Research Shows Felids May Need Their Leafy Greens

“Obligate carnivore” – does this phrase sound familiar? One may come across this term in a biology class, or even when looking into their house cat’s dietary needs. This means that felines must eat meat, requiring a high-protein diet (in fact, higher than many other mammals) to attain important nutrients such as taurine, arachidonic acid, vitamin A, and vitamin B12. It doesn’t matter if it’s a mountain lion preying on mice and raccoons, or a pet tabby begging their owner for a can of wet food at three o’clock in the morning – all felids require these nutrients that they cannot otherwise obtain from plant-based foods.

Cats’ bodies are built a bit differently from humans, and other mammals. They are unable to synthesize certain amino acids, such as taurine, which they instead must get from eating other animals. Some cat food brands aim to explore meatless food options for domestic cats, but biologically speaking, without meat, cats may suffer from heart problems or other ailments. 

Plant matter has been found in the waste of animal species. This is interesting, considering cats – particularly, big cats – are often thought of as having exclusively carnivorous meals. One study in Southwest China explores three possibilities for this. Firstly, the DNA of sugar- and nutrient-rich berries was identified, indicating that perhaps there is some nutritional benefit to eating berries, although this is debatable given that cats’ bodies do not properly digest plant material.

The second hypothesis is self-medication; it is thought that both cats and dogs may eat plants to help expel parasites, as well as treat inflammation. This remains inconclusive for the time being, however.

Lastly, and perhaps the most compelling of these hypotheses, is that plants aid in the expulsion of hairballs (or hair evacuation). Cats often ingest their hair as they groom; they also may inadvertently swallow fur while eating prey. The buildup of hair should not make its way to a cat’s digestive tract, as that could create a blockage. This may bring to a cat owner’s mind the all-too-familiar image of their pet eating grass, likely getting sick shortly after. It may not be pretty, but there could be a reason behind it. Although this is still not verified, it is believed that felids eat plants to promote hair evacuation, ultimately helping settle their tummies.

Let’s take into account some environmental factors – snow leopards, for example, live in northern and central Asia, in habitats where vegetation is sparse synch as scrubland to deserts. This means there is not an abundance of easy-to-eat plants where snow leopards are found. A study in Northern Nepal, however, found that plant material was identified within 62% of collected waste samples. Additionally, snow leopards have adapted to this high-altitude habitat by growing longer fur, which consequently leads to increased hair consumption while grooming. The more hair swallowed, the more evacuation must take place, or at least be more effectively done.

This method of grooming is fairly specific to cats, both big and small, making this occasional veggie diet more functional than it is nutritional; nonetheless, it very well might serve an important purpose. Otherwise, cats have classic carnivore features – from sharp molars to retractable claws, they can easily climb trees, capture, and chew their prey. Although wild cats are more often seen hunting deer rather than a paw full of berries or a blade of grass, organisms evolve in ways that best suit their needs, suggesting that cats’ consumption of plant material is no accident.

Obligate carnivores, they are – but may we suggest they could also be considered “behavioral omnivores,” as well?

References

Bradford, H. 4 Dec 2018. Carnivores: Facts About Meat Eaters. Live Science. https://www.livescience.com/53466-carnivore.html

Hart BL. 2008. Why do dogs and cats eat grass? Vet Med 103: 648–649.

Herbst M and Mills MGLL.2010.  The feeding habits of the Southern African wildcat, a facultative trophic specialist, in the southern Kalahari (Kgalagadi Transfrontier Park, South Africa/Botswana). J Zool, 280: 403–413. Available from: http://10.0.4.87/j.1469-7998.2009.00679.x

Shultz D. Mystery solved? Why cats eat grass. Science (80-). 2019. Available from: https://www.sciencemag.org/news/2019/08/mystery-solved-why-cats-eat-grass

Wegge, P., Shrestha, R. and Flagstad, Ø. 2012. Snow leopard Panthera uncia predation on livestock and wild prey in a mountain valley in northern Nepal: implications for conservation management. Wildlife Biol, 18: 131-141.

Xiong M, Shao X, Long Y, Bu H, Zhang D, Wang D, et al. 2016. Molecular analysis of vertebrates and plants in scats of leopard cats (Prionailurus bengalensis) in southwest China. J Mammal. 97: 1054–1064.

Yoshimura, H., Qi, H., Kikuchi, D.M., et al. 2020. The relationship between plant-eating and hair evacuation in snow leopards (Panthera uncia) Veggie Cat Food? Why Not All Cats Need Meat. PLoS One. 15:e0236635.