Random walk analysis of ranging patterns of sympatric langurs in a complex resource landscape

Abstract

The identification of random walk models to characterize the movement patterns of social groups of primates, and the behavioral processes that give rise to such movement patterns, remain open questions in movement ecology. Movement patterns characterized by a power-law tail with exponent between 1 and 3 (Lévy flight) occur when animals forage on scarce, randomly distributed resources. For primates and similar foragers with memory processes, movements resembling Lévy flights emerge when feeding trees (targets) are randomly distributed and the trunk size distribution of targets follows a power-law. We tested three competing random walk models to describe movement patterns of two langur species. We found a truncated power law to be the most suitable model. The power-law model was poorly supported by the data and hence we found no support for Lévy-flight-like behavior. Moreover, the spatial distribution of feeding trees and the probability distribution of feeding tree size differed from values suggested to result in Lévy-flight-like patterns. We identify intraspecific territoriality, foraging behavior, and the spatial and size distribution of food patches as plausible mechanisms that may have given rise to the observed movement patterns.

Evidence of Lévy walk foraging patterns in human hunter–gatherers

“…Although previous work provides conflicting evidence of the use of Lévy walks in nonhuman primates (2,4,(26)(27)(28)(29), our study presents the largest and most comprehensive dataset analyzed to date showing Lévy walk strategies in human foragers. While we have used model selection statistics to rule out alternative models for step length distributions in foraging bouts conforming to power laws and truncated power laws, it is possible that environmental features may drive these distributions.…”

Lévy walks

“…Several kinds of animals were tracked by this method: baboons (Schreier and Grove, 2014), spider monkeys (Ramos-Fernández et al, 2004), fallow deer (Focardi, Montanaro, and Pecchioli, 2009), jackals (Atkinson et al, 2002), reindeer (Marell, Ball, and Hofgaard, 2002), langurs (Vandercone et al, 2013), and bearded sakis (Shaffer, 2014).…”

Effect of temperature on activity budgets of free ranging Dusky Toque Macaques (<em>Macaca sinica aurifrons</em>): A case study from Peradeniya University premises, Sri Lanka

“…Only whole day follows were taken to the analysis and January was omitted due to low data collection. Each scan lasted for ≤3 minutes for every 10 minute interval (Vandercone et al, 2012). All age and sex classes were included in each scan, which comprised of many adults and sub-adult individuals (Vandercone et al, 2012).…”

“…Each scan lasted for ≤3 minutes for every 10 minute interval (Vandercone et al, 2012). All age and sex classes were included in each scan, which comprised of many adults and sub-adult individuals (Vandercone et al, 2012). Infant activities were not included because they usually stay tied up with their mother.…”