Some news outlets have reported that hot, dry conditions appear to be driving rattlesnakes into Utah’s urban areas in search of moisture, but this should not be taken as the Great Rattlesnake Invasion of 2021, as some members of the public have interpreted the reports.
“I’m not arguing that people aren’t seeing the snakes. They most certainly are, but whether that represents an unusual increase in snake activity, I would be a bit surprised at that,” said USU biology professor Alan Savitzky, noting extreme heat tends to limit snake movement, if anything, because it can be too hot for snakes as well as humans.
“The paradox as far as people’s reports go,” Savitzky added, “is that if people are expecting that the high temperatures are increasing snake activity, then they may be more inclined to report that activity and start sort of cataloguing those observations.”
USU Extension wildlife specialist Terry Messmer has been the source of some of the recent news on higher snake activity, and he said he has indeed received more reports of snake sightings than usual this summer, especially early in the season. However, Messmer did not suggest the incidence was at epidemic levels and told The Herald Journal on Wednesday his intent has been to simply make people aware of possible snake encounters as opposed to cause alarm.
“They are showing up, we are getting calls from people seeing more snakes. I haven’t got any in Cache Valley, but I have got them in Spanish Fork, American Fork and the areas around Provo where folks have encountered more snakes in areas where they never saw them before,” Messmer said. “To avoid incidents, we wanted to get the word out about it. You know they are out there, they’ve always been out there, but if you encounter them in areas, just basically leave them alone and everything will be fine.”
The general thought has been snakes are becoming more active due to the high heat and drought conditions, forcing them to range farther in search of water, but Savitzky noted rattlesnakes don’t require a lot of water, and in any event he questioned whether there is more water available to them in towns than they can get in the mountains or wildlands.
“Desert snakes are adapted to living in deserts, so even under drought conditions I would be surprised if the water shortage is enough to drive snakes into surrounding neighborhoods,” he said.
And to the idea that snakes might be more active lately because they thrive in heat, Savitzky said, “While it is certainly true that snakes being reptiles are active in warm temperatures, it can be too hot for snakes as well. … My sense actually is there would probably be less activity during peak temperatures during the daytime. It’s actually too warm for many of our snakes at these very high temperatures.”
Both Savitzky and Messmer urge people who encounter rattlesnakes to simply leave them alone, and both cited statistics that show a high percentage of rattlesnake bites occur when humans try to catch, kill or harass the reptiles.
Savitzky said snakebite specialists refer to these as “illegitimate bites” because they were instigated by conscious human interference with the animals.
“There are also legitimate bites, and those are bites when the person is not trying to interact with the snake, maybe didn’t even see the snake,” he said. “Those are really rare. They are not unheard of, they are not inconsequential. They are a snakebite by a venomous snake and that is serious medical emergency that needs to be treated appropriately at a medical facility, but it is very very rarely life-threatening,” he said.
Mesmer noted that Utah averages about 12 or 13 rattlesnake bites per year, and in the past 100 years there have been six recorded deaths from bites in Utah.
He cautioned residents that it is illegal to kill rattlesnakes unless they or someone else is in imminent danger.