Eating Grass
While tigers are obligate carnivores, they will eat grass and other plants such as bamboo as part of their digestion process. It’s likely this is because tigers will eat the stomach of their prey which inevitably holds foliage of some kind, albeit partly digested. They need access to this in captivity as they’re less likely to encounter grass in their food or be given stomachs to eat!
Having grass in the enclosure is therefore necessary. In some instances or times of the year, due to weather (a particular problem in Thailand during the dry season), grass might die out in the enclosure. It’s therefore important to provide grass in another form as part of the enrichment process. It doesn’t just have to be grass though, there are other leaves such as those from bamboo trees and (specific tree in the temple!) that the tigers will also eat.
Cooling off with Ice pops
Providing tigers their food in novel ways is a great enrichment technique. Making blood popsicles is a great way of providing something new. Not only does it provide a different texture, but it’s also cold which can be refreshing to tigers living in a hot environment. Giving ice balls to lions has shown an increase in standing, moving, sniffing, licking, gnawing and paw manipulation [1,2]. Frozen fish has also proven effective [3].
Altered feeding routines
Traditionally, captive animals are fed once or twice a day [4]. Usually, feeding ensures the right nutrition is provided to the animal, but what is not provided is the opportunity for animals to utilise their natural feeding behaviour [5] such as foraging or hunting. Studies on a variety of different animals show increased foraging reduced passive, agonistic and stereotypic behaviours indicating that providing food in novel ways is important to improving captive animal welfare [1]. With this in mind, if it’s possible, changing feeding times can reduce expectant stereotypies and closer emulates wild feeding habits.
Provision of carcasses
Most zoos or captive settings will at least provide an adequate diet in terms of nutrition for their captive tigers. However, providing more than the bare minimum can have a positive effect in different ways. The provision of live fish to a fishing cat stimulated greater activity, increased hunting behaviours and a diverse range of behaviour. Behaviours remained 7 days later [4]. Occasional use of live prey is a strategy used to reduce stereotypies specifically when the pacing has been caused by displaced feeding behaviour [1, 6], with tigers showing increases in hunting behaviour when exposed to live fish [7]. However, in many countries, the provision of live prey is prohibited as it causes the prey species to experience poor welfare and suffering which means other methods of encouraging prey behaviour have to be created – see cognitive enrichment.
The provision of carcasses such as the hind limbs of a horse has also shown to decrease stereotypic behaviours of tigers [1], and other red meat such as beef or deer can also be provided to provide similar enrichment. The provision of larger carcasses will help prolong feeding time and stimulate more natural tiger behaviour [8] such as licking to remove the fur or skin, dismemberment, carrying to keep the prize in a safe place to consume and can even be used to emulate natural feeding patterns encouraging the tiger to eat a large portion in one sitting and then go without. However, carcass feeding doesn’t always elicit continuous positive behaviours so this form of enrichment will need to be assessed based on the specific tiger’s needs [9].
Following on from this, a number of zoos will employ a fast/starve day (or two) per week within the feeding regimen of the tiger [10]. This is to follow more natural tiger eating patterns as tigers will gorge on a successful hunt, but then often fast for a few days after, before they are successful once again.
When it comes to the quantity of food, this will vary between subspecies, gender and age of the tiger. Experienced keepers should know the correct portioning of food to ensure the tigers maintain a healthy body condition and weight. Wild tigers can put away as much as 20kg of meat in a single sitting. However, captive facilities will feed captive tigers less than this per day as they are not as active as their wild counterparts and would therefore gain weight.
Making it balanced
While providing all of these different options, the diet also needs to be balanced. Despite being a natural diet, simply feeding a raw carcass to a tiger is not enough. Big cats like tigers often suffer from various nutritional deficiencies such as low levels of taurine, Vitamin A, D and calcium as well as a number of other minerals. Each of these has an important role to play in tiger health: taurine for vision; calcium can help prevent bone disease and vitamin A and D help keep the digestive system healthy [6]. There are a number of carnivore supplements that address these vitamin and mineral deficiencies, and these can be placed inside the meat so that the tiger keeps a well-rounded diet.
References
1. Bashaw, M.J., Bloomsmith, M.A., Marr, M.J. and Maple, T.L. (2003). To hunt or not to hunt? A feeding Enrichment Experiment with captive large felids. Zoo Biology. 22: 189-198.
2. Powell, D.M. (1995). Preliminary evaluation of environmental enrichment techniques for African lions (Panthera leo). Animal Welfare 4:361-370.
3. Skiebel, A., Trevino, H.S. and Naugher, K. (2007). Comparison of several types of enrichment for captive felids. Zoo Biology. https://doi.org/10.1002/zoo.20147
4. Shepherdson, D.J., Carlstead, K., Mellen, J.D., Seidensticker, J. (1993). The influence of food presentation on the behavior of small cats in confined environments. Zoo Biology. 12:203–16.
5. Lindburg, D.G. 1998. Enrichment of captive mammals through provisioning. In: Shepherdson, D.J., Mellen, J.D, Hutchins, M., editors. Second Nature: Environmental Enrichment for Captive Animals. Washington D.C.: Smithsonian Institution Press. p 262–76.
6. Dierenfeld, E.S. (1987) Nutritional considerations in captive tiger management. In TIGERS OF THE WORLD. R.L. Tilson and U.S. Seal, eds. Noyes Publications: Park Ridge, NJ, Pp.149-60.
7. Mellen J, Hayes M, Shepherdson D. 1998. Cap-tive environments for small felids. In: Shep-herdson DJ, Mellen JD, Hutchins M, editors.Second nature: environmental enrichment forcaptive animals. Washington, DC: SmithsonianInstitution Press. p 184–201.
8. Ruskell, A.D., Meiers, S.T., Jenkins, S.E. and Santymire, R.M. (2015). Effect of bungee-carcass enrichment on behavior and fecal glucocorticoid metabolites in two species of zoo-housed felids. Zoo Biology. https://doi.org/10.1002/zoo.21192
9. McPhee, M.E. (2002), Intact carcasses as enrichment for large felids: effects on on- and off-exhibit behaviors. Zoo Biology 21:37-47.
10. Veasey, J.S. (2020). Can zoos ever be big enough for large wild animals? A review using an expert panel assessment of the psychological priorities of the Amur tiger (Panthera tigris altaica) as a model species. Animals, 10 doi:10.3390/ani10091536.