Stone-Age men were Neanderthals in more ways than one. Finger length among Stone-Age humans indicates they were far more promiscuous than humans today, say scientists. Researchers had already determined that a smaller ratio between the length of an individual's ring and index finger is an indication of greater promiscuity among primates. By that rule of thumb, Neanderthals and other early humans were likely more promiscuous, researchers argue. Scientists believe low levels of androgens in the womb affect finger length and "maleness" in offspring.
"We have recently shown that promiscuous primate species have low index to ring finger ratios, while monogamous species have high ratios. We used this information to estimate the social behavior of extinct apes and hominids," archeology expert Emma Nelson tells the Independent. "Social behaviors are notoriously difficult to identify," notes anthropology expert Suzanne Shults. "Developing novel approaches, such as finger ratios, can help inform the current debate surrounding the social systems of the earliest human."