Behavioral enrichment to any animal

Behavioral enrichment, also called environmental enrichment is an 'animal husbandry principle that seeks to enhance the quality of captive animal care by identifying and providing the environmental stimuli necessary for optimal psychological and physiological wellbeing'.^[1] The goal of environmental enrichment is to improve or maintain an animal's physical and psychological health by increasing range or number of species-specific behaviours, increasing positive utilisation of the captive environment, preventing or reducing the frequency of abnormal behaviours such as stereotypical behaviors, and increasing the individual's ability to cope with captive challenges. In principle, enrichment can be beneficial to any relatively intelligent animal, including mammals, birds, and even octopuses.^[2]
Environmental enrichment may be offered to any animal in captivity, including:

• Captive animals in zoos and related institutions.^[3]
• Animals in sanctuaries.^[4]
• Animals used for research
• Animals used for companionship, e.g. dogs, cats, rabbits, etc.

Types of enrichment

Any novel stimulus which evokes an animal's interest can be considered enriching, including natural and artificial objects, scents, novel foods, and different methods of preparing foods (for example, frozen in ice). Most enrichment stimulus can be divided into six groups:

• Sensory, this category stimulates animals' senses: visual, olfactory, auditory, tactile, and taste.
• Feeding, this is how keepers make feeding time fun and challenging. Different methods of food presentation encourage animals to think and work for their food as they would in the wild.
• Manipulative Toys, these are items that can be manipulated in some way via hands, feet, tail, horns, head, mouth etc. simply for investigation and exploratory play.
• Environmental, this category enables the keeper to enhance the animals' zoo habitat with opportunities that change or add complexity to the environment.
• Social, the opportunities to interact with other animals.
• Training, training animals with positive reinforcement.

Puzzles that require an animal to solve simple problems in order to access food or other rewards are considered enrichment. Additionally food collecting and/or gathering contributes to behavioral enrichment and provides occupation. Quite elaborate systems of food presentation (dead rats) have been developed (e.g. in Switzerland for wild cats), where computer programmed various mechanic devices allow the animals in the enclosure to search for prey as in their natural environment. An animal's environment may also be enriched by the presence of other animals of the same or different species. A stimulus can be considered enriching even if the animal's reaction to it is negative, such as with unpleasant scents, although stimuli that evoke extreme stress or fear should be avoided, as well as stimuli that can be harmful to the animal. Enrichment can also be auditory which may include animal sounds and music.
Many people also believe that a behavior modification program (animal training) can also be enriching to a captive animal. Also the use of behavioral training, as another method of behavioral enrichment, has often contributed to the animals well-being as well as allowed zoos to improve dramatically their ability to care for animals, while reducing animal stress and increasing safety for both keeper and animal during care procedures.
Enclosures in modern zoos are often designed with enrichment in mind. For example, the Denver Zoo's exhibit Predator Ridge allows different African carnivore species to rotate among several enclosures, providing the animals with a larger environment and exposing them to each others' scents.