This site aims to provide information on the behavior of food caching, focusing mainly on food caching by pikas, but also referring to other species where information on pikas is limited. We used Tinbergen's Four Questions as a framework, looking at the phylogeny, ontogeny, adaptive value, and mechanisms behind food caching.

Food Caching Behavior in Pikas

Pikas graze on vegetation within their territory throughout the year to sustain themselves. Their specific diet is dependent on location, but they are known to consume grasses, sedges, moss, and lichen. In addition to grazing, the pikas also horde caches of food from July through September when plant biomass is as its peak. This behavior is known as ‘haying’, and pikas have been known to harvest entire plants for their caches. These food caches alone are not enough to sustain the pikas through winter without supplementation from grazing, but they serve as a backup food source in the event that the pika is unable to forage due to lack of vegetation, competition, or risk of predation.

Pika foraging for Penstemon in Glacier Park, Chris Peterson, www.glacierparkmagazine.com

Background Information on Pikas

Pikas, also referred to as ‘conies’ or ‘rock rabbits’, are small herbivorous mammals belonging to the family Ochotonidae. They are related by order to rabbits and hares. The family can be divided into three subgenuses: northern pikas, shrub-steppe pikas, and mountain pikas. Most species inhabit cold, mountainous regions of Asia, Eastern Europe, and North America. Recently, pikas have been the face of some campaigns against global warming as increasing temperatures have forced them to move to increasingly higher elevations.

Tinbergen's 4 Questions: A Framework for Studying Animal Behavior

In 1963, Nikolaas Tinbergen published a paper describing four areas of inquiry which he thought should be explored in order to explain and understand any animal behavior: evolution (phylogeny), development (ontogeny), causation (mechanism), and function (adaptive value). While these four areas tend to overlap, they are helpful for forming specific and approachable questions about an animal behavior.

Questions about the phylogeny of an animal behavior provide us with evolutionary explanations that describe the history of the behavior. For example, these explanations can include information about which ancestor first possessed this trait, what was the antecedent to this behavior, and what selective pressures in the past have shaped this behavior.

Questions about ontogeny attempt to explain changes in a behavior across the lifespan of an organism in terms of development. These explanations are generally concerned with the degree to which a behavior can be changed through learning.

Questions about the mechanism of an animal behavior provide us with causal explanations that describe what the behavior is and how the behavior is constructed. For example, these explanations can include information about the physical morphology involved in the behavior, molecular mechanisms behind the behavior, other underlying biological factors affecting the behavior.

Questions about the adaptive value of an animal behavior provide us with functional explanations which describe the utility of the current form of the behavior. This involves investigating how a behavior increases an organism’s overall lifetime reproductive success.