The welfare of captive animals is often compromised as they live in man-made environments which don’t always successfully replicate their natural ones. In such conditions, animals often have very little opportunity to exercise the full range of their normal/natural behavioural repertoires and tend to develop severe behavioural and health problems.
One way to compensate for the inadequacies of the captive environment and to improve animal welfare is by using environmental enrichment.
What is environmental enrichment?
Generally speaking, environmental enrichment refers to the manipulation of the captive environment in a manner that caters for the needs of captive animals. An environmental enrichment plan is successful only if it takes into account the behavioural biology of the species it is targeted at and if it is tailored to the needs of the individual(s) the welfare of which it aims to improve.
What are some of the goals of an environmental enrichment plan?
To increase the occurrence of normal behaviours: Normal behaviours are species specific behaviours which are exhibited by physically and mentally healthy animals. The exhibition of normal behaviours is usually a sign of good welfare.
To decrease or prevent the occurrence of abnormal behaviours: Abnormal behaviours are those that deviate from the standard behavioural repertoire of a species. For example, stereotypic pacing in captive tigers is considered an abnormal behaviour and an indicator of compromised welfare.
To increase behavioural diversity: When an animal exhibits a wide range of species specific behaviours in the captive environment this is usually an indication of good welfare.
To encourage animals to use more of their environment: More efficient usage of the captive environment by animals means that they will engage in more activities which will allow them to exhibit normal behaviours and prevent boredom.
To enable animals to cope with their environment more effectively: When captive animals are moved to a new enclosure or if the enclosure they are currently in does not meet their needs, they often feel fear and stress. An environmental enrichment plan which offers e.g. more hiding places may help animals feel safer, cope with negative feelings and adjust to the new environment more smoothly.
Types of environmental enrichment
There are four main types of environmental enrichment:
Food enrichment: In the wild, animals have to work for their food. In the captive environment food is readily available and requires no work to obtain. The parameters of food enrichment include the frequency, amount and manner in which food is presented. With this type of enrichment food is usually presented in a manner that requires some work to be obtained e.g. hidden or scattered throughout the enclosure. Food-based enrichment aims to elicit natural foraging behaviours and it can promote activity, more enclosure use and mental stimulation (e.g. with the use of puzzle feeders).
Physical enrichment: This type of enrichment has to do with manipulating features such as enclosure size, substrate, toys, puzzles, furniture etc.; things that animals can explore and interact with. Physical enrichment in some cases is essential for animals to display vital behaviours. For instance, including branches in a pygmy marmoset (Cebuella pygmaea) enclosure is crucial as they use these not only for climbing and leaping but also for scent marking.
Sensory enrichment: This type of enrichment provides animals with different types of sensory stimuli (e.g. visual, auditory, olfactory, tactile) which aim to stimulate the animals’ senses. For example, the use of pheromones in captive lions’ (Panthera leo) enclosures can increase the occurrence of play behaviours and social interactions (Martínez-Macipe et al, 2015) which researchers have found to improve animal welfare in captivity.
Social enrichment: This type of enrichment refers to the interactions of animals with conspecifics and members of other species including humans. Choosing to house animals with other members of their species or in mixed species exhibits can be an enriching experience, depending on the species. For example, most primate species are social so it is beneficial for them to be housed with conspecifics. Whether interaction with humans (e.g. keepers or visitors in a zoo setting) is enriching for animals, is also a species specific topic.
Enrichment for different categories of animals
Environmental enrichment is an effective tool which can improve the welfare of animals in any situation. Although it is largely associated with captive zoo animals, it can be used to improve the welfare of other categories of animals including farm, laboratory etc. It can also be used to improve the welfare of companion animals, which, although are not captive in the strict sense of the term, usually live in man-made environments which are not always tailored to their needs.
You can find more information on how to improve the welfare of animals in captivity in ADL’s online Zoo Keeping course. If you are interested in learning more about how to improve the welfare of other animals with environmental enrichment and other methods, check out the range of courses in Animal Care offered by ADL.
References
Martínez-Macipe, M., Lafont-Lecuelle, C., Manteca, X., Pageat, P. and Cozzi, A., 2015. Evaluation of an innovative approach for sensory enrichment in zoos: semiochemical stimulation for captive lions (Panthera leo). Animal Welfare, 24(4), pp.455-461.
Mills, D.S. and Marchant-Forde, J.N. eds., 2010. The encyclopedia of applied animal behaviour and welfare. CABI.
Young, R.J., 2003. Environmental enrichment for captive animals. Blackwell Publishing.