Biologist catches rattlesnake swimming in river in Pantanal; see video A rattlesnake (Crotalus durissus) was spotted swimming in the Piquiri River, in the Encontro das Águas State Park, in the Northern Pantanal of Mato Grosso. The record was made by biologist Giovanna Leite during an expedition that aimed to observe otters in the region. ? Also follow Terra da Gente on Instagram According to her, the video was recorded during the return to the Cuiabá River, after the sighting of the otters. "It was a chance encounter. We were walking in search of the otters and then, when we finished our sighting of the otters, we went back to the Cuiabá River, and at that moment we ended up finding the rattlesnake. It was a very unexpected encounter and it was incredible", says Giovanna. See more news from Terra da Gente, on g1: IT'S NOT ALWAYS THE MOTHER: Meet animals in which the parents take care of the puppies SCIENCE: Dogs alter the behavior of pumas in protected areas, study reveals WATCH VIDEO: Giant otter is caught devouring huge cachara in the Pantanal; see video Single species, different subspecies In Brazil, there is only one species of rattlesnake, Crotalus durissus, the same one spotted swimming in Piquiri. "What varies between the different regions are the subspecies, which present small differences in geographic distribution and in some morphological characteristics", explains Giovanna. Rattlesnake (Crotalus durissus) Douglas Ribeiro/iNaturalist A rare but not unknown behavior Despite impressing those who see it for the first time, swimming rattlesnakes are not a new phenomenon to science. This is what biologist Daniela Sifuentes explains, who has worked for many years in the study of snakes. "Yes, there are several records of rattlesnakes swimming. Although it is not a behavior observed as frequently as in aquatic snakes, they are perfectly capable of crossing rivers, lakes and other bodies of water when necessary", says Daniela. Rattlesnake is caught swimming Giovanna Leite According to her, the ability to swim is practically universal among snakes — what changes is the degree of adaptation to the aquatic environment. "The rattlesnake swims very well and uses water mainly as a means of moving between areas. Despite this, it is not an aquatic snake, as is the case with anacondas, which have specific adaptations to live most of their lives in water", he says. The expert also draws attention to a factor that may be making this type of incident more common: the expansion of the species' distribution area. "A study showed that around 34% of the expansion of the area occupied by the rattlesnake is related to the increase in pastures, while 23% is explained by the reduction in rainfall during the coldest quarter of the year, which made new regions suitable for the species", says Can she bite while swimming? The swimming technique recorded in the video is the same as the rattlesnake uses on land. Snakes can move in different ways, such as serpentine movement — the famous "S" — or straight movement, among others, and the rattlesnake is capable of using more than one type of displacement. The difference is that, in the water, this sinuous movement propels the body forward by pushing the water backwards. A frequent question when faced with images like this is whether the snake would be able to defend itself in the water. For biologists, everything indicates yes. "We believe so. As it is an animal that swims only on the surface of the water, keeping its head out, and not diving like some aquatic snakes do, if it needs to defend itself, it will probably be able to bite", they explain. VIDEOS: Highlights Terra da Gente See more content about nature on Terra da Gente