Sickness behavior in animals: Implications for health and wellness

Sickness behavior represents a centrally organized suite of behaviors - depression, inactivity, anorexia, sleepiness, and reduction of grooming - that evolved in animals living in nature to conserve body resources for the high energetic costs of fever in fighting infections. The domestic scene reveals that sickness behaviors can be an early marker of infections such as mastitis in cows. Aspects of sickness behavior are markers of stressful situations such as separating a young animal from its mother. In husbandry of animals that are pets, farm animals or in zoos, markers of sickness behavior are indications of infection, or stress and impaired welfare.