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Terrapene carolina carolina
A Relict Population Doomed To Extinction?
Thermochron iButton Use and Misuse
in Box Turtle Research
iButton installed on 10/8/15
removed 4/22/16
This chart demonstrates several uses of a properly used Thermochron iButton temperature logger.
Turtle M19 was chosen for this example because he always uses the exact same stump hole for hibernation, and has consistant hibernation dates year to year, so the air and soil temperature loggers could be installed in the correct locaton prior to hibernation, and the iButton could be installed while the turtle was still active prior to hibernation
It's clear by looking at the chart, that the iButton was not recording the correct air temperatures while above ground. The reason it was recording substantally higher temperatue is because it was being hit by direct sunlight (solar insulation), even in the woods, and even with small sunflecks. It's not a waste, though, as it records within 4 hours when this turtle went under ground and when he emerged.
wired thermocouple glass alcohol and mercury thermometers
solar insolation
Box turtles use their carapaces and plastrons for thermoregulation by basking in full sunlight and using the soil as a heatsink when in forms and in hibernation. In my study turtles, I measure carapace temperatures using an infrared thermometer, and plastron temperatures using a thermister probe at soil/plastron interface while in a form, but this is only done once every 3 or 4 days, and only once per each visit.
Dallas (Maxim) Thermochron Ibuttons can be programmed to record temperatures at any interval up to 256 minutes and can be read and re-launched nearly an unlimited number of times over the 10 year lifetime of the internal lithium battery.
Ibuttons are about the size of 4 stacked dimes and are used elsewhere in turtle research, primarily (if sometimes used improperly to record air temps) to record soil/carapace temperatures of a turtle during hibernation. (See website)
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