A Brazilian biologist has used an unusual method to research the biting behavior of poisonous snakes. To do this, João Miguel Alves-Nunes from the Butantan research center in São Paulo stepped on Jararaca lance vipers – the most widespread venomous snake species in southeastern Brazil – over 40,000 times using a specially made protective boot, according to a study in the journal “Nature”. This snake is the cause of most snakebites in the region and, with a total of around 20,000 poisonings per year, accounts for a significant proportion of the incidents in the country.
The behavior of snakes is a generally neglected area of research, especially in Brazil, said Alves-Nunes in an interview with the journal “Science.” Most studies do not examine the factors that cause them to bite. “When you study malaria, you can study the virus that causes the disease – but if you don’t study the mosquito that transmits it, you will never solve the problem,” he said. “I tested 116 animals and stepped on each animal 30 times.” During the test series, which lasted several days, he stepped on and next to the snakes a total of 40,480 times.
The animals were used individually at different times of the day over a longer period of time in an arena measuring approximately two square meters. After a 15-minute habituation period, the biologist wearing a safety boot randomly stepped either directly next to the snake or gently on its head, midsection, or tail. He felt 100 percent safe and none of the bites penetrated the foam-covered boots. He was only bitten during a simulation with a rattlesnake. “Unfortunately, I discovered that I am allergic to both the antivenom and snake toxins,” he said. That’s why he had to go to the hospital for a long time.
The study found that the smaller the animal, the greater the likelihood that it would bite. “In addition, the females are more aggressive and more likely to bite, especially when they are young and during the day.” The study also shows that the animals are more aggressive at higher temperatures. In addition, the likelihood of a defensive bite is much higher if you touch them on the head than if you step on the middle of the body or tail.
The researchers hope that the results will improve the distribution of antivenoms. These are often sent to larger hospitals, for which some patients have to travel far because they were bitten in places where there was no antivenom. “By combining our data with data from other studies of snake distribution, we can identify the places where the animals are more likely to be aggressive,” Alves-Nunes explained. “For example, warmer locations with a higher proportion of female snakes should be a priority for antivenom distribution.”
