Biphasic tentacle strike kinematics in predatory cuttlefish

Cuttlefish extend soft tentacles to capture evasive prey. High speed imaging of tentacle prey capture in two cuttlefish species reveals kinematically discrete, biphasic tentacle extension. A prolonged reach phase, often extending distances greater than their mantle length, is followed by a close-range, rapid attack phase. Reach phase duration is orders of magnitude longer and more variable than attack phase duration. Attack phase speeds vary minimally, such that attack duration is determined by prey distance. Biphasic strikes integrate slow and stealthy prey tracking during the variable reach phase followed by a less variable, close-range, fast attack phase. The attack phase is so brief that it is likely shorter than response latencies of many prey, but is so brief that it may be limited to open loop control. Comparisons among animals using soft, extensible predatory mechanisms reveal that cuttlefish biphasic tentacle strikes rival both distances and speeds of iconic vertebrate ballistic tongues.