Cold-blooded creatures do not care anything about calendars and official dates, but they are pretty sensitive about the photoperiod and temperatures.
It is now officially fall for us calendar-keeping humans. Reptiles probably know this in a way, the instinctive observation of the daily length of daylight (what we call the photoperiod) and what the air and ground temperatures have been lately.
Snakes, lizards, turtles and other reptiles don’t take measurements or read instruments and record data about temperatures and daylight length, but their bodies react to changes in these and trigger hormonal messages that affect their behavior.
Shorter days contribute to falling temperature averages, and these lower temperatures combine with shorter days to biologically suggest to reptiles that their comfy days out and about are running seasonally short. Their bodies tell them that winter is coming on and they soon had better take cover in the form of brumation.
Brumation is the reptile form of warm-blooded animals’ hibernation. It is a kind of suspended animation in which cold-blooded varmints go dormant, sort of “turning off” until warmer days return with regularity in the coming spring.
Critters like snakes, whose blood essentially takes on the temperature of their surroundings, clearly are not made for keeping themselves warmer than their environment. You will not see a warm winter coat of fur on a serpent.
Even cold-blooded animals cannot function in really cold temperatures, so they burrow down in the soil, leaf litter, deteriorating wood and other material and zonk out for the coldest months of the year. Their brumation habitat shelters them somewhat from the coldest temperatures, but they can survive rather brittle temperatures for periods without actually freezing and perishing.
If snakes had wings, maybe they would not need to brumate. They could migrate long distances to find appropriate temperatures and food to enjoy through winter. Realities being what they are, however, a snake needs to find a place to hole up from the cold nearby. They could be doing that right now and in the next few weeks.
Snakes in particular could be slithering closer to hibernaculum — habitat in which to brumate — during this early fall period. About the time that the first hard frosts occur, they can be expected to make the move into sleepy time shelter. At first, they may be in and out based on conditions hour by hour, but about the time that freezing weather prevails, most reptiles are underground and well into the torpor that helps shield them from winter.
The classic illustration of the short-range cold-blooded migration to hibernaculum in this region is the autumn closure of the “Snake Road” at Larue-Pine Hills Research Natural Area in Illinois’ Shawnee Natural Forest off Illinois Route 3 near Wolf Lake.
At Larue-Pine Hills, a limestone bluff formation at the edge of upland habitat lies immediately adjacent to a swampy wetland. At the base of the bluff lies Forest Service Road 345, the gravel-surfaced Snake Road.
When the twice-yearly reptile migration occurs, the movement of a wealth of snakes going to or from brumation habitat on the upland bluff side of the road is remarkably apparent. The number of snakes vulnerable on the road is such that for weeks in the fall and spring the road is closed to vehicle traffic to prevent many slinky critters from being killed or disturbed.
This time of year, the Snake Road already is closed. It shuts down Sept. 1 and remains blocked off to vehicles through Oct. 30. It is during those weeks that biologists expect virtually all the migrating snakes, lizards, salamanders and whatnot to complete their fall trek to sleeping quarters in the highlands.
A wide variety of species are found at Larue-Pine Hills, and the proximity of swamp and rocky-faced highlands contributes to possible encounters with both wetland and upland varieties. For instance, among pit vipers, it is possible to find cottonmouths, copperheads and even timber rattlers crossing the same gravel byway.
A 2.8-mile section of FSR 345 is barricaded to vehicles throughout these two months, but that does not mean you cannot travel it on foot. A fair number of people — primarily folks that appreciate slithery wildlife — are attracted to Snake Road hikes during the shutdown.
While a stroll past a possible variety of migrating serpents sounds like a nightmare to some folks, it can be a fascinating hike for those with an interest in herpetology.
It is quite safe if one pays at least some attention to where one walks. Visitors are not allowed to molest the snakes. Collecting is prohibited. The snakes are not interested in interacting with hikers.
After all, the reason why snakes are crossing FSR 345 is just to get to winter quarters … on the other side.
• Looking ahead, Thursday brings the first of October (already, good grief), which brings the beginning of raccoon and opossum hunting seasons. These seasons come in advance of the general furbearer season, which includes trapping as well as hunting of ’coons, ’possums and other furbearers, that begins Nov. 16.
Oct. 1 also is the first day during which crossbow hunting also includes wild turkeys as well. The crossbow season for deer opened Sept. 19. The early segment of turkey hunting via crossbow runs Oct. 1-18. Crossbows also can be used to take turkey during the early fall shotgun turkey seasons Oct. 24-30.
Steve Vantreese is a freelance outdoors writer. Email outdoors news items to email@example.com or phone 270-575-8650.