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Herpetology Notes, volume 11: 585-587 (2018) (published online on 29 July 2018)

First record of male combat in the Elongated elongata (Blyth, 1853) from north-eastern Thailand

Matthew Ward1,*, Flora Ihlow2,3, Bartosz Nadolski1, Matthew S.Crane1, Tyler Knierim1, Taksin Artchawakom4 and Colin T. Strine1

Combat rituals are essential for many to The Indotestudo elongata (Blyth, select mates or defend resources particularly during the 1853) is a medium-sized tortoise reaching a straight breeding season (e.g., Cox et al., 2007). In Southeast carapace length of up to 36 cm and a body weight of Asia, there are numerous examples of reptilian taxa that up to 4 kg, with males growing larger than females exhibit intrasexual combat, including monitor lizards (Ihlow et al., 2016 and references therein). The species’ (Varanus spp.) (Early et al., 2002) and snakes (Shine, geographic range stretches across much of Southeast 1978) such as the Malayan pit viper (Calloselasma Asia including Cambodia, Laos, Myanmar, Thailand, rhodostoma) (Strine et al., 2015). Male combat has , and portions of Northwest India and Southern been shown to not only solidify territorial boundaries, China (Ihlow et al., 2016). The ecology and behaviour of but also to increase the mating success of larger males I. elongata is poorly understood, and only a few studies by favouring larger body sizes (Berry and Shine, 1980; focusing on in situ observations exist (Ihlow et al., 2016 Fitch, 1981; Schuett, 1997). Males of many and references therein). Herein we report on our field species are evolutionarily inclined to grow larger in size observation of combat between two male I. elongata than females in to dominate conspecifics during made at the Sakaerat Biosphere Reserve, located in combat and therefore father more offspring, even in Nakhon Ratchasima Province, Thailand (14.4933°N, systems where multiple paternities are possible (Blouin- 101.9219°E, WGS1984, 470 m asl). The reserve Demers et al., 2005; Chelliah and Sukumar, 2013). measures approximately 82 km2 and is covered by a Within some tortoise clades, males perform aggressive mosaic of dry evergreen forest, dry dipterocarp forest, competition in an attempt to occupy territories and and fragmented bamboo forest. Within the Sakaerat the associated harems of females during the breeding Biosphere Reserve, I. elongata appears to occur in season (see Berry and Shine, 1980 and references high densities, as the home ranges of the radio-tracked therein; Willemsen and Hailey, 2003; Malfi et al., 2011). individuals overlap up to 40% with conspecifics. Thus, However, males often remain passive towards male encounters between individuals may occur on a daily conspecifics outside of the breeding season (Willemsen basis, particularly during the rainy season between May and Hailey, 2003; Malfi et al., 2011). and October, which is the main activity and breeding period of the species (Ihlow et al., 2016 and references therein). On the 15th of May 2014, we observed and recorded

1 Department of Biology, Suranaree University of Technology, approximately one minute of video footage of two Nakhon Ratchasima, 30000, Thailand male I. elongata engaged in combat. The individual’s 2 Herpetology Section, Zoologisches Forschungsmuseum sexes were confirmed in the field based on their Alexander Koenig, Adenauerallee 160, 53113, Bonn, morphology. Both specimens exhibited a reddish-pink Germany hue surrounding the eyes and nostrils, which individuals 3 Museum of Zoology, Senckenberg, A. B. Meyer Building, of both sexes develop during the mating season (Ihlow Königsbrücker Landstraße 159, 01109 Dresden, Germany. et al., 2016 and references therein). The , one 4 Population and Community Development Association, 6 Sukhumvit soi 12, Klong Toey, Bangkok, 10110, Thailand. of which was roughly 20% larger than the other, were * Corresponding author. E-mail: engaged in combat on top of a flat, protruding rock [email protected] (approx. 2 m x 2 m in size) adjacent to a fallen tree trunk. 586 Matthew Ward et al.

Figure 1. Male combat in Indotestudo elongata with A) biting the anterior carapace rim; B) carapace ‘butting’; C) head retraction; and D) biting the opponent’s front limbs. Photos by Bartosz Nadolski.

Our observation occurred within dry dipterocarp forest, a higher rate of butting. However, the larger male about 10 m from an ecotone, separating the dipterocarp eventually took control, with an increasing intensity of forest from neighbouring bamboo forests. butting, forcing the smaller male backwards against the We were alerted by the sound of the competitors’ fallen tree trunk. Later, the larger male clearly showed carapaces crashing together, so the combat had begun at a higher frequency of attacks, eventually forcing the an unknown period of time prior to our arrival. Neither smaller male to retreat backwards toward the bamboo individual ceased combat nor was any other behavioural forest. The larger individual pursued and attacked the change in response to our approach observed. Therefore smaller male throughout its retreat. During the pursuit, we were able to observe and record the remainder of the another I. elongata, of unknown sex, appeared at the event. The males confronted each other head to head, scene. It did not engage in the combat, but followed the loudly butting their anterior carapace rims against the opponents as they vacated the area moving through the protruding front of the opponents’ carapace, utilizing dipterocarp forest and into the ecotone for at least 30 m all four feet for propulsion (Fig. 1). Each male would before all three were lost from sight. occasionally take backward steps to gain momentum, Although males of this species are not considered before darting forward to butt the opponents’ carapace. particularly aggressive, this behaviour has been The tortoises withdrew their heads into the carapace observed and reported for males and young tortoises before making impact. Opponents interrupted butting of undetermined sex in captivity (see Spencer, 1987; and bit each other’s front legs leaving characteristic McCormick, 1992; Senneke, 2000; Eberling, 2001) injuries (Fig. 2). When the defending individual as well as from individuals living in the semi-natural retracted its foot, the offensive tortoise started biting conditions of wildlife rescue centres in Vietnam ( the defending tortoise’s carapace. At first, the smaller Conservation Center) and Cambodia (Angkor Centre male appeared to fight with higher intensity, showing for Conservation of Biodiversity) (Ihlow pers. obs.). First record of male combat in the Elongated Tortoise from Thailand 587

Cox, R. M., Butler, M. A., John-Alder, H. B. (2007): The evolution of sexual size dimorphism in . In: Sex, size and gender roles: evolutionary studies of sexual size dimorphism, p. 38-49. Fairbairn, D.J., Blanckenhorn, W.U, Székely, T. Ed. Oxford, UK, Oxford University Press. Deepak, V., Ramesh, M., Bhupathy, S., Vasudevan, K. (2011): Indotestudo travancorica (Boulenger 1907)–. Conservation Biology of Freshwater and Tortoises, 1: 1-6. Earley, R.L., Attum, O., Eason, P. (2002): Varanid combat: perspectives from game theory. Amphibia-Reptilia, 23: 469- 485. Eberling, G. (2001): Haltung und Nachzucht von Indotestudo Figure 2. Characteristic biting injuries on the right front elongata (Blyth, 1853). Draco 2: 61-72. limb of an Indotestudo elongata male from Preah Vihear Fitch, H.S. (1981): Sexual size differences in reptiles. University of Cambodia. Photo by Flora Ihlow. Kansas, Museum of Natural History, Miscellaneous Publication, 70: 1-72. Ihlow, F., Dawson, J., Hartmann, T., Som, S. (2016): Indotestudo elongata (Blyth 1854) – Elongated Tortoise, Yellow-headed However, male to male combat in this species has not Tortoise, Yellow Tortoise. In: Rhodin, A.G.J., Pritchard, P.C.H., yet been documented in situ prior to our observation. van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater The observed male to male combat is very similar to Turtles and Tortoises, Chelonian Research Monographs, 5: 096 the species courtship behaviour (Ihlow et al., 2016 and 1-14 references therein) and identical to combat in other Kaddour, K.B., Slimani, T., Bonnet, X., Lagarde, F. (2008): Sexual species, such as the closely related Travancore Tortoise dimorphism in the : A Test of the Body Shape Indotestudo travancorica (Ramesh, 2008; Deepak et al., Hypothesis. Chelonian Conservation and Biology, 7: 21-27. 2011) and the European tortoises of the McCormick, B. (1992): The elongated tortoise. Indotestudo elongata. Tortuga Gazette, 28: 1-3. (Willemsen and Hailey, 2003; Kaddour et al., 2008). Malfi, A., Wakamatsu, K., Roulin, A. (2011): Melanin-based This first in situ observation of male to male combat colouration predicts aggressiveness and boldness in captive in I. elongata is valuable for future conservation work eastern Hermanns Tortoises. Behaviour, 81: 859-863. as well as the captive management of this endangered Ramesh, M. (2008): Relative abundance and morphometrics of tortoise species. the Travancore tortoise, Indotestudo travancorica, in the Indira Gandhi Wildlife Sanctuary, southern , India. Acknowledgments. We would like to express our appreciation to Chelonian Conservation and Biology, 7: 108-113. the National Geographic Conservation Fund, the British Chelonia Schuett, G. (1997): Body size and agonistic experience affect Group, Gurit Ltd, Craghoppers, and Perdix Wildlife Supplies dominance and mating success in male copperheads. Animal for their financial support and the equipment they provided. We Behaviour, 54: 213-224. are also grateful to the Sakaerat Environmental Research Station Senneke, D. (2000): Keeping and breeding Indotestudo elongata for accommodating herpetological research. Additionally, our the Elongated Tortoise. Tortoise Trust Newsletter. 15: 3-4. many thanks go to Suranaree University of Technology for the www.chelonia.org/articles/elongatacare.htm. opportunity to present our observations. Finally, we would like Shine, R. (1978): Sexual size dimorphism and male combat in to acknowledge the assistance of the many station researchers, snakes. Oecologia, 33: 269-277. volunteers, and staff who recorded the locations, made Spencer, B. (1988): The elongated tortoise and its management observations, and captured tortoises for our ongoing research. at the Minnesota Zoo. Bulletin of the Chicago Herpetological Society, 23: 37-40. Strine, C.T., Barnes, C., Silva, I., Nadolski, B., Artchawakom, T., References Hill, J., Suwanaree, P. (2015): First Record of Male Combat in Berry, J.F., Shine, R. (1980): Sexual size dimorphism and sexual a wild Malayan Pit Viper (Calloselasma rhodostoma). Asian selection in turtles (Order Testudines). Oecologia, 44: 185-191. Herpetological Research, 6: 237-239. Blouin-Demers, G., Gibbs, H.L., Weatherhead, P.J. (2005): Willemsen, R., Hailey, A. (2003): Sexual dimorphism of body size Genetic evidence for sexual selection in Black Ratsnakes, and shell shape in European tortoises. Journal of Zoology, 260: Elaphe obsoleta. Animal Behaviour 69: 225-234. 353-365. Chelliah, K., Sukumar, R. (2013): The role of tusks, musth and body size in male–male competition among Asian Elephants, Accepted by Eric Munscher Elephas maximus. Animal Behaviour, 86: 1207-1214.