Termites: The Other, Other White Meat
Vitamin B12 is one of the two nutrients that are essential for human beings but aren’t available from a purely plant-based diet. The other is vitamin D, which isn’t truly a vitamin but is a hormone that your body can make for itself if you get some bright sunshine on your skin. Gorillas live in Africa, where there's no shortage of sunshine. The interesting question is where do they get their vitamin B12? Evidently, they get it from the insects and other creepy crawlies that they eat. Their favorites are termites--the other, other white meat.
As you can see, the gorillas just dismantle the tree where the termites are. That's probably why they don't bother using tools to fish for termites, like chimpanzees:
Except for vitamin D and vitamin B12, plants provide all the essential nutrients that people need. Plants contain minerals, such as calcium and iron, which they have absorbed from the soil. Plants contain all of the other vitamins and essential amino acids, which they have made for their own purposes. Plants are also the original source of the essential fatty acids. However, plants don’t make vitamin B12, and neither do animals. All of the vitamin B12 in nature comes from bacteria.
Some plant-eaters get their supply of vitamin B12 from the bacteria in their own digestive system, as long as they are eating something that contains the element cobalt. (Vitamin B12 contains cobalt). Cattle and sheep are particularly good at getting vitamin B12 from their own gut bacteria. They have a lot of bacterial fermentation going on in their stomachs, so the vitamin B12 is made before the food passes through the part of the intestine where the vitamin B12 gets absorbed. Such animals are called “foregut fermenters.”
Other species, including rabbits and gorillas and human beings, are “hindgut fermenters.” Their gut bacteria make vitamin B12, but only after the food has passed through the part of the intestine where the vitamin B12 can get absorbed. Rabbits solve this problem by eating some of their own droppings. Wild mountain gorillas sometimes do the same thing, usually during periods of bad weather. Captive gorillas do it a lot more often, possibly because they are bored.
On the other hand, gorillas and human beings can eat foods that already contain ready-made vitamin B12. For gorillas, that means tasty, tasty termites, which get vitamin B12 from their own gut bacteria. Modern human beings who don't want to eat termites, or any other animal products, can get their vitamin B12 from a nice, clean, and very cheap supplement. As long as their gastrointestinal system is healthy, people can even take their vitamin B12 by mouth. Vitamin B12 shots are useful for people who have trouble absorbing vitamin B12 from their food, because of gastrointestinal disease.