Which of the following is a sign associated with pain in animals?

Vocalization is a sign associated with pain in animals. Animals often express discomfort or distress through various vocalizations such as whining, yowling, or growling, which serve as a means of communication indicating that they are experiencing pain or distress. This behavioral response is particularly noticeable in situations where the animal feels threatened or unwell.

In contrast, increased appetite is typically not a sign of pain; rather, animals may show a decreased interest in food when they are in pain. Excessive grooming can be a coping mechanism for stress or anxiety, but it is not a reliable indicator of pain on its own. Similarly, increased social interaction is usually related to a sense of comfort and well-being rather than discomfort; animals in pain may withdraw socially instead. Understanding these signs helps in accurately assessing an animal's welfare and addressing potential health issues.