More Venomous Snakes Are Heading North but the Climate Isn't on Their Side

Reptiles, like many other animals, are susceptible to climate change. According to experts, venomous snakes are beginning to migrate north, and it's all due to rising temperatures. Because venomous creatures are cold-blooded their body temperatures can be closely linked to environmental conditions. As such, they will relocate depending on their preferred conditions.

Over the past five years, studies have found that snakes will be heading north soon due to climate change. Stat News also reported that snakebites have been on the rise as that relocation continues.

Brett Baldwin, Associate Curator of Herpetology and Kim Gray, Curator of Reptiles at the San Diego Zoo spoke to Newsweek about this phenomena.

"The big problem with climate change, specifically speaking about reptiles and birds, birds have an advantage, mammals have an advantage, reptiles have much less advantage in doing that...because of their low mobility," Baldwin revealed. "Their habitats are fragmented, which restricts their movement even more due to climate change."

Another major factor for snakes is that they are ectotherms, meaning that their body temperatures are regulated by the ambient temperature. "They can't control it. Reptiles are dependent on whatever temperature they're in, so that is a big hindrance for them. It's really critical for their metabolism and reproduction. They depend on temperature and seasonal cycles," Baldwin explained. "Temperatures are really critical along with moisture. That's supposed to be decreasing this century too." Therefore, it makes sense for snakes to migrate north so they can better regulate themselves.

Gray noted that venomous snakes have lots of niches they fit into. "So for example, what their food items are. A lot of times what you'll see with rattlesnakes in particular is that they might be tied more to where their prey is, and how their prey is impacted by climate change."

Gray brings up an interesting point. While it is theoretically possible that climate change could move snake populations north, the real world impact of those changes may make the migration a fruitless attempt at species survival.

"If you have a scenario where climate change is impacting an area more so that there's more prey items, then you might see an increase in prey," she said. "With climate change, we can estimate that these strange cyclical periods where plants respond and then thus the rodents respond, you might see some species like rattlesnakes, maybe there would be an increase in regard to the prey items."

However, as reptile populations are fragmented, "you could theorize they might move north, but it wouldn't work if there's not the prey item, there's nothing there for them to eat, or a den for them to retreat into for the winter," Gray noted. "What we're noticing is that it's difficult for any species of animal to respond to this climate change because it is happening so rapidly."

Baldwin said that rainfall affects snakes' body regulation, along with the rodent population. "It'll be a banner year for rattlesnakes if we have good rain, because there's plant growth, there's seeds, there's rodents, you have that cycle," he told Newsweek.

venomous golden lanshead snake
A highly venomous Golden Lancehead snake is seen at the Butantan Institue -which supplies the Ministry of Health, with many snakes' venom for its ditribution countrywide- in Sao Paulo, Brazil, on November 12, 2019.(Photo by CARL DE SOUZA / AFP) (Photo by CARL DE SOUZA/AFP via Getty Images

But, Gray points out, not all species are the same, exhibit the pythons in Florida back in 2008.

At the time, "there was predictive modeling saying that due to climate change pythons were going to expand their range and extend throughout the Western United States. These are invasive, non-native pythons, and come west and take over. There's been colleagues of ours that have done studies, that technically according to the climate models that could be the case. However, these animals are very specific in their niche requirements. Not only do the reptiles need the food item, they need a special place to live, they need their kind of habitat."

Baldwin and Gray also spoke about the number of snakebites increasing, which could be due to humans moving into habitats that once belonged to these serpents. "Some of these studies may reflect encroachment habitat as far as bites going up. The more we push out into our habitats, the more we encounter them, the more bites happen," Baldwin said. "Specifically with venomous snakes in the United States, there's very specific in their habitats."

"Anecdotally, it feels like there are more snake bites than in the previous years, and I think it just boils down to it's just human habitation, growth of human population and urbanization, we are moving into habitat where they historically had been," Gray noted.

"As snakes respond, maybe where there's more urbanization with rats or mice where snakes might come in, or when it's hot and dry, you might see snakes come into an area seeking water and seeking cooler."

She continued: "It's more about human-wildlife conflict resolution, and as we all face climate change, we need to be thinking more about how we can learn to help live with these animals, and live with the fact that they're there."

Perhaps the first step in living together is learning the ways in which we are alike. For example, the rattlesnake doesn't lay eggs to reproduce, it produces live young. "That is an artifact of them living in colder climates to not have to lay eggs," Gray explained. "That is the one tiny advantage that rattlesnakes do have over other reptiles. Reptiles can adapt, but that's over a millennium, they don't have the time to adapt to the rapidly changing environment at this point."

Casper Ohm, marine biologist and editor-in-chief at Water-Pollution.org.uk explained via email that snakes are starting to relocate. "Although there isn't enough research to support the northern migration of snakes as a fact, there have been increasing reports of snakes appearing where they shouldn't be, both on land and in the water," he wrote. "Climate change driven by humans combined with major weather events such as floods and wildfires had displaced many animals, including snakes which are especially sensitive to temperature changes. So faced with an inhospitable environment, which to a snake can be a few degrees, will lead them to move towards a colder climate, which is usually north."

However, snakes migrating north may not be the best solution. "Consequently, the snakes enter new ecosystems as they migrate and can unbalance the existing harmony amongst species of animals in their new habitat," Ohm continued. "Snakes are predators and their introduction into new environments can wreak havoc, both to the local ecosystem and potentially to the human inhabitants as well. Like all animals faced with climate change, snakes do migrate both by land and ocean."

He concluded: "They will travel far to find the ideal environment to settle, recent research suggesting they may all end up in Alaska by the year 2100!"