Nature Ecology & Evolution

A long-standing theory that human childbirth is uniquely difficult has been challenged by new research showing other primates also face high-risk births due to narrow pelvises. A study in Nature Ecology & Evolution reveals infant death rates in some primates exceed 34 percent, disputing previous assumptions. The research corrects flaws in earlier work by Adolph Schultz, who misrepresented fetal head orientation and pelvic measurements in primates.

A study suggests that early animals' reliance on asexual reproduction slowed evolutionary diversification for millions of years until environmental pressures prompted a shift to sexual reproduction, triggering rapid species expansion. Researchers from the University of Cambridge analyzed Ediacaran period fossils, finding that asexual cloning reduced competition, while stressful conditions like storms and tides later drove increased dispersal and diversity.