There are different types of stress responses in an animal in response to stressors: Physiological responses, Behavioural responses, Psychological responses, and/or Physical responses (fight or flight). The response depends on the choice the animal partakes in, when it is faced with danger that causes distress. Walter Canon (1871-1945), argues that there are two possible choices that an organism may choose when stress is encountered: fight or flight responses; the choice is based on careful evaluation of the situation that would derive a response.