Changes

* '''Loss of core territory facial or flank marks''': Usually due to redecoration or change of house.

* '''Loss of core territory facial or flank marks''': Usually due to redecoration or change of house.

* '''Loss of maintenance of group odour''': Temporary or permanent loss of a social facilitator cat, absence of the owner, or housing of group members apart [at a cattery] so that odour is not mixed between individuals and factions.

* '''Loss of maintenance of group odour''': Temporary or permanent loss of a social facilitator cat, absence of the owner, or housing of group members apart (at a cattery) so that odour is not mixed between individuals and factions.

* '''Failure of odour recognition of a specific individual''': Individual odour may be altered or lost if a cat is taken away for grooming or veterinary treatment such as dental work. The cat may also return home with the odour of an unfamiliar cat on it. The returning cat may be regarded as an intruder. This causes aggression or the cat may never regain its previous role in the social group.

* '''Failure of odour recognition of a specific individual''': Individual odour may be altered or lost if a cat is taken away for grooming or veterinary treatment such as dental work. The cat may also return home with the odour of an unfamiliar cat on it. The returning cat may be regarded as an intruder. This causes aggression or the cat may never regain its previous role in the social group.

* '''Introduction of a new cat''': This may exceed the population that can be supported by existing resources, or the new cat may upset existing social relationships [through despotism, competition or by increasing stress in the group]. The same effect is apparent when a recently introduced kitten reaches maturity.

* '''Introduction of a new cat''': This may exceed the population that can be supported by existing resources, or the new cat may upset existing social relationships (through despotism, competition or by increasing stress in the group). The same effect is apparent when a recently introduced kitten reaches maturity.

* '''Illness''': Conditions that alter the cat’s emotional state or interaction with other cats ([[Hyperthyroidism|hyperthyroidism]], senility, pain, hyperaesthesia, debilitation) or need for resources (conditions causing polydipsia or polyphagia).

* '''Illness''': Conditions that alter the cat’s emotional state or interaction with other cats ([[Hyperthyroidism|hyperthyroidism]], senility, pain, hyperaesthesia, debilitation) or need for resources (conditions causing polydipsia or polyphagia).

* '''Excessive population density outside the home''': existing overpopulation, new cats introduced to an area, or when a cat owner moves a group of cats into a new home in an area where many cats already live.

* '''Excessive population density outside the home''': existing overpopulation, new cats introduced to an area, or when a cat owner moves a group of cats into a new home in an area where many cats already live.