ANIMALS are usually as shy as most humans about having sex in public — owing to an evolutionary fear of others getting horny and trying to join in. For many creatures, a roll in the hay in full view of prying eyes can reduce the odds of successfully mating, a study has found. And it could spark jealousy or unsettle social groups that work together to hunt or raise offspring — all reducing the chances of them thriving if conceived. Confining the deed to the bedroom or a secluded spot in the forest is less likely to arouse suspicion. Experts from the Max-Planck Institute, in Germany, studied the mating practices of human cultures and 34 animals. An exception among humans is the Goajiro in Colombia, where pairs reportedly took no steps to hide their romps.