Social stress in tree-shrews: Problems, results, and goals

TLDR: Whereas physiological research on stress was originally the exclusive province of medicine and psychology, stress responses have also been of interest to zoologists for some years, because they can contribute to an understanding of self-regulation in mammal ian populations.

Abstract: \"S t ress\" is an ancient and familiar English noun, but its meaning in current usage is not at all widely understood. The term has long been in use in mechanics, denoting a force that acts on an object and brings about a transient or permanent change in its shape; this change is called \"s t ra in\" . It is in just this sense that \"s t ress\" is usually used in psychology and sociology. In 1915 Cannon introduced the term into physiology with a corresponding meaning: stress is a stimulus that acts on an organism so as to \" s t r a in\" its ability to resist. A contrasting definition was given by the physiologist Selye, who brought the notion of stress into general populari ty; he called the stimulus acting on an organism the \"s t ressor\" and reserved the term \"s t ress\" for the change in the state of the individual thus produced. To every stressor (whether physical or psychological in nature), according to Selye, the organism adjusts by means of a great number of nervous and hormonal changes which act to increase the resistance of the organism; together, these are termed the \"Genera l Adaptat ion Syndrome (GAS)\". Selye regarded the reaction of an organism to such an imposed stimulus as particularly characterized by a more or less marked ac t iva t ion-cor responding to the intensity of the s t r e s s o r o f the hypophyseal-adrenocortical axis; the term \"s t ress\" thus is usually used as a synonym for \"adrenal-cortex act ivat ion\" (for a survey see Selye, 1950). Whereas physiological research on stress was originally the exclusive province of medicine and psychology (see summaries in, e.g., Lazarus, 1966), stress responses have also been of interest to zoologists for some years, because they can contribute to an understanding of self-regulation in mammal ian populations. According to a concept proposed in 1950 by Christian, increasing population density leads to changes in social relationships which result in a corresponding increase in stress, to which the animals adapt with hormonal changes. These adaptat ion reactions are primarily characterized by increased activation of the