In humans, a species-wide right hand bias is well documented but hand preference is not as well understood in other primate species. Although many studies have examined handedness within individual primate populations, few have compared the levels of handedness between species. This study explores whether there is a spectrum of handedness in primate species; a spectrum that mirrors the neural development of symbolic language comprehension. Similar to Peter MacNeilage's (1987) "postural origins" theory, this study investigates the hypothesis that handedness developed alongside neurological capabilities. As the left side of the brain grew to accommodate the neurons needed for speech, the right side of the body became dominant. I hypothesize that the degree of right handedness will increase in species that rely heavily on kinship and communication for survival. For this reason, it was hypothesized that gorillas (Gorilla gorilla) and ring-tail lemurs (Lemur catta) should show a higher degree of handedness than siamangs (Symphalangus syndactylus), whose brains are more specialized for locomotion. This hypothesis was not fully supported and reasons underlying the unexpected results are explored. Data were collected on captive gorillas and siamangs at the Cheyenne Mountain Zoo in Colorado Springs, Colorado. Wild ring-tail lemurs were observed over a period of 1.5 months at Beza Mahafaly Special Reserve in Madagascar. All of these populations were observed for hand preference using continuous focal sampling. Population-wide handedness trends were found. Gorillas demonstrated the most pronounced right handed bias using their right hand for 55.6% of hand usages. Siamangs did not show a handedness bias and used both of their hands for 38.6% of actions. The wild ring-tailed lemur population showed a left hand biases, using their left hand for 39.1% of actions. The implications and reasons behind handedness theories are discussed.