Top Highlights

• One of the most dramatic examples of how desperate this battle for genetic immortality can be comes from elephant seals, where the clearly polygamous society is dominated by huge bull males who claim most of the females. Biologists calculate that only 20 percent of the males ever become fathers. And there are many similar examples—orangutans live i...
• If, then, women come less easily to risk-taking, they also move less readily to destruction and harm, at both high and low levels. Jay Belsky, Distinguished Professor of Human Development at the Pennsylvania State University, talks about risk-taking on a small scale. “Dads like to toss their babies in the air,” he says. “And I guarantee you, wait l...
• For instance, males run high in testosterone, a hormone that spikes up in times of challenge. Perhaps—and this remains speculative—the hormone also propels a quick, aggressive response. Females are high in oxytocin, a hormone that supports not only lactation but, apparently, bonding and nurturing behaviors—although this too remains speculative.
• Among the apes, the act of copulation has a breathtaking sense of hurry, averaging seven seconds for common chimps, 15 seconds for bonobos, sometimes known as pygmy chimps, and one minute for gorillas, who, after all, are big enough that most predators aren’t going to mess with them.