Optimal Foraging Theory - Basic Variables of OFT

Basic Variables of OFT

The OFT attempts to explain predator behavior since no predator eats everything available. This is typically due to habitat and size constraints, but even within habitats, predators eat only a proportion of what is available.

E is the amount of energy (calories) from a prey item. h is the handling time, which includes capture, killing, eating and digesting. h starts once the prey has been spotted. E/h is therefore the profitability of the prey item.

Animals typically eat the most profitable prey types more than would be expected by chance since it will appear in the diet at a higher proportion than it is encountered in the environment. Predators do not, however, eat only the most profitable prey types. Other prey types may be easier to find, and E is not the only nutritional requirement. Toxins may be present in many prey types, therefore variability of diet prevents any one toxin from reaching dangerous levels. There are also other essential nutrients in all organism's diets, so it is clear that an approach focusing only on energy intake will not provide an adequate model.