Escape dynamics of free-ranging desert kangaroo rats (Rodentia: Heteromyidae) evading rattlesnake strikes

Abstract

Many animals exhibit morphological specializations driven by the extreme selective pressure of predation, and understanding how such specializations shape escape behaviours can elucidate the evolutionary context of these morphologies. We examined the kinematics of the evasive leaps of desert kangaroo rats (Dipodomys deserti) during strikes from sidewinder rattlesnakes (Crotalus cerastes) to understand the potential importance of predator evasion in shaping bipedalism in desert rodents. We found that kangaroo rats escaping from snake strikes relied on rapid response times to initiate effective evasions. During jumps, their enlarged hindlimbs propelled vertical leaps that were multiple body lengths into the air, and these leaps were often accompanied by mid-air kicks and other manoeuvres that deterred snakes. Although we found high levels of variability in kinematic factors, all kangaroo rats that successfully evaded attacks escaped in a path away from the snake and thus did not have random/protean escape trajectories. In general, our findings support the idea that bipedalism, which has evolved independently in several desert rodent lineages, might be favoured because it allows for rapid and powerful vertical leaps that are crucial for avoiding ambush predators, such as vipers and owls.

Comparative analysis of Dipodomys species indicates that kangaroo rat hindlimb anatomy is adapted for rapid evasive leaping

“…These predators would therefore place little selective pressure on jump performance. However, when evading single‐strike ambush predators such as rattlesnakes and owls, they utilize impressive jump escapes (Freymiller et al, 2019; Higham et al, 2017; Webster, 1962; Whitford et al, 2019). Escaping from such predators requires a quick jump that rapidly moves the body out of the trajectory of the attack; if they are able to dodge the initial strike, the predator cannot immediately launch a fully coordinated second attack, thus giving the kangaroo rat time to escape (Kardong & Bels, 1998; Shifferman & Eilam, 2004).…”

“…In general, bipedality in rodents appears to have evolved as a means of enhancing predator evasion (McGowan & Collins, 2018), and kangaroo rats perform impressive, acrobatic leaps that aid in their escape from predators (Higham et al, 2017; Webster, 1962; Whitford et al, 2019). During these escapes, kangaroo rats rely on their large hindlimbs to jump up to a meter into the air with maximal velocities exceeding 4 m/s, which is equivalent to 27 body lengths per second (Freymiller et al, 2017, 2019). That said, it is not clear if kangaroo rats are morphologically adapted to optimize jump distance or acceleration.…”

How a Serpentine Tail Assists Agile Motions of Kangaroo Rats: A Dynamics and Control Approach

“…Therefore, the kangaroo rat is thought to be a great benchmark model to investigate the functions of a tail for bipedal locomotion. This idea recently started attracting attention and a series of research efforts were carried out, from both the biological side [31][32] and the robotic side [10,[33][34]. However, the existing efforts on the biological side mainly focus on data interpretation using statistical analysis, and the efforts on the robotic side mainly focus on using the pendulum tail abstraction.…”

Mechanisms for Mid-Air Reorientation Using Tail Rotation in Gliding Geckos

“…2013 ), and lizards (; Clemente and Wu 2018 ) use their tails to change body orientation while running over variable terrain. Tails are also used to change body orientation in mid-air by leaping ( Dunbar 1988 , 1994 ) or saltatory ( Freymiller et al. 2019 ) animals.…”