó, Santarém and Amapá, in the Lower Amazon region. In addition to Brazil, it can be found in French Guiana.
In terms of morphology, it is between the yellow and green anacondas, resembling a little more yellow. This, as well as the Sucuri de bene, is another species that has been very little studied and has little information from field observations:
“Basic information about the natural history of the species is lacking, such as diet, activity, reproduction, use of the environment – all this basic information is extremely important to be weighed in conservation plans, for example”, he stressed.
Of the four species of anacondas, this is possibly the smallest of them. Males barely reach two meters and females around 3 meters. But it is important to emphasize that both for the bene anaconda and for the mottled one, there are few records and little work with these animals:
“So we need a greater number of observations of this snake in the field in nature, more information on specimens to know what size these animals can reach”, he concludes.