It indicates a disadvantageous environment in which the animal is no longer able to adapt in a biologically successful manner to the stressors to which it is exposed. One speaks of distressDistress It indicates a disadvantageous environment in which the animal is no longer able to adapt in a biologically successful manner to the stressors to which it is exposed. One speaks of distress when the level or the duration of stress are such that significant changes in biological function are required to survive. when the level or the duration of stressStress An animal’s biologic response in trying to deal with a threat to its internal equilibrium (homeostasis) by internal and external stressors. A failure to do so may lead to ‘distress’ resulting in an inability to cope, leading to poor welfare. are such that significant changes in biological function are required to survive.