Chimpanzees who eat together, bond more, says a new study published this week in the journal Proceedings of the Royal Society B. The study, conducted by scientists from Germany, Switzerland, Britain and the U.S., found that wild chimpanzees in Uganda who shared their food had higher levels of oxytocin -- the "love hormone" -- present than chimps who didn't share their food.
Oxytocin, which has been previously linked to bonding mothers and their babies in both humans and primates, creates a feel-good sensation for both the giver and receiver of food in chimps, the researchers say.
"We think food sharing can help spark new friendships, whereas grooming is more for confirmation of existing relationships," Roman Wittig of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany told the AP.
Interestingly, oxytocin levels (which were tested by taking urine samples) weren't determined by whether the subject was giving or receiving food -- meaning that chimps felt the "good" sensation even if they were giving their food away.
The research provides yet another striking similarity between primates and humans. "We've known for decades that human mothers and breastfeeding children both have an oxytocin surge," Wittig added. "And if we consider breastfeeding to be a form of food sharing then there's a similar mechanism in humans."