Swans are culturally
When a pair mates, their brains release a surge of oxytocin and vasopressin—the same "cuddle hormones" found in humans. This creates a permanent neurological link between the two. They spend their lives huddling together, grooming one another, and aggressively defending their shared territory against "intruders" who might try to break up the pair. 4. Gibbon Duets: Singing for Two www m animal sex com exclusive