Friendship jealousy, which can be felt when a third-party individual threatens one’s friendship by becoming increasingly close with one’s own friend, may manifest differently based on the biological sex differences of those in involved. Indeed, new research published in Evolution and Human Behavior found that women were more jealous at the prospective loss of a best friend than men and that men were more jealous at the prospective loss of an acquaintance than women. Friendship jealousy is distinct from other types of jealousy and other similar emotions. “Friendship jealousy is evoked by third-…