Scatter hoarding squirrels put ‘one egg in each basket’, necessitating three decision phases: assess and invest (measure and allocate cache effort to the item), manage the cache field (optimizing distribution to decrease cache raiding) and retrieval (and raiding) decisions. Squirrels show a remarkable degree of heuristic precision during the assessment and investment stage, even organizing their caches in a way that may enhance later recall of their locations.
Robin AN, Jacobs LF (2022) The socioeconomics of food hoarding in wild squirrels. Curr Opin Behav Sci 45:101139. https://doi.org/10.1016/j.cobeha.2022.101139 PDF
Delgado MM, Jacobs LF (2017) Caching for where and what: evidence for a mnemonic strategy in a scatter-hoarder. Roy Soc Open Sci 4:170958–6. https://doi.org/10.1098/rsos.170958 PDF
Delgado MM, Nicholas M, Petrie DJ, Jacobs LF (2014) Fox squirrels match food assessment and cache effort to value and scarcity. Plos One 9:e92892. https://doi.org/10.1371/journal.pone.0092892 PDF
Waisman AS, Lucas CG, Griffiths TL, Jacobs LF (2011) A Bayesian model of navigation in squirrels. In: Proceedings of the 33th Annual Meeting of the Cognitive Science Society, CogSci 2011. Boston, MA, pp 1274–1279. PDF
Preston SD, Jacobs LF (2009) Mechanisms of cache decision making in fox squirrels (Sciurus niger). J Mammal 90:787–795. https://doi.org/10.1644/08-mamm-a-254.1 PDF
Waisman AS, Jacobs LF (2008) Flexibility of cue use in the fox squirrel (Sciurus niger). Anim Cogn 11:625–636. https://doi.org/10.1007/s10071-008-0152-5 PDF
Gibbs SEB, Lea SEG, Jacobs LF (2007) Flexible use of spatial cues in the southern flying squirrel (Glaucomys volans). Anim Cogn 10:203–209. https://doi.org/10.1007/s10071-006-0059-y PDF
Jacobs LF, Liman ER (1991) Grey squirrels remember the locations of buried nuts. Anim Behav 41:103–110. https://doi.org/10.1016/s0003-3472(05)80506-8 PDF
Mission: find the nut.
It takes a village to study squirrels
Over 100 dedicated undergraduates, many of whom have gone on to graduate programs in animal cognition, animal behavior, vet school and even law school, have assisted our studies of squirrel behavior on the Berkeley campus.
Dr. Mikel Delgado
Mikel and a participant test out a new cognitive choice apparatus for a BBC film crew.
How to frustrate a squirrel
After eating a walnut reward for opening the puzzle box, squirrels respond with different tail signals if next time they find it locked, empty or baited with a low value piece of corn.
Delgado MM, Jacobs LF (2016) Inaccessibility of reinforcement increases persistence and signaling behavior in the fox squirrel (Sciurus niger). J Comp Psychol 130:128–137. https://doi.org/10.1037/com0000021 PDF
Currently completing her Ph.D. research on the behavior of native tree squirrels in the Department of Ecology and Evolutionary Biology at UCLA.
Berkeley can make you a little nutty
Molly Nicholas later became a brilliant computer scientist but it all began with squirrels…