Memory Drives the Foraging Behavior of Large Wild Mammals

April 13, 2021
Roe Deer courtesy of Nathan Ranc

A recent study published in Proceedings of the National Academy of Sciences shows that the foraging decisions of roe deer are guided primarily by memory, and not sensory perception alone.

The cognitive processes underlying the foraging decisions of large mammals in nature are not well understood, in part because it has been difficult to disentangle the effects of sensory perception and memory on the animals’ movements. Nathan Ranc (Ph'D '20) and Professor Paul Moorcroft collaborated with Dr. Francesca Cagnacci and Dr. Federico Ossi at the Fondazione Edmund Mach, Italy, to examine this question by attaching GPS-based telemetry collars to 18 roe deer and tracking their movements during a food manipulation experiment.

More than 50 feeding sites, typically consisting of trays filled with corn, had been traditionally used by hunters throughout the study area in Trentino, Eastern Italian Alps. The authors placed wooden boards on top of the trays at popular feeding sites, restricting access to the corn for two weeks, but the food and associated sensory cues such as smell were still present. The deer spent only 5% of the time at these manipulated sites during the closure period, compared to 31% of the time during the prior two weeks. The findings support a memory-based mathematical model of foraging behavior, but not a perception-based model, which predicted no decrease in site visitation.

Roe deer foraging decisions were based on recent experience of food location and accessibility enabling them to adapt to sudden changes in resource availability. The model was able to accurately predict how roe deer respond to changes in the distribution of resources. According to the authors, understanding how animals respond to changing environmental conditions such as resource availability is critical to designing effective wildlife conservation and management strategies.