- Mbutsi tribe
- Zaire (Egypt)
The smallest pygmies are the Mbutsi from Zaire, with an average height of 1.37 m (4 ft 6 in) for men and 1.35 m (4 ft 5 in) for women, with some groups averaging only 1.32 m (4 ft 4 in) for men and 1.24 m (4 ft 1 in) for women. According to medical research, pygmy children are not significantly shorter than the children of other tribes. But they do not grow in adolescence because they produce only a limited amount of the hormone called insulin-like growth factor (IGF).