Pica is appetite for non-food substances or an abnormal appetite for some food ingredients like flour, raw potato, raw rice etc. Deficiency in Calcium, Iron or Zinc, is sometimes seen as the cause for Pica. It is believed that the needs of the body drive the brain to seek and eat items that contain the minerals. In many cases, however, Pica is a sign of mental disorder.

Do animals ever eat ‘dirt’? Yes, say the experts. But for very intelligent reasons.

According to a new study, Chimpanzees in Uganda swallow a mouthful of clay to self medicate against Malaria.

It has been common knowledge that Chimps ate fine grained clay. But, experts had previously thought that chimps ate the fine-grained clay to help ward off intestinal ailments or to obtain added minerals in their diet.
But now there has been a rethink on the guess. In previous laboratory studies, it was found that extracts of the Trichilia rubescens plant were effective in fighting the parasite that causes malaria in chimps. Recent research has shown that eating the bitter leaves alone does not give the chimps the health benefit. Instead the plant's malaria medicine is activated, when fine, soil particles bind with chemicals in the leaves. So now we know why the clever, Ugandan chimps eat clay, before or after consuming the herbal medicine. The prescription says that the medicine should be taken ‘with a handful of soil’!

Experts have in the past also suspected that Chimps and other apes may treat themselves for a variety of ailments by consuming plants, earth, and other materials. Chimps are known to swallow certain leaves to help rid themselves of intestinal parasites. Of the 163 plant species Kibale (Uganda) Chimps are known to eat, at least 35 are used in humans' traditional medicine.

Apes aren’t the only animals to self-medicate. A traditional herbalist in Africa reported the story of how a young, captured porcupine, sick with diarrhea and abdominal bloating, escaped into the forest. The herbalist followed the animal and was amazed to see the animal dig up and chew the root of mulengele plant .The root was later found to be good for treating internal parasites in humans as well!

Parrots and Macaws are believed to swallow clay bits to neutralize toxins present in some nuts and fruits. Veterinarians believe that many other animals too eat soil to get a soothing, protective coating to the digestive tracts.

Sifaka, a type of lemur found in Madagascar, is the first animal known to self-medicate when pregnant. Female Sifaka eat plants rich in poisonous tannins in the weeks before giving birth. It is unclear why the Sifaka does this but researchers have tried to guess the reason. In other mammals, small doses of tannins kill parasites and stimulate milk production. And vets often use tannins to prevent miscarriage. It could be that by eating the plants, the Sifaka is protecting its developing baby!

It is commonly known that dogs and cats are self medicate by eating grass. These furry animals invariably end up ingesting in some of the hair they shed. It is believed that the animals eat the coarse grass or leaves, to induce vomiting. When the stomach contents come out, the irritating ‘hair ball’ too gets evicted!