Now a study published today in Current Biology offers some insight into why our archaic brethren were so much beefier. Featured VideoAn international team of evolutionary anthropologists discovered the Neanderthal growth hormone receptor has some slight alterations compared to ours. When they cultured muscle cells expressing the Neanderthal receptor, they responded more strongly to human growth hormone, growing 40 percent larger than normal cells. Its effects likely start around puberty, when growth hormone production kicks into high gear. It cannot explain the Neanderthal body type on its own, and it certainly doesn’t determine a person’s overall appearance.”