Animals learn to reconqnize and follow the 1st moving object
Neural Control of Filial Imprinting
The birds are use to each other since was born. When they are born they saw each other and know are family.
When dogs are born like people they are with their brother and sister.They will know them for rest of life.
The monkeys are cleaning each other like that is in their blood.
Most animals are not monogamous. Many animals receive no parental care at all. If a young female is raised by her mother with no father around. Sexual imprinting is a general imprinting; it is not specific to individuals, only species typical characteristics. The more general system of sexual imprinting allows young to learn to recognize potential mates without inbreeding.There are many examples of offspring raised by foster parents of a different species preferring to mate with the foster species over its own species. Lorenz's geese were more sexually attracted to humans than to other geese. Goats raised by sheep mature and prefer to mate with sheep, and sheep raised by goats prefer to have goats as mates.
The baby kangaroo is appended to its mother since it was born.
Dog and Baby Lions
This dog is the "mother" to the baby lions because they are use to her other than the babies real mother.
The birds are waiting for the food that their mother is going to get.