Phrynosoma cornutum (Harlan, 1825) is a semi-arid dwelling lizard that is distributed throughout the south-central United States and north-eastern Mexico. This species, like many of the members of the Phrynosoma genera, display unique defensive behaviours such as blood-squirting to avoid capture by predators (Sherbrooke, 2003). Phrynosoma cornutum readily exhibits blood-squirting in response to canid attacks (Middendorf and Sherbrooke, 1992), and also have been documented to display this defensive behaviour during attacks from other mammalian predators (Sherbrooke et al., 2012). Mook et al. (2017) reported blood-squirting caused by a Speckled Kingsnake (Lampropeltis holbrooki; Stejneger, 1902), and on rare occasions hand-capture from humans can elicit this response (Sherbrooke and Middendorf, 2001). However, these rare occurrences are poorly understood (Lambert and Ferguson, 1985; Sherbrooke and Middendorf, 2001).