This study examined intertask consistency in handedness across multiple measures of hand use in a sample of chimpanzees Pan troglodytes. Hand preferences for 2 to 6 measures were collected from the sample, and hand preference scores were derived on the basis of the individual hand preferences for each measure. Seven of 15 possible intratask correlations were significant, with some degree of clustering depending on the motor demands of the tasks. Two overall measures of handedness revealed population-level right-handedness in the chimpanzees, although the degree of bias was reduced for chimpanzees tested on more than 3 measures of hand use. The results are interpreted in the context of several recent studies that proposed theoretical models of handedness in nonhuman primates. The historical view has been that nonhuman animals, particularly nonhuman primates, do not exhibit population-level handedness see Ettlinger, ; Lehman, ; Warren,
The evolution of primate sexual swellings and their influence on mating strategies have captivated the interest of biologists for over a century. Since sexual swellings typically function as signals of female fecundity, the temporal relation between ovulation and sexual swellings can impact the ability of males to pinpoint ovulation and thereby affect male mating strategies. Here, we used endocrine parameters to detect ovulation and examined the temporal relation between the maximum swelling phase MSP and ovulation in wild female bonobos Pan paniscus. Timing of ovulation varied considerably in relation to the onset of the MSP, resulting in a very low day-specific probability of ovulation and fecundity across female cycles. Ovulation occurred during the MSP in only
Though chimpanzees and humans share about 99 percent of the same DNA, numerous physical and behavioral traits separate us from our closest living relatives. But are we different even when it comes to sex? Just how do chimpanzees "do it?
I could feel my breasts moving freely inside my loose dress. Just as I passed him, I reached back and scratched a non-existent itch on my right butt check, lifting my skirt to get to the right spot. As a result the desk guy was treated to a brief, but clear view of my stocking tops and most of my right ass cheek.