title: Scaling laws of ambush predator 'waiting' behaviour are tuned to a common ecology.
abstract: The decisions animals make about how long to wait between activities can determine the success of diverse behaviours such as foraging, group formation or risk avoidance. Remarkably, for diverse animal species, including humans, spontaneous patterns of waiting times show random 'burstiness' that appears scale-invariant across a broad set of scales. However, a general theory linking this phenomenon across the animal kingdom currently lacks an ecological basis. Here, we demonstrate from tracking the activities of 15 sympatric predator species (cephalopods, sharks, skates and teleosts) under natural and controlled conditions that bursty waiting times are an intrinsic spontaneous behaviour well approximated by heavy-tailed (power-law) models over data ranges up to four orders of magnitude. Scaling exponents quantifying ratios of frequent short to rare very long waits are species-specific, being determined by traits such as foraging mode (active versus ambush predation), body size and prey preference. A stochastic-deterministic decision model reproduced the empirical waiting time scaling and species-specific exponents, indicating that apparently complex scaling can emerge from simple decisions. Results indicate temporal power-law scaling is a behavioural 'rule of thumb' that is tuned to species' ecological traits, implying a common pattern may have naturally evolved that optimizes move-wait decisions in less predictable natural environments.
authors.affiliation: Marine Biological Association of the United Kingdom, The Laboratory, , Citadel Hill, Plymouth PL1 2PB, UK, European Institute of Marine Studies (IUEM), University of Western Britanny, , Place Nicolas Copernic 29280, Plouzané, France, School of Computing and Mathematics, University of Plymouth, , Drake Circus, Plymouth PL4 8AA, UK, Rothamsted Research, , Harpenden AL5 2JQ, UK, Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, , Waterfront Campus, Southampton SO14 3ZH, UK, Centre for Biological Sciences, University of Southampton, , Building 85, Highfield Campus, Southampton SO17 1BJ, UK.
authors.forename: Victoria J
authors.initials: VJ
authors.lastname: Wearmouth
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: McHugh
authors.forename: Nicolas E
authors.initials: NE
authors.lastname: Humphries
authors.forename: Aurore
authors.initials: A
authors.lastname: Naegelen
authors.forename: Mohammed Z
authors.initials: MZ
authors.lastname: Ahmed
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Southall
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Reynolds
authors.forename: David W
authors.initials: DW
authors.lastname: Sims
mesh_terms: D000818:Animals; D001267:Atlantic Ocean; D049830:Cephalopoda; D017753:Ecosystem; D005247:Feeding Behavior; D005399:Fishes; D008954:Models, Biological; D009043:Motor Activity; D011235:Predatory Behavior; D011336:Probability
keywords: foraging strategy; human dynamics; intermittence; movement ecology; random walk; search