What is a physical sign that an animal may be stressed or anxious?

Increased vocalization, such as barking or growling, is a notable indicator of stress or anxiety in an animal. When animals experience stress, they often communicate their discomfort through vocal behaviors. These sounds can signify a range of emotions, including fear, frustration, or agitation. For example, a dog that is barking excessively may be feeling threatened or unable to cope with its environment.

In contrast, sleepiness is typically a sign of relaxation or a state of rest rather than stress. An increase in appetite can sometimes indicate comfort or a lack of stress, as anxious animals may actually eat less due to their nervousness. Lastly, a relaxed posture is associated with calmness and comfort, which would imply an absence of stress rather than its presence. Therefore, increased vocalization stands out as a clear and observable sign of an animal experiencing stress or anxiety.