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Predation on a Northern Long-eared Myotis by a Gray Rat Snake
Brian D. Carver and Anabel E. Lereculeur

Southeastern Naturalist, Volume 12, Issue 4 (2013): N6–N8

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2013 Southeastern Naturalist Notes Vol. 12, No. 4 N6 B.D. Carver and A.E. Lereculeur Predation on a Northern Long-eared Myotis by a Gray Rat Snake Brian D. Carver1,* and Anabel E. Lereculeur1 Abstract - A number of species are known to be predators of bats. In North America, the greatest number of bat predation records is by snakes. To date, no animals have been reported preying on Myotis septentrionalis (Northern Long-eared Bat). We report the predation of a Northern Long-eared Bat by Pantherophis spiloides (Gray Rat Snake) in Tennessee. Myotis septentrionalis Trouessart (Northern Long-eared Bat) are small bats (5–8 g) found in eastern and northern North America. Like several other eastern Myotis bats, Northern Long-eared Bats roost under exfoliating tree bark or in tree cavities during summer and hibernate in caves during winter (Caceres and Barclay 2000, Chapman 2007). We initiated a project in May 2012 to evaluate roost selection by Northern Long-eared Bats on the Cumberland Plateau in Tennessee. On 18 May 2012, a pregnant female Northern Long-eared Bat was captured in a mist net set over a forest road in Catoosa Wildlife Management Area in Morgan County, TN. We trimmed the fur between the scapulae, affixed a 0.35-g radio-transmitter (model LB-2N, Holohil Systems Ltd., Carp, ON, Canada) with surgical cement (Perma-Type, Plainville, CT), and then we affixed a 2.9–mm lipped aluminum-alloy band (Porzana Ltd., East Sussex, UK) to the left forearm. The bat was released at the site of capture. 1Department of Biology, Box 5063, Tennessee Technological University, Cookeville, TN 38505. *Corresponding author - bcarver@tntech.edu. Notes of the Southeastern Naturalist, Issue 12/4, 2013 Figure 1. Gray Rat Snake that consumed a radio-transmittered Northern Long-eared Bat at Catoosa Wildlife Management Area, Morgan County, TN. Note the distended abdomen indicating the presence of the recently (less than 24 h) consumed bat. N7 2013 Southeastern Naturalist Notes Vol. 12, No. 4 B.D. Carver and A.E. Lereculeur On 19 May 2012, we found the bat in a live Quercus alba L. (White Oak) tree located 150 m from the site of capture. On 20 May 2012, the signal emanated from a 1-mtall Pinus sp. (pine) snag 460 m west of the previous roost and 410 m west of the site of capture. The pine snag was too short for standard diameter-at-breast-height (dbh) measurement, but if the trunk were intact it would have had a dbh of approximately 30 cm. Approximately 60 percent of the bark remained. Visual inspection of the roost structure revealed a Pantherophis spiloides Duméril, Bilbron, and Duméril (Gray Rat Snake) under the bark, and radio-telemetry led us to suspect that the snake had consumed the bat. We captured and examined the snake which was 50 cm in snout–vent length (SVL), and had an obvious distension of the abdominal wall from a recent meal (Fig. 1). Radiotelemetry was used to confirm that the snake had indeed consumed the bat. Because two taller, better-candidate roost trees were located less than 10 m from the pine snag, it is possible that the bat was roosting in one of the nearby trees when it was consumed by the snake, which then moved to the pine snag to digest the meal. However, during this study, we found six roosts where the bats were observed under loose bark or in a cavity located 1 m or less from the forest floor, demonstrating that Northern Long-eared bats roost in short snags. The exact location of the bat immediately prior to its discovery by the snake cannot be known, but consumption of large meals relative to body size are generally assumed to impair locomotion in snakes (Blouin-Demers and Weatherhead 2001), making it more likely that the predation event took place very near to the site where the snake was discovered. To our knowledge, this event represents the first published predation account of a Northern Long-eared Bat. Many species of snakes have been documented to prey on bats, including a number of bat species that, like Northern Long-eared Bats, roost under exfoliating bark (Sparks et al. 2000). The Gray Rat Snake was at one time considered to be a subspecies of the Black Rat Snake (formerly Elaphe obsoleta [Say]). The Black Rat Snake, and presumably the Gray Rat Snake in at least some instances, has been documented as preying on 8 species of bats, including Myotis lucifugus Le Conte (Little Brown Bat) and M. sodalis Miller and Allen (Indiana Bat), which are both very similar in size and roosting ecology to the Northern Long-eared Bat (Sparks et al. 2000). Wilson (1997) indicated that snakes may capture bats out of the air as they exit from their roosts. However, in the current instance this seems unlikely given that the snake was located at a site far distant from the roost used by the bat the previous night. It is more likely that the snake encountered the bat in its newly-selected day roost and was able to capture and consume it at that location. The late state of pregnancy of the bat in question may have increased the likelihood of the bat’s capture because it may have been less mobile than a post-parturient bat. The fact that the bat was nearly ready to give birth is supported by the capture on the same night (18 May 2012) of a lactating, post-parturient Northern Longeared Bat, as well as by the large distended abdomen of the bat in question. Acknowledgments. Funding for field travel and technician support was provided by a US Fish and Wildlife Service Section 6 Habitat Conservation Planning Assistance Grant administered by The Nature Conservancy and Tennessee Wildlife Resources Agency (TWRA). Additional funding was provided by TWRA and the Department of Biology and the Center for the Management, Utilization, and Protection of Water Resources at Tennessee Technological University. Field assistance was provided by Aubree Johnson, Caitlin Sebok, and Sarah Vogel. We thank Hayden Mattingly for reviewing the manuscript. Special thanks to Chris Simpson and Dustin Thames for logistical support at Catoosa Wildlife Management Area. 2013 Southeastern Naturalist Notes Vol. 12, No. 4 N8 B.D. Carver and A.E. Lereculeur Literature Cited Blouin-Demers, G., and P.J. Weatherhead. 2001. An experimental test of the link between foraging, habitat selection, and thermoregulation in Black Rat Snakes, Elaphe obsoleta obsoleta. Journal of Animal Ecology 70:1006–1013. Caceres, M.C., and R.M.R. Barclay. 2000. Myotis septentrionalis. Mammalian Species 634:1–4. Chapman, B.R. 2007. Northern Long-Eared Myotis. Pp. 199–204, In M.K. Trani, W.M. Ford, and B.R. Chapman (Eds.). The Land Manager’s Guide to Mammals of the South. The Nature Conservancy, Southeastern Region, Durham, NC. 546 pp. Sparks, D.W., K.J. Roberts, and C. Jones. 2000. Vertebrate predators on bats in North America north of Mexico. Pp. 229–241, In J.R. Choate (Ed.). Reflections of a Naturalist: Papers Honoring Professor Eugene D. Flaherty. Fort Hays Studies, Special Issue 1, Hays, KS. 241 pp. Wilson, D.E. 1997. Bats in Question. Smithsonian Institution Pre ss, Washington, DC. 168 pp.