Wolf packs are structured with a clear social hierarchy, led by the alpha male and his lifelong mate.
Devoted gibbon couples express affection through mutual grooming and jointly raising their offspring.
After hatching, male penguins care for the chicks while females hunt for food.
Couples of this bird species display strong bonds.
Male eagles assist in parenting by keeping eggs warm and feeding hatchlings.
If one bird in a pair is lost or dies, the other bird exhibits erratic behaviour.
These rodents mate for life, a trait uncommon among rodents.