Diurnal observation of a Malayan Krait Bungarus candidus (Reptilia: Elapidae) feeding inside a building in Thailand

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Diurnal observation of a Malayan Krait
The observation took place on Suranaree University of Technology (SUT) campus in Nakhon Ratchasima, Thailand (Image 1). The campus is ideal for supporting snakes in many green refugia, with 26 forest fragments on the SUT property ranging from 0.45-1.5 ha making it a good study area for assessing human-snake interactions. The university grounds are comprised of a variety of human-modified lands interspersed with degraded secondary dipterocarp forest fragments. Many of the larger buildings at the university contain open-roofed J TT garden areas at the center of their structures. These "green" atriums only measure about 200m 2 , however, they typically contain an assortment of flora as well as small, semi-permanent water features, thus providing suitable habitat for a variety of fauna.
In conjunction with an ongoing investigation of B. candidus movement at SUT, we offer a free snakeremoval and relocation service for "nuisance snakes" found in campus households. As a result, each year since our project began in late 2017 we have been notified about approximately 100 snakes that residents have encountered among their homes, gardens, or university buildings. We have documented a total of 17 snake species which came into contact with humans within our study site through these notifications. Those most frequently removed from buildings include the harmless Chrysopelea ornata, Oligodon fasciolatus, Ptyas mucosa, Ptyas korros, Lycodon capucinus, Coelognathus radiata, and Python bivittatus, and the highly venomous Naja siamensis, and Bungarus candidus. Non-target species are relocated to the nearest suitable habitat upon capture, while B. candidus are taken to the laboratory for morphometric data collection, including measuring the weight, snout-vent length (SVL), and tail length (TL), before being released. All rescued snakes are typically released within 100m from the capture location (well within the home range of most species).
At 07.05h on 08 January 2019, campus security contacted our team after a custodian staff member discovered two snakes interacting inside a large laboratory building. We arrived on scene at 07.15h to observe an adult female B. candidus (mass = 216.7g, SVL = 91.2cm, TL = 12.7cm) swallowing a small Golden Tree Snake Chrysopelea ornata (Shaw, 1802), in the hallway adjacent to the building's garden atrium (14.877°, 102.018°; Image 2). We documented the event from a distance of approximately 10m to avoid disrupting the animal's behavior. At the initial time of discovery the B. candidus had just begun to swallow the C. ornata head-first. By the time we arrived, the B. candidus had nearly completed ingestion of the C. ornata, which was unresponsive. The B. candidus pulled the prey item further down its esophagus with a series of corresponding side-to-side head and jaw movements, J TT as is typical feeding behavior in snakes. The prey item was no longer visible at 07.20h, approximately 40min after sunrise. Thereafter, we captured the snake and housed it within a plastic box so it could digest the prey item prior to taking morphological measurements and adding the individual to our ongoing B. candidus spatial ecology study. The B. candidus regurgitated the partially digested C. ornata approximately 24 hours post-ingestion (TL = 22cm).
This observation confirms that B. candidus forages for prey around and within buildings. The prey species, C. ornata, is known to commonly venture inside human habitations to feed on geckos which congregate there (Pauwels et al. 2003). Likewise, B. candidus may also be attracted to human settlements in order to take advantage of potential prey. This possibly increases the potential for snake-human encounters with the risk of life-threatening snakebites, and intentional and unintentional killings of snakes by humans (Ahsan & Rahman 2017; Knierim et al. 2017; Meek 2012). We suggest further investigation into the kraits' use of human settlements, including habitat selection, movement ecology, and human responses to snakes.
We provide evidence that B. candidus will occasionally remain active shortly after sunrise when engaged in feeding behavior, as this individual did not begin ingestion of the C. ornata until approximately 25min after sunrise. As characteristically nocturnal and highly cryptic snakes, kraits are generally at less risk of being detected by humans than are diurnal snake species (Viravan et al. 1992 www.threatenedtaxa.org The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.