The size of the skull of the average American has grown significantly only in the past 180 years, scientists say.

This conclusion comes from s study of American anthropologists from the University of Tennessee, studied 1500 skulls from 1800 year until today.
Data presented at the annual conference of the Association of American anthropologists Richard Dzhantts, reported Fox news.

Americans has bigger skulls that people in Europe

The height of the skull in men has increased by 8 cubic millimeters, and the woman with 7 cc. This shows an increase of its volume by 200 cubic centimeters in men and 180 cc in women, which is approximately equal to the volume of a tennis ball.
While the volume of the skull compared with our ancestors 180 years ago has grown by 6.8% growth shows the growth of only 5.6% and the hip – 2%.
Scientists still hesitate why the pace of growth of the head was faster than the skeleton. Puzzling in some ways is the discovery that the bones of the skull complete their development much earlier than before. For example, ossification of cartilage in fontanelle in our ancestors happened to the age of 20, while the modern American that happens at 16 and 14 for boys – girls. The assumptions of anthropologists is that this is due to factors such as improved nutrition, lower maternal mortality and infant, marriages between representatives of different ethnic groups and reducing manual labor.
Obesity in Americans in recent decades also suggests changes in the skeleton, but they still have not been studied in order to identify specific figures, comment scientists. Scientists have no doubts that the hormonal background, obesity affects the growth and maturation of bone. Example of this kind has the effect arthritic changes in specific joints such as knee due to the increased weight. Such anthropological studies carried out worldwide, but it is difficult to draw any general conclusions, because there are not enough available input data for other races. Notable changes in the skull were found in Europeans, although the words of Richard Dzhantts, they are not as dramatic as the Americans.