RHINOCEROS SUTRA

The Rhinoceros Sutra is an early Buddhist text that teaches the merit of solitary asceticism for gaining enlightenment.  This is as opposed to practicing as a householder or in a community of monastics.  The goal of this is to become a pratyekabuddha.

Pratyekabuddhas are said to achieve enlightenment without the use of teachers or guides by contemplating, according to some traditions, the principle of dependent origination. A pratyekabuddha is referred to as "a lone buddha," "a buddha on his own," "a private buddha," one who wanders alone through the forest like a rhinoceros.  The reference is to an Indian rhinoceros which is a solitary animal.