The behaviour and evolution of cache protection and pilferage

Scatter hoarding by the Central American agouti: a test of optimal cache spacing theory

“…Thus, hoarding seeds in low-food areas, everything else being equal, came with a higher risk of cache loss to food competitors. This implies that food scarcity requires greater investments of scatter hoarders in strategies to minimize pilferage risk (Dally et al 2006). Second, we found that agoutis cached Astrocaryum palm seeds further away and into lower densities where ambient food availability was lower and hence cache pilferage risk higher.…”

“…These results are strong evidence for the dependence of spatial patterns of cache pilferage and scatter hoarding on the economic value of food (Jansen et al 2004). They add to previous studies which showed that scatter hoarders varied their caching strategy in response to the presence of food competitors (reviewed in Dally et al 2006;Hopewell et al 2008).…”

“…An important problem for hoarders is the risk of cache robbery by food competitors, which can imperil the animal's reserves and thereby lower its survival and future reproductive capacity (Wauters et al 1995). So-called scatter hoarders deal with this risk by spreading their reserves over numerous caches that are spaced out into such a low density that they cannot be efficiently exploited by cache robbers (Dally et al 2006). Several studies have shown that cache robbery is indeed density dependent (e.g.…”

“…Stapanian & Smith 1978, 1984Waite 1988;Daly et al 1992;Tamura et al 1999;Male & Smulders 2007a; but see Kraus 1983;Jensen 1985;Henry 1986;Van Horik & Burns 2007). Stapanian & Smith (1984) proposed that scatter-hoarding animals must space out their caches to a degree that optimally balances the benefits of reducing cache robbery risk and the costs of carrying food items to caches: 'optimal cache spacing' (Stapanian & Smith 1978;Clarkson et al 1986;Dally et al 2006). Empirical tests of optimal cache spacing theory (henceforth, OCST) have yielded mixed results; whether cache robbery is indeed density dependent and whether scatter hoarders actually cache seeds in an optimal density have remained controversial.…”

Scatter hoarding and cache pilferage by superior competitors: an experiment with wild boar, Sus scrofa

“…Larders are relatively easy to create and recover, yet usually require active defence against other animals, which costs time and energy, involves risk of injury and is successful only if the hoarder is superior to its competitors (Clarkson et al, 1986;Dally, Clayton, & Emery, 2006;Daly, Jacobs, Wilson, & Behrends, 1992;Vander Wall, 1990). Moreover, larders emit stronger odours; hence, for competitors, larders may be easier to detect by olfaction than small caches.…”