Enrichment, also referred to as environmental or behavioural enrichment, is the provision of external stimuli with the aim to produce natural and stimulating behaviours in captive animals as they would be performed in the wild. Increasing the complexity of a captive animal’s living space is an integral part of caring for captive animals as it also provides experiences that, in turn, enable the animal to adapt to a changing environment and help them to be active and alert, much like they would in the wild. It also provides an element of control for the animal over its environment [1]. Enrichment also aims to reduce stereotypical behaviour such as pacing, something commonly found in captive big cats [2]. While reducing stress is also a main goal, it should be remembered that stress is natural, built into the natural history of the tiger and in itself is not entirely bad. Indeed, stress helps to prepare a tiger for behavioural responses to stimuli often helping the animal to survive [3].
Why is enrichment important?
Animals with good mental health are likely to interact more with their environment. In turn this makes them more relaxed and explorative, as well as less inclined to be aggressive or uneasy with their surroundings. Good enrichment supports and encourages natural behaviour. Importantly, it should provide the animal with different choices, giving them a larger degree of control over their environment.
However, enrichment cannot be used as a substitute for poor environments or enclosure designs or indeed other substandard husbandry practices. It is important but does not compensate for inadequate care that causes poor welfare. It is also important to note that whilst enrichment should be performed on a regular basis, the different methods should be varied so as not to desensitize but continuously stimulate the animals. Some things however, such as physical habitat can stay the same for extended periods of time.
Types of enrichment
Captive tigers, and other felids are exciting to provide enrichment for as they are willing to play, very agile, powerful and intelligent. As such, a wide range of effective enrichment opportunities can be created helping to promote healthier, happier tigers.
There are many different types of enrichment that can be performed with different aims to optimise the tiger’s welfare. For example, enhancing behavioural, physical, cognitive and psychological wellbeing. However, the different techniques used are not mutually exclusive and can overlap.
Environmental enrichment devices (EED) are objects, either natural (i.e. branches/logs/hay etc) or manmade (i.e. Boomer balls/tyres/piñatas etc), that can be used in some way by the animal. This type of device can be used across all of the different enrichment areas depending on the specific end goal.
1. Physical/Habitat Enrichment - this is to create an environment close to the natural habitat such as providing levels, platforms, water sources, dens and hiding places. It should include a variety of substrate options, as well as variations in climatic factors, such as light, temperature and wind/humidity exposure where possible.
2. Sensory Enrichment- this type is aimed at an animals five senses:
· Smell (olfactory) – natural scents such as pheromone/prey/predator scents or packaged scent such as spices/perfume or mouthwash
· Touch (tactile) – textured EED such as straw/soft blankets/burlap/cardboard or substrate
· Hearing (auditory) – natural sounds or animal vocal recordings
· Vision (visual) – EED with different colours or the ability to move either by wind or other means, line of sight to other animals either conspecifics or prey, mirrors
· Taste (gustatory) – novel food items such as flavoured sprays or drinks, watermelons/pumpkins. These can be some of the most engaging enrichment for big cats.
3. Food/Nutritional Enrichment- this should be presented in different ways in order to push hunting and problem-solving behaviours. It can be fresh/frozen/soft/hard/heavy etc. and preferably be different to the usual diet. This can be provided as specific treats, or presented in a challenging way i.e. hidden, buried or placed in a puzzle of some kind. It can also include altered feeding routines.
4. Social Enrichment - this is to recreate the same types of grouping that would be seen in the wild and in order to facilitate grooming, territorial and mating behaviours. It can also involve social interaction with people, including keepers and visitors and though increasingly occurring, little research has been done in this area2. Other forms of social enrichment can include the use of mirrors, tiger look-alikes and even toys.
5. Cognitive Enrichment - this provides cognitive stimulation to increase the intellectual ability of an animal. It can include puzzle feeders or training sessions. Animals participate voluntarily in this type of training session to keep up established or learn new behaviour. Novel experiences can also be considered cognitive and include unusual food items, novel EEDs or strange scents.
How to go about creating the perfect tiger enrichment?
Strangely, given the large number of captive tigers found around the world, little is known about the best forms of enrichment. From what we know about wild tiger behaviour, tigers spend a large part of their time hunting, eating and performing territorial behaviour, and research has primarily been focused on enrichment to stimulate these behaviours [2].
As a starting point it is important to understand the tiger’s natural history. This means looking into exactly what a tiger would be doing in the wild, what type of behaviour they would perform, hunting techniques, athleticism, diet, the type of habitat they live in and so on. In this way the enrichment can be carefully designed to meet these tiger-specific requirements, thus promoting a wide and varied range of natural behaviours.
The enrichment provided must also challenge the tiger. This should aim to emulate the types of challenges that tigers might face in the wild. This then helps to stimulate the tiger both mentally and physically. Following on from this, the enrichment must be changed up regularly and regular novel items added providing variation and variety in the day-to-day life of the tiger.
In addition, the type of enrichment that is given should be carefully tailored to individual tigers. This can be achieved through careful observation of the tiger’s behaviour, taking into account their age and sex. Like humans, tigers have different personalities with different wants and needs. For example, throwing a large novel item into the enclosure of a timid tiger, is not going to have the same effect as giving it to a bolder tiger. Creating a personality profile is therefore a must, as it will aid in the design of specific enrichment, maximising the enrichment effect and reducing the risk of stress4. It has also been shown that tigers provided with novel environments were more likely to exhibit stress-related behaviours and physiology [5] indicating that with some new enrichment, a habituation process might be necessary [3].
Once the enrichment ideas are established, safety considerations then need to be assessed. This includes the safety of the keepers implementing the enrichment, as well as the safety of the tiger. Enrichment must be checked as safe prior to it being given to the tiger. Tigers are very strong and tend to be destructive. Items that can be destroyed such as burlap sacks, thin plastic items or tyres should all be considered very carefully to ensure that the tiger cannot get hurt by sharp edges, entangled in any part of the enrichment or even ingest parts of it when playing.
Finally, it is important to monitor and record the enrichment process. All enrichment (and subsequent new/novel enrichment projects) should be results-based, with keepers determining whether it meets the needs that it was created for. Keepers can assist this process through understanding the preferences of the tigers, thus predicting how effective an enrichment might be [6]. Enrichment can be improved upon and changed in order to ensure they are successful. In short, it should be constantly evolving to ensure success.
References
1. Sambrook, T.D. and Buchanan-Smith, H.M. (1997). Control and complexity in novel object enrichment. Animal Welfare. 6(3), pp. 207-216.
2. Szokalski, M.S., Litchfield, C.A. and Foster, W.K. (2012). Enrichment for captive tigers (Panthera tigris): Current knowledge and future directions. Applied Animal Behaviour Science. 139(1-2), pp. 1-9.
3. Narayan, E., Baskaran, N. and Vaz, J. (2017). ‘Conservation Physiology of Tigers in Zoos: Integrating Stress Physiology and Behaviour to Monitor Their Health and Welfare’, in Shrivastav, A.B. and Singh, K.P. (eds). Big Cats. InTech, London, UK. pp. 35-44.
4. Pastorino, G.Q., Paini, F., Williands, C.L., Faustini, M. and Mazzola, S.M. (2017). Personality and Sociality in Captive Tigers (Panthera tigris). Annual Research & Review in Biology. 21(2), pp. 1-17.
5. Dembiec, D.P., Snider, R.J. and Zanella, A.J. (2004). The effects of transport stress on tiger physiology and behaviour. Zoo Biology. 23(4), pp. 335-346.
6. Mehrkam, L.R. and Dorey, N.R. (2015). Preference assessments in the zoo: Keeper and staff predictions of enrichment preferences across species. Zoo Biology. 34, pp. 418-430.
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