Early emergence has begun!

As sunny 70+ degree days have been warming the ground recently, body temperatures of the telemetered rattlesnakes have been creeping up… but only from the 50-60F range into the higher 60s. Then, yesterday, I found Female 41 laying in the grass next to the log where she has spent the past two winters. But just being visible doesn’t constitute emergence.

I returned late this morning and found Female 39 visible for the first time, basking in dappled sun under the end of the log where she has spent the past two winters.

IMG_0091; 16 February 2016
This was all that was visible of Female 39 this morning but it takes only a small surface area in the sun to act as a radiator and warm the entire snake.

Then, not only did I find that Female 41 had moved about 20 feet from her winter shelter to a smaller nearby log, but I watched as Male 49, a large non-telemetered animal with white/green paint in his rattle, arrived at the same log and joined her. Although they coiled next to each other, I saw no actual courtship behavior during the 45 minutes I watched.

IMG_0117.CR2; 16 Feb 2016
Male 49, just a few feet from joining Female 41 this morning. Without a transmitter, I have no way of determining his body temperature or knowing where he spent the winter. An encounter with him is purely chance but white/green paint in his rattle makes him easily recognizable.

Body temperatures of Males 37 and 38, both of which spent the winter high on the bluff north of the preserve, were around 90F at midday today. Because their winter locations are almost inaccessible, I don’t know if they have actually left their hibernacula but they were both definitely in the sun today. Remember that ground temperature is much higher in the sun than the air temperature, particularly on south-facing slopes.

As of today, the other five telemetered rattlesnakes remain relatively cool and out of sight and the weather forecast looks like cloudy skies, cooler temps, and more rain over the next few days.

The study animals did not begin to leave their winter shelters until the end of the first week in March last year. Although this is three weeks earlier than last year, it is certainly a limited emergence with many snakes remaining underground and inactive. But the fact remains that some rattlesnakes have left their winter shelters, so “rattlesnake season” is definitely underway.

Remember that being careful where you place your unprotected hands and feet and leaving snakes alone when you find them would prevent almost all rattlesnake bites!