Snakebite researcher steps on vipers 40,000 times

A Brazilian biologist who wanted to find out when and why poisonous snakes bite chose an unusual method to research the topic — by stepping on or near the dangerous animals tens of thousands of times.

Joao Miguel Alves-Nunes from the Butantan Institute used jararacas — a highly venomous viper occurring across South America that is responsible for biting some 20,000 people per year — for his research.

The results gleaned from this risky endeavor in the name of science, which could save lives, were published this month in the journal Nature.

What did the study show?

In an interview with the journal Science, Alves-Nunes said that there had previously been little research on what factors cause snakes to bite.

He said that his method of treading on or near the animals — in special protective boots — had enabled him to refute the common assumption that jararacas bite only if people touched or trod on them.

"I stepped close to the snake and also lightly on top of it," Alves-Nunes said. "I didn’t put my whole weight on my foot, so I did not hurt the snakes. I tested 116 animals and stepped 30 times on every animal, totaling 40,480 steps."

The probability of a jararaca biting was inversely proportional to its size, according to Alves-Nunes. In other words, the smaller the animal, the greater the chance of its setting its fangs into someone.

The female of the species is also more aggressive than the male, the study showed, especially when they are young and during daylight hours.

The snakes were also more prone to bite during hot weather, when cold-blooded reptiles are more active and have more energy.

The chances of being bitten also rose if the snakes were touched on their heads rather than the middle of their bodies, the research showed.

Useful for deploying antivenom supplies

Alves-Nunes said that the information gleaned from the study would help mitigate the problem of snake bites in Brazil.

"With our new findings, we can predict where bites may happen and plan better antivenom distribution," he said.

"By combining our data with data from other studies showing snake distribution, we can identify the places where the animals are more likely to be aggressive. For example, warmer places with a higher female snake population should be a priority for antivenom distribution."

Snake researcher allergic to antivenom

Alves-Nunes said he felt "100% safe" while treading on or around the snakes because of the boots he wore, which  he said were chosen on the basis of advice from experienced colleagues at the institute.

However, although the jararacas did not manage to pierce the boots, he did get bitten when experimenting with a rattlesnake and had to receive treatment in hospital.

"Thankfully, I was in the best place I could be," he said, saying that the Butantan Institute was a leader in antivenom development.

But the bite did reveal an unhappy trait for a snake researcher.

"Unfortunately, I discovered that I am allergic to both antivenom and snake toxins. I had to take a 15-day medical leave," he told Science.

However, again showing his passion for knowledge at any cost, Alves-Nunes is turning the misfortune to good scientific account.

"I am now comparing the bite strength of rattlesnakes and jararacas and how resistant different materials and shoes are to them," he said.

Edited by: Darko Janjevic