Giant snakes and humans live complex relationship in the world, but attacks are rare

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On November 25, a five-year-old boy escaped an attack by a ten-foot python in Australia after his grandfather and father managed to free the child from the reptile. And in October, a missing 54-year-old woman was found in the belly of a reticulated python (Python reticulatus), in Indonesia, about seven meters long.

Despite appearing in recent news, however, attacks by giant snakes on humans are rare.

Snakes known as great constrictors include pythons, boa constrictors, anacondas and related species, some of which can reach ten meters in length and up to 200 kg as adults.

They feed on prey up to 15% to 25% of their total weight, including medium-sized mammals such as pigs and calves, and kill by constriction—that is, they suffocate animals slowly and swallow prey whole. This is because the bones that form the skull and jaw of snakes are connected by elastic ligaments that allow the mouth to open up to three times the total diameter of the animal itself.

Therefore, its presence in some parts of the world can cause fear. Giant snakes are found in Australia, parts of Asia (including all of Southeast Asia and Indonesia), sub-Saharan Africa, and South and Central America. But given their abundance, cases of fatal attacks on humans are uncommon — eight cases have been confirmed over the last 27 years.

Its occurrence, however, is far more shocking than other more lethal statistics, such as the 500 deaths on average attributed to hippos each year.

As humans are not part of the snakes’ traditional diet, the accidents that occur, according to experts, are fortuitous, and generally increase when there is loss of forested area and difficulty for the reptiles to find other prey.

“We are not part of the diet, this is absolutely accidental. I won’t say that there are no proven reports, but in general we only see the inflated belly. If you were to consider all the stories that are released, [os ataques] are much rarer”, explains the chief biologist of the Selva Viva Project, in Taubaté (SP), Marcus Buononato.

He, who has worked at the Butantan Institute, in São Paulo, recalls that accidents occur when there is a lack of knowledge about the biology and behavior of these animals.

“What is considered by humans as aggressiveness in other animals is simply a defense mechanism. If given the opportunity, the snake will defend itself, and the way it does that is by attacking”, he says. “And for them, we are considered predators, not the other way around.”

As they are nocturnal animals, snakes are also guided more by scent than by sight, yet another factor that excludes “chasing” by humans as an innate behavior of these reptiles.

“What happens more frequently is that the humans who live there, because they have a life of work on the farm or in the fields, carry the smell of other animals, such as pigs and livestock, on their clothes and in their homes. So the snakes look for by the smell and end up causing accidents in humans”, he explains.

In addition to this mistaken attribution of an animal’s defense behavior as a premeditated attack, relationships between humans and snakes in different parts of the world have evolved in a much more complex way over the last tens of thousands of years. Who explains this relationship is the herpetologist (specialist in reptiles and amphibians) Harry Greene, professor at the University of Austin (Texas).

Author of a 2011 study published in the scientific journal PNAS (Proceedings of the National American Society) that analyzed prey, predator and competition relationships between snakes and hunter-gatherer natives of the Philippines, known as Agta (pronounced “a- yeah”), Greene claims that, out of 16 attacks in four decades, only 6 were fatal (four adults and two children).

More often, according to the herpetologist, it is humans who feed on animals, and not the other way around.

“Successful predation on humans was much rarer, being much more common to see cases of giant snakes that fed on prey also eaten by humans and, more often, humans hunting the snakes to either feed on them, or use the leather,” he explains.

It is not known for sure what happened in the accident with the victim in Indonesia, whether she was attacked by the snake or whether she was in the “wrong place at the wrong time” — the most likely hypothesis, according to Greene.

“Like most vipers [serpentes venenosas]boa constrictors and pythons look for good places to ambush their prey, using their chemosensory organs [glândulas especiais nas escamas labiais que captam luz infravermelha]. Sometimes, in the search for food, they find prey. [que podem ser humanas] and then they kill and eat,” he says.

For Greene, it is also possible that many giant snakes in the past fed on great apes, including hominids that are now extinct, but this was rare. “It was more a question of opportunity to meet,” he says.

As the ancient populations that inhabited the islands of the Pacific did not generally exceed 1.5 m in height and around 40 kg, it would not be difficult for these animals to feed on humans.

Buononato also reinforces that the disclosure of these extremely rare cases in an alarmist way can harm the preservation of animals. “Brazil is a huge country, with a large forested area and several places where anacondas and boa constrictors are found. If there were a high frequency of these attacks, there would be many official records, but no one ever manages to present evidence of a death by anacondas. a tendency to always give more emphasis to what is negative”, he says.

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