Herpetology Notes, volume 14: 749-753 (2021) (published online on 10 May 2021)

Predation by the wolfsnake aulicus (Linnaeus, 1758) on the house frenatus Duméril & Bibron, 1836 in Tsirang District, Kingdom of Bhutan

Jigme Tshelthrim Wangyal1,*, Pema Khandu2, and Gyeltshen Gyeltshen3

Wolfsnakes, Lycodon Fitzinger, 1826, are Hemidactylus frenatus Duméril & Bibron, 1836 is a known to prey upon rodents and frogs (Fritts, 1993), common house gecko that occurs throughout most of and they may even endanger the survival of bird tropical Asia eastwards into the western Pacific, with (Khamcha and Gale, 2020). However, their biggest introduced populations in parts of Africa, the Americas, impact as a predator is most likely on the broad variety and many islands of the Indian and Pacific Oceans of lizards they consume, including house , (Kraus, 2009). These moderate-sized geckos (maximum , and agamids (Fritts, 1993; Pauwels et al., 2005; snout-to-vent length 65 mm) were identified using Vogel et al., 2009; Zhang and Wang, 2014). Lycodon identification keys in Smith (1943), Vyas (2005), Giri aulicus (Linnaeus, 1758) in particular is known to feed and Bauer (2008), and Lajmi et al. (2016). In this article, on common house geckos (Daniel, 2002; Jackson and we report the observation of preying Fritts, 2004) and, consequently, it may frequently be upon Hemidactylus frenatus and provide a description seen in and around residential buildings where these of how the attack happened in a sequence of photos with prey species are most commonly encountered (Shroff, textual commentary. 2016). The second author’s neighbour sought his help to Behavioural information about L. aulicus is rather remove a found in her ceiling on 11 November scarce, although a few studies on some populations 2018 at Burichhu, Tsirang District, Bhutan (27.0823°N, and its distribution have been carried out (Ganesh and 90.0762°E, elevation 470 m). The atmospheric tempera- Vogel, 2018; Deshmuk et al., 2020; Ganesh et al., 2020). ture at the time was ca. 14°C while the room tempera- The species is chiefly nocturnal and known to be partly ture was slightly higher at ca. 17°C (NCHM, 2017). We arboreal, sometimes utilizing tall trees (Harrington et suspect that the usually nocturnal snake became active al., 2018), but is most frequently observed in crevices during the warm morning and took the opportunity en- or depressions, under objects, or moving near human ter the warmer, two-storied traditional Bhutanese house settlements. These are generally shy and alert , to hunt. Both prey availability and warmth could have but they may exhibit more aggressive behaviour attracted the snake, which scaled the building’s walls, than other wolfsnakes (Harris et al., 2010). Several as also reported by Ganesh et al. (2020). A common specimens encountered on the campus of the College wolfsnake (total length ca. 800 mm) was found on one of Natural Resources, Punakha, Bhutan, coiled up when of the ceiling joists, holding a common house gecko in provoked and tried to escape. Repeated attempts to bite its jaws (Fig. 1). The series of behaviours by the snake while being handled have been observed by the first associated with predation on the gecko during the fol- author. lowing several minutes were observed and are reported in detail as follows: The snake was first encountered strongly biting the central body of the gecko with two coils compressing 1 University of New England, Armidale, New South Wales 2350, . Present address: Jigme Khesar Strict Nature the anterior part of the body, likely making it difficult Reserve, Haa 15001, Bhutan. for the gecko to inflate its lungs to breathe (Fig. 1). 2 Wangbama Central School, Genekha, Thimphu, Bhutan. Upon detection of our presence the snake released 3 Mendrelgang Primary School, Tsirang, Bhutan. the gecko (presumably to allow it to react to the * Corresponding author. E-mail: [email protected] disturbance), which dropped to the floor of the home. © 2021 by Herpetology Notes. Open Access by CC BY-NC-ND 4.0. Unlike normal house gecko behaviour, the seriously 750 Jigme Tshelthrim Wangyal et al.

pursuing, subduing, and swallowing prey, to the best of our knowledge there has never been a pictorial report of an encounter between L. aulicus and H. frenatus with complete, pictorial documentation of the encounter. Beyond a simple predator-prey interaction, the detail of our photographs could be informative in terms of functional morphology, as the movement of the snake during swallowing and subsequent peristalsis can be seen. Lastly, with a rather small body of herpetological literature for Bhutan, we hope that publication of this observation may encourage others to make and report on similar encounters from the country.

Acknowledgements. First and foremost, we are grateful to Aaron Bauer (Villanova University, Pennsylvania, USA for providing a pre-peer review, confirming the identification of the gecko, providing technical input, and correcting our text. Our field colleagues who helped us and still support us in our research are also gratefully acknowledged. We are also thankful to Sonam Dorji, Chencho Bidha, and Sonam Tshering for their help in the field, and to Ap Tashi, the homeowner, and Nima Lepcha, the tenant, for granting permission to enter their properties to take photos and rescue the snake.

References

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Figure 3. The images in this panel show in detail the series of movements on the part of Lycodon aulicus as it subdues, constricts, and immobilizes (A–F) and swallows (G–L) a house gecko. Note the concertina-like peristaltic movement in the later images.

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Accepted by Lukas Hartmann