Snake activity is very closely tied to weather, with temperatures being directly tied to activity levels in rattlesnakes. It probably isn’t a surprise to know warm weather generally supports increased activity in reptiles, but the temperature range activity peaks can sometimes be surprising. In 2020, I compiled and released data that displayed temperatures at time of a rattlesnake encounter and/or the temperature at time of removal by us. A couple years later, I decided to once again revisit this, and have analyzed 2022’s temperatures at time of rattlesnake removals.
In 2022, 53% of rattlesnakes removed were adults, while 46% were juveniles. A good chunk (still a bit less than half, closer to around 1/3rd) of the juveniles that make up that data are neonates born between August – October, though more were individuals from the prior year (2021) found from the beginning of the season to the end. Most adults were found between April and late September. Getting into the temperature data below, we’ll see most snakes are found & removed inside of about a 20 °F range — the same temperature range humans tend to be most active outdoors. This means the data could be somewhat skewed by the fact humans are simply outside more in this temperature range, however keep in mind, a lot of rattlesnakes removed in the data were found during inspections in which regular human activity likely wouldn’t result in a discovery.
The data is quite similar to 2020’s, not too much of a surprise given most research suggests our species of rattlesnake (the northern Pacific rattlesnake) seems to prefer temperatures around 80 °F. The data from 2022’s snake season has the following takeaways:
- more than 60% (63.5%) of rattlesnake encounters & removals occurred between temperatures of 75 – 89 °F
- rattlesnake activity drops off pretty rapidly beyond 90 °F,
- the 20 degree range from 70 – 90 °F is where over 3/4 of rattlesnake encounters occur
When we differentiate between adult and juvenile rattlesnakes, the data shows a slower drop off in juveniles being encountered or removed in high temperatures when compared to adults. 82% of adult rattlesnake encounters occurred between temperatures of 70 – 89 °F, 10% more than juveniles in the same temperature range. One thing to note about juvenile rattlesnake data is two batches of newborn baby rattlesnakes were removed in the 80 – 84 °F range, leading to the notable spike in numbers there.
The big takeaway from this differentiated data is that most adult (larger) rattlesnakes seem to prefer the same temperature range humans also enjoy for outdoor activity. Juveniles are also largely seen in the same ideal temperature range, but given their inexperience, it seems they can be found during much hotter weather. Quite a few of the juvenile rattlesnakes found in high temperatures were digesting, though the same also goes for many of the large rattlesnakes also found in the higher temperature range the data extends to. The low end of the temperature range rattlesnakes were removed amidst in 2022 were in the first month & last month of the snake season, in addition to cool overnight temperatures deeper in the snake season.
Aside from narrating over the graphical data, it mostly speaks for itself. I’ll likely post another set of data in 2024 or 2025 depending on whether or not anything stands out on the back end. This (2023) season will prove interesting following a rather significantly prolific wet season.
