Unpredictable aggressive defense of the venomous snake, Crotalus ravus, towards predators and humans

This dataset shows data on the behavioral response of the Mexican pigmy rattlesnake Crotalus ravus to the approach of simulated predators (an overflying bird, an attacking bird, and a fox) and a human and its behavior towards a prey (mouse). All observed behaviors are included and consisted of escape, rattle, bite, freezing the body, lateral compression of the body, elevating the head, and hiding the head near or below its body. 21 snakes were tried in all tests. For each trial, the data shows behaviors presented, their frequency, the chronological order in which behaviors were displayed, and the distance from the predator or prey (i.e., the approach distance). When the snake escaped the flight distance is given. In cases of the behavioral responses body compression and rattle duration is also given. The first response is given with the reaction distance, also the first essential behavior shown is given. Essential behaviors are escape, rattle or bite, so called because these important behaviors may avoid or result in an ophidian accident.

Methods
Data was recorded on focal snakes during the approach of a potential predator or in the presence of a prey. Human trials took place in the field before capture, a human approached the snake at approximately 2 km/h. In the other predator trials, a stuffed fox and a silhouette of a bird approached the snake in a direct line from a distance of 300 cm, using pulleys. In the trial of the overflying bird the bird silhouette approached the snake in a horizontal line at a height of 3 m, whereas the attacking bird approached the snake in a dive with a 45º angle, starting at a height of 3 m at 3 m distance. In the trial with the prey, the snake was placed in a corner of an enclosure of 1.5 x 1.5 m and then a mouse was released in the opposite corner. Sample size is 21 snakes.