to form a close relationship with another person or animal

A hormone called vasopressin, which is active in the brain, leads some voles to stay pair-bonded for life. 一种叫做血管加压素的荷尔蒙活跃于大脑中，会导致一些田鼠终生保持配对关系。

Many coastal birds are now getting ready to pair bond, court, and nest.

a close relationship between one person and another, or one animal and another

Some researchers maintain that the pair-bond arose soon after the human line diverged from other primates.

Humans form fairly stable pair bonds but they are not unbreakable. 人类形成相当稳定的配偶关系，但并不是牢不可破的。