Activities are those that disappear from an animal's repertoire when demands upon the animal's time are very severe. An animal normally spends a certain amount of time each day feeding, sleeping, defending its territory, etc. The amount of time it needs to complete each task depends upon the prevailing environmental circumstances, and upon the animal's state of motivation. For example, when food is scarce, an animal will have to spend more time foraging than when food is plentiful.
When demand upon an animal's time is severe, certain aspects of its behaviour will be curtailed. These will generally be the less essential activities, such as sleep, grooming, and play. When time is very short, some of these less important activities may be abandoned altogether. These are the leisure activities. In other words, leisure activities are those that show the least resilience to the pressures of time.
In artificial environments, such as zoos, where animals are kept in captivity, an animal may have too little to occupy its time. Such animals normally have their food provided, and some activities, such as territorial behaviour may be totally precluded. When an animal's daily activities take up less time than is natural, it will generally sleep more, and may develop symptoms of boredom.
Subjects: Zoology and Animal Sciences — Sports and Exercise Medicine.