Get reliable science

Animals continually sample and evaluate the nutritional value (i.e., PIF) of forages using their senses of taste, smell, and sight. Postingestive feedback adjusts a forage’s hedonic value (i.e., preference and palatability) commensurate with its utility to the animal (i.e., animal age, morphology, and physiology) enabling survival when both the animal’s foraging environment and nutritional needs are constantly changing. Plant species that cause positive hedonic shifts are usually highly correlated with nutritional well-being, while plant species that cause negative hedonic shifts are typically highly correlated with nutrient deficiencies and toxicosis. Hence, what makes a forage taste “good or bad” (and thus, sought or avoided) is not taste per se, but rather nutritional benefits or deficits received from forage ingestion, which are sensed by animals through PIF and linked with a forage’s taste. Animals integrate and use their senses of taste, smell, and sight to seek foods that cause positive PIF (i.e., nutritional well-being) and avoid foods that cause negative PIF (i.e., nutrient deficiencies and toxicosis), and can thus be described as possessing a high degree of “nutritional wisdom.” This process occasionally breaks down when animals fail to properly link the PIF of a particular food with its taste, smell, or sight, and their physiological means for binding, metabolizing, or detoxifying toxic compounds is exceeded. (source summary)