Autohaemorrhaging in a Bahamian pygmy boa, Tropidophis curtus barbouri

Abstract

S use a wide variety of antipredatory behaviours, including gaping, exuding musk, defecating, convolving, feigning death, and autohaemorrhaging (Greene, 1994). Autohaemorrhaging, or the deliberate ejection of blood, in snakes occurs via either the cloaca or the orifices of the head (i.e. nares, mouth and orbits). In reptiles, autohaemorrhaging is already known from a few species of snakes in the genera Heterodon, Nerodia, Rhinocheilus, Natrix, Zamenis, and Tropidophis as well as in the lizard genus Phrynosoma (Smith et al., 1993; Greene, 1994; Sherbrooke & Middendorf, 2001; Gregory et al., 2007; Iiftime & Iftime, 2014). In the genus Tropidophis specifically, which is also unusual in that some species are known to be able to change colour, cephalic autohaemorrhaging has so far been recorded in 13 out of 32 species (Smith et al., 1993; Greene, 1994; Torrest et al., 2013; Iturriaga, 2014). In a brief report, Hecht et al. (1955) were the first to describe autohaemorrhaging in Tropidophis curtus curtus (formerly known as Tropidophis pardalis). Here we offer greater detail of cephalic autohaemorrhaging in a different sub-species, the Bahamian pygmy boa (Tropidophis curtus barbouri), including access to the first-ever published video footage of this behaviour in any snake species (YouTube, 2019). Knowing that T. c. barbouri is found on several islands across the Bahamian archipelago where it inhabits mesic, wooded areas (Henderson & Powell 2009; Powell & Henderson, 2012), we conducted an expedition and found an adult individual under a small rock in the Leon Levy Plant Preserve on Eleuthera, The Bahamas, on 20 October 2019 at 16:25 h. The snout vent length of the snake was 352 mm and tail length 42 mm, dorsally it was coloured beige-brown and ventrally the tail was yellow (Fig. 1). Immediately after capture, it defecated and discharged musk. When gentle pressure was applied to the head, the eyes almost immediately filled with blood and a drop was exuded from the mouth (Fig. 2). After 2.4 sec of pressure both eyes began to fill with blood (starting from the postocular side) and were fully flooded within 0.7 sec. Blood started to exude from the mouth 0.8 sec after the eyes were fully filled and only two drops were expelled. After 4.4 sec the blood was re-absorbed from the postocular side and the eyes were completely clear within 1.6 sec. Overall, it took 6.7 sec from the start of the cephalic autohaemorrhaging to the full clearing of the eyes. After autohaemorrhaging, the snake appeared to be in full health and was returned to the location in which it was found. The Herpetological Bulletin 150, 2019: 39-40