As nursing mammals, baby elephants, also known as calves, have a strong sucking instinct that is part of the animal's survival skills; however, though this instinct has a definite practical purpose, it also can lead to the elephant calf sucking its trunk as a means of self soothing. This habit is similar to that of a human baby or child sucking its own thumb as a comfort mechanism, though even adult elephants can continue this behavior, which is not exactly socially acceptable in adult humans. However, elephants do put their trunks to their mouths for other reasons, including pouring water in their mouths for drinking and sucking on the trunk to better understand a smell.
Baby elephants can be quite clumsy with their trunks as they learn how to control and use this appendage. The trunk is an important part of an elephant's anatomy; it's used for a variety of purposes, from the practical (eating and drinking) to the social. Elephants will use their trunks to caress and even embrace other elephants. This prehensile appendage is used as a tool for lifting and carrying. Adult elephants may even use their trunks to guide and nudge other elephants, particularly calves, sometimes even helping to pull or lift calves and adult elephants that are stuck.