U.S. Department of Agriculture: Animal and Plant Health Inspection Service
United States Department of Agriculture Wildlife Services: Staff Publications
Document Type
Article
Date of this Version
September 2007
Abstract
Gopherus polyphemus has declined precipitously in range and numbers in Florida and recently was state-listed as a "threatened" species under the Florida Wildlife Code (Chap. 39, Florida Administrative Code). At ca. 1000 h on 27 July 2006, GK observed a 23 cm carapace length male G. polyphemus between the North- South railroad tracks on the eastern boundary of Savannas Preserve State Park (SPSP) in St. Lucie County, Florida (Fig. 1). The tortoise seemed uninjured, but was deceased. Eastern Box Turtles (Terrapene carolina) were recently shown to have great difficulty escaping railroad tracks, with overheating to critical levels likely to occur in 4.5-5 h (Kornilev et al. 2006. Herpetol. Rev. 37:145-148). Similarly, the most logical explanation for the Gopher Tortoise death would be entrapment between the tracks, followed by critical overheating and/or dehydration (high and average temperatures for the previous day had been ca 31°C and 28"C, respectively). Recent re-contouring of the railroad track right-of-way corridor with crushed rock had coincidentally created "ramps" (Fig. 2) increasing the feasibility for tortoises to scale the track rail to reach the interior portion of the tracks. Alternatively, access to the interior of the tracks could have been accomplished at the crossing intersection at nearby Walton Road, 186 m south of where the carcass was found, with the tortoise continuing to move along the tracks, instead of escaping by retracing its route. Turtle species with superior climbing abilities to G. polyphemus might be more able to escape entrapment between the 19 cm high rails (if they are of sufficient size). For example, Engeman (in press, J. Kansas Herpetol.) observed a 33 cm carapace-length Apalone spinifera climb a series of 14 stairs, each 18-19 cm high, indicating that such an individual might be able to escape the railroad tracks.
Comments
Published in Helpetological Review 38(3), 2007.