Are Gorillas Vegan?

Wild gorillas are practically vegan

Goril­las are prac­ti­cal­ly veg­an. They eat plants, main­ly leaves. “There is a vir­tu­al absence of foods of ani­mal ori­gin.”

In this study (, some sci­en­tists stud­ied the diet of wild west­ern low­land goril­las, from the Cen­tral African Repub­lic. The goril­las ate about 200 dif­fer­ent species of plants. How­ev­er, they were eat­ing prac­ti­cal­ly no meat. Goril­las do not hunt. They do not fish. They do not keep chick­ens, cows, goats, or sheep. Goril­las do eat a few insects and oth­er creepy-crawlies now and then. In oth­er words, a wild goril­las’ diet is 99.9% veg­an.

How much fat, pro­tein, and car­bo­hy­drate did this veg­an diet sup­ply? By calo­rie, the diet was 2.5% fat, 15.8% car­bo­hy­drate, and 24.3% pro­tein. That’s a lot of pro­tein! Goril­las main­ly eat leaves. Leaves are low in calo­ries, but a lot of their calo­ries are in the form of pro­tein. To get enough calo­ries, a goril­la has to eat a lot of leaves. But if it eats enough leaves to get enough calo­ries, it will auto­mat­i­cal­ly get enough pro­tein.

The sci­en­tists esti­mat­ed that these wild goril­las were get­ting 57.3% of their calo­ries from the fiber in their diet. Dietary fiber includes things like cel­lu­lose, hemi­cel­lu­lose and pectin, which are found only in plants. These sub­stances are made up of long chains of sug­ar mol­e­cules. But ani­mals can­not make the enzymes to break them down into sug­ar again. Thus, they will pass through your small intes­tine intact. But in your large intes­tine, they will be bro­ken down by bac­te­ria. Bac­te­ria can make the enzymes that break down fiber. This process is called fer­men­ta­tion because it does not use oxy­gen in the form of O2. This fer­men­ta­tion process pro­duces some short-chain fat­ty acids, such as butyric acid. These short-chain fat­ty acids are an impor­tant source of ener­gy, par­tic­u­lar­ly for the cells that line the large intes­tine. To learn about short-chain fat­ty acids, click here

Pho­to by jnis­sa

One thought on “Are Gorillas Vegan?”

  1. I chose goril­las because goril­la imagery is com­mon­ly used as a metaphor for strength. I want­ed to help peo­ple grasp the idea that they can meet their pro­tein needs by eat­ing plants. If a goril­la can, they can. In oth­er words, I’m using a rhetor­i­cal tech­nique called an a for­tiori argu­ment.

    I chose not to use chim­panzees because many peo­ple are now aware that chim­panzees some­times hunt and eat their kill. How­ev­er, it would be ridicu­lous to refer to chim­panzees as omni­vores. Rather, they are her­bi­vores, pri­mar­i­ly fru­gi­vores, that are also oppor­tunis­tic feed­ers. Sim­i­lar­ly, dogs are not true omni­vores. They are car­ni­vores that are also oppor­tunis­tic feed­ers. Nor would you refer to a white­tail deer as an omni­vore sim­ply because they occa­sion­al­ly eat fledg­ling birds or dead fish. True omni­vores, such as a griz­zly bear, have struc­tur­al adap­ta­tions for a mixed diet.

    One study found that only 1.7% of chim­panzee fecal spec­i­mens showed evi­dence of a meal that includ­ed meat: Tutin C.E.G., Fer­nan­dez M. (1993) Com­po­si­tion of the diet of chim­panzees and com­par­isons with that of sym­patric low­land goril­las in the Lopé Reserve, Gabon. Am. J. Pri­ma­tol. 30:195–211. Oth­er stud­ies have shown that the amount of meat con­sumed by chim­panzees varies sea­son­al­ly, which is what you’d expect for an oppor­tunis­tic feed­er.

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