Reptile experts are baffled by a python attack in an apartment in New Brunswick that left two young boys dead, with autopsies scheduled for today that hope to shed light into the incident that has led to cautions about exotic pets.

Noah Barthe, 5, and Connor Barthe, 7, were killed by the large African rock python while visiting an apartment upstairs from Reptile Ocean in Campbellton on Monday morning, RCMP say.

Steven Benteau, a spokesman for the Department of Natural Resources, told CBC News on Tuesday that African rock pythons are not permitted under the province's Exotic Wildlife Regulation.

A criminal investigation has been launched.

In the meantime, the shocking attack has baffled even snake experts.

"It’s strange, I’m just trying to piece it together," says Lee Parker, the facilities manager at Ontario reptile zoo Reptilia. "They don't go on killing sprees … it doesn't make sense to me."

Jeff Reynolds, manager at the Reptile Store in Hamilton, says: "The [African rock python] is not overly aggressive, not any more aggressive than your larger-type snake. I find it very bizarre that it would attack two [kids]."

Such deadly attacks aren’t unheard of, but are rare.

The last attack on a human by an African rock python was in 2002, when it killed and swallowed a 10-year-old boy in Durban, South Africa. Three years earlier, a smaller rock python killed a three-year-old boy after escaping its enclosure in Centralia, Ill.

The species is the largest in Africa, sometimes growing as long as six metres.

RCMP said the Campbellton python measured between 3.5 and 4.5 metres, and weighed approximately 45 kg. Officials have euthanized the snake.

Laws regulating the types and sizes of snakes allowed as pets vary across Canada, changing from one community to the next.

Parker points to Guelph, Ont., which allows non-venomous snakes up to three metres long, but nearby Richmond Hill prohibits any pythons or boa constrictors.

But even if your municipality allows them, Parker advises against buying these exotic pets.

"We don't recommend people keep large snakes as pets because of the potential threats," he says. "Burmese pythons, anacondas, boa constrictors … these are dangerous pets."

Snake safety

Parker says some customers looking to buy snakes clearly don’t know what they’re getting into.

"I’ve turned people away," he says. "Parents come in and they just want to buy a snake to shut their kid up. I say, 'What if he loses interest, stops feeding it, will you take over?' and they say, 'No, we just want to keep him quiet.'

RCMP said the Campbellton python measures between 3.5 and 4.5 metres, and weighs approximately 45 kg. (iStock)

"Other people say they want one because it’s cool," he says. "They shouldn’t be buying a snake. And they can probably get one somewhere else, but I won’t sell to them."

Unprepared owners sometimes create an ecological threat, as pet snakes are released into the wild and an unprepared ecosystem. The problem has recently arisen in the Florida Everglades, where the African rock python has established itself as an invasive species with no natural predators.

Parker wants more owners to do their homework. "Definitely make sure you know what type, how big it's going to get," he cautions. "You always have to make sure you know what that animal's capabilities are, how strong it is."

He warns that many people underestimate snakes and the threat they can pose.

The most vital aspect of snake safety: Don’t feed or handle one alone.

Parker says a large python (over three metres long) can quickly surprise its handler and knock them out with a squeeze around the head or neck, cutting off air and blood flow. Children are even more vulnerable, he warns, and shouldn’t be left alone with a large python under any circumstances.

Proper enclosures are crucial as well. Snakes are strong and wily, accustomed to creeping into small spaces, so a simple plastic container or box isn't sufficient, Parker says.

It's still not known how the Campbellton python escaped the store.

No charges have been laid as RCMP handle the criminal investigation.