Winter Behavior of the Eastern Box Turtle, Terrapene C. Carolina L., in Eastern Tennessee

University of Nebraska - Lincoln DigitalCommons@University of Nebraska - Lincoln

USDA National Wildlife Research Center - Staff U.S. Department of Agriculture: Animal and Publications Plant Health Inspection Service

January 1970

WINTER BEHAVIOR OF THE EASTERN BOX TURTLE, TERRAPENE C. CAROLINA L., IN EASTERN TENNESSEE

Richard A. Dolbeer usa

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Dolbeer, Richard A., "WINTER BEHAVIOR OF THE EASTERN BOX TURTLE, TERRAPENE C. CAROLINA L., IN EASTERN TENNESSEE" (1970). USDA National Wildlife Research Center - Staff Publications. 160. https://digitalcommons.unl.edu/icwdm_usdanwrc/160

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ping turtle, Chelydra serpentina. Ibid. 166: TABLE1. DISTANCFS(in meters) OF TURTLE 491498. (Terrapene c. carolina) MOIEMENTS(21 Octobel- -. 1970b. Observations on females and eggs of the common snapping turtle, Chelydra 31 January). serpentrna. Am. hfidl. Nat. 84:69-76. Turtles C. L. Y~\~TEMA,Department of Anatomy, Up- Date 8 16 54 56 169 state ~\.lerlzcal Center, Syracuse, ,Veru York 13210. 21 Oct 23 25 28 IYINTEK BEHAVIOR OF THE EASTERN 1 Nov BOX TIJRTLE, TEHRAPENE C. CARO- LINA L., IN EASTERN TENNESSEE.-A 2 3 field study of winter movements and depths 4 and types of hibernacula of the eastern box 5 turtle, Terrapene carolina carolina L., was undertaken from October 1968-January 1969. 8 The study was confined to 23 acres (9.2 10 hectares) within the University of Tennessee's 16 Cherokee Woodlot, located 1.6 km south of 17 Knoxville, Tennessee. The area consists of 22 denselv wooded hills in which a remnant 23 of the original forest remains (Shanks and 25 Norris, 1950). Trees are primarily deciduous 1 Dec with oaks (Querczts spp.) being the most 3 common species. Shrub, sapling and vine 6 density is high over much of the area pro- 13 viding a dense undercover. The elevation 24 Jan

ranges from 280 to 350 meters. 1 Lost on 28 October and found on 21 November. Trailing devices (Stickel, 1950) were used to study winter movements and to follow turtles to their hibernacula. Trailed turtles were recorded on 21 different days. Move- were checked daily with the path and dis- ments were common until 13 December after which no movements were recorded until 24 tance of movement recorded. ' In addition, depths and types of hibernacula were re- January. corded whenever the turtles burrowed into The relationship between temperature, the leaf litter and became inactive. precipitation and movements was examined. Maximum and minimum daily soil tem- Two trends were apparent. The first was peratures were recorded at a depth of 10 cm that movements were more common on (3.8 cm of leaf litter, 6.2 cm of soil) on an warmer days. IVhile only 29 of the 103 days east facing slope in the area of activity of (28%) had a maximum temperature of above two trailed turtles. Daily air and precipita- 16OC, 32 of the 43 movements (74%) oc- tion data were obtained from a U.S. Weather curred on these days. The other 11 move- Bureau station, 11.2 km from the study area. ments occurred on days in which the maxi- Trailing devices were attached to 11 turtles mum temperature ranged between 7 and between 10 and 21 October. Six of these 14OC. The second trend was that move- turtles were lost by 22 October so only five ments were closely related to rainfall during turtles were trailed throughout the complete December and January; nine of the ten period (until 31 January). movements recorded in these months oc- From 10 to 21 October, daily movements curred on the day of or following a rainfall of at least two, and usually all, of the trailed of 6.5 mm or more. Such a relationship was turtles occurred. After 22 October, the first not found in October and November as only day of no movements, the daily movements 15 of the 33 movements occurred on days of varied considerably. Table 1 shows the record or following a rainfall of any amount. This of movements for the five turtles trailed from indicates that rainfall may have a much 21 October through 31 January. During this greater influence on movements during the 103-day period, 43 individual movements colder part of the winter. The daily maxi- HERPETOLOGICAL NOTES

01 * I I I I I I I 2 1 4 I8 3 20 1 14 25 OCT. NOV. DOC. JAN.

OCT. N OV. DEC. JAN.

Fig. 1. Depths of hibernacula for eastern box turtles. A, Distance from leaf litter surface to carapace top; B, Distance from soil surface to base of hibernacula. Lines fitted by eye. mum temperature averaged 6.1°C lower for The types of hibernacula varied with the December and January as compared to 21 season. In late fall, the turtles sometimes October-30 November. burrowed under leaf litter in open sites, but Mihenever the turtles were not active, they more often chose places where leaf litter were burrowed under the leaf litter. Peri- had built up, such as next to fallen logs, odically, measurements were made of depths stumps or rocks. In colder weather, the tur- to which the turtles burrowed (Fig. 1). tles preferred stump holes; four of the five Hibernacula depths increased until mid- turtles spent 13 December-24 January in, December and leveled off at an average or next to, stump holes. These depressions depth of 15.5 cm (9.'i leaf litter, 5.8 soil). contained a thick mat of leaf litter and the The turtles usually shaped out a cavity in soil was mixed with rotting wood. the soil so that the top of the carapace was Previous studies have shown that winter even with the soil surface. This depth was movements are not uncommon for the box adequate to insulate the turtles from the turtle. Carpenter (1957) studied the hiber- coldest temperatures through 31 January. nation of the three-toed box turtle, Terra- The minimum recorded soil temperature at pene c. triunguis, in Oklahoma, and found 10.0 cm (3.8 leaf litter, 6.2 soil) was l.l°C. that turtles were often active during fall and This recording was taken within 7 m of two early winter. Cahn (1933) reported that 24 turtle hibernacula. The maximum depth eastern box turtles in an enclosed pen in reached by any turtle was 19.0 cm (12.7 leaf Illinois went into hibernation in late No- litter, 6.3 soil). vember after a three-week period of alter- 760 COPEIA, 1971, NO. 4 nating burrowing and active movement. He RADlOTELEnIETRIC OBSERVATIONS also noted that two turtles moved about the OF CARDIAC RATES IN THE ORNATE pen for one day in January. Allard (1948) BOX TURTLE.-A pulse-modulated radio reported finding turtles active during all transmitter, a single pulse triggered by each months of winter. QRS spike of the animal's electrocardiogram, Only scattered observations have been was used to monitor the cardiac activity of previously made on box turtle hibernacula. an adult male ornate box turtle, Terrapene Carpenter (1957) reported that the average ornata ornata, moving about in nature with hibernacula depth of the three-toed box tur- considerable freedom of movement. These tle was 13.5 cm (7.1 leaf litter, 6.4 soil). In observations extended from 26 August to 26 his study, 39% of the hibernacula were lo- September 1966. cated in decaying stump holes. hlinton (1944) The electrocardiogram signal was moni- reported that an eastern box turtle hiber- tored via silver wire electrodes introduced nated at a maximum depth of 12.7 cm during through small holes drilled in the carapace. one winter in Illinois. In Great Smoky This signal, after amplification, triggered a Mountains National Park, an eastern box pulse circuit which turned on the transmit- turtle was discovered in mid-winter hiber- ter, once for each beat of the heart. The nating under a brush pile with its carapace weight of the apparatus was about 35 g, or top even with the soil surface (Huheey and about 10% of the body weight. Stupka, 1967:46). As an example of the types of observations In conclusion, eastern box turtles select such a systei makes Fig. 1 shows areas with a thick mat of leaf litter, rotting the time course of the cardiac rate, in beats wood or brush for hibernacula sites. The per minute, during a morning period of depths and types of hibernacula are similar basking. The rate observations were begun to those of the three-toed box turtle. Winter from a vantage point out of sight of the turtle. An increasing cardiac rate suggested movements are more common on warmer that the animal was basking and this was days. Rainfall appears to be an important visually confirmed by unobtrusive observa- stimulus for movements during December tion. The turtle remained nearly motion- and January. less during.u the entire time indicated. with Appreciation is extended to James T. only an occasional head movement. At the Tanner for reviewing the manuscript. time indicated on the figure the turtle abruptly left the spot where he had remained for over an hour and moved into shade ALLARD,H. A. 1948. The eastern box turtle nearby. There followed a slight slowing of and its behavior. J. Tenn. Acad. Sci. 28:307- the heart, after a maximum rate of 48 beats 321. ver min had been reached. CAHN,A. R. 1933. Hibernation of the box ' Fig. 2 summarizes one month's observa. turtle. Copeia 1933(1):13-14. tions on the effect of temperature on cardiac CARPENTER,C. C. 1957. Hibernation, hibernacula and associated behavior of the three- rate. The temperature measurements repre- toed box turtle (Terrapene carolina triunguis). sent ambient air temperature at ground level Copeia 1957(4):278-282. in the immediate vicinity of the turtle. Ob- HUHEEY,J. E., AND A. STUPKA. 1967. Amphib- servations were included only in cases where ians and reptiles of Great Smoky Mountains National Park. Univ. of Term. Press, Knox- equilibrium conditions seemed to pertain ville. Tenn. (in the shade with the cardiac rate reason- MINTON.S. 1944. Introductions to the studv of ably constant over an interval of several reptiles of Indiana. Am. Midl. Nat. 32(2): minutes). Under these conditions it was as- 438477. sumed that the turtle's body temperature SHANKS,R. E., AND F. H. NORRIS.1950. Micro- climatic variation in a small valley in eastern would closely reflect that of the surrounding Tennessee. Ecology 31:532-539. air. STICKEL,L. F. 1950. Populations and home Data relating turtle cardiac rate and tem- range relations of the box turtle, Terrapene c. perature are meager, and that which does carolina (Linnaeus). Ecol. Monogr. 20:351- exist has been taken under laboratory, rather 378. than field, conditions. Akers and Damm RICHARDA. DOLBEER,Colorado Cooperative (1963) exposed Graptemys geographica and T/C7ildIifeResearch Unit, Colorado State Uni- Pseudemys scripta elegans to infrared heating versity, Fort Collins, Colorado 80521. lamps while temperatures were taken with