New Study: Breasts May Warm Newborns

For decades, scientists have questioned why human women possess permanently enlarged breasts, a trait uncommon in other mammals. A recent study from the University of Oulu, Finland, proposes a novel evolutionary explanation: breasts may have developed to provide warmth for newborns. This function could be vital, as infants struggle to regulate their body temperature, making them vulnerable to cold. Previous theories focused on fat reserves or sexual selection, but did not fully account for year-round breast size.

The Finnish research team conducted an experiment measuring breast surface temperatures in different ambient conditions. Their findings indicated that breastfeeding women exhibited higher breast temperatures and greater resistance to cooling compared to other groups. This suggests that breasts could transfer heat to infants held close, enhancing survival by reducing the risk of hypothermia. While this early study supports the thermal regulation hypothesis, further investigation is needed to fully understand its evolutionary implications.