How do hunger and satiety affect an animal’s feeding behaviour?

Hunger and satiety act as the primary physiological regulators of an animal’s feeding motivation, governing the responsiveness of the brain to environmental food stimuli.12

The Role of Hunger

Hunger represents a high level of feeding motivation, typically triggered by fuel depletion and the emptying of the digestive tract. As an animal’s nutritional state declines, the brain increases its responsiveness to food, facilitating behaviors such as searching, pursuit, and ingestion. This process is supported by the lateral hypothalamus, often called the "hunger centre," which promotes feeding responses.12

The Role of Satiety

Satiety is the desire to limit further food intake, occurring when internal signals indicate that fuel needs are met. These signals—monitored by the brain and various organs—include stomach distension, blood glucose levels, and stored fat content. The ventromedial nucleus of the hypothalamus acts as a clearinghouse for these inhibitory signals. When satiety signals override the positive stimuli of food, feeding motivation drops, causing the animal to stop eating.13

While these mechanisms generally maintain constant body weight, they can be influenced by external factors, social facilitation, or the priority of other biological needs, such as water balance or temperature regulation.14