Ganesha is usually regarded as the elder son of Shiva and Parvati. Ganesha is represented with an elephant’s head-an emblem of sagacity-and is frequently attended by, or is riding upon, a rat. He has generally four hands, but sometimes six, or eight, or only two.
The Inch Shiva Purana Inch relates that, after giving Ganesha life, Parvati placed him at her door to prevent intrusion whilst she was bathing. On his refusal to allow Shiva to enter, a struggle ensued, in which that deity cut off Ganesha's head; but when Parvati showed her husband that it was by her orders that the door was closed, and wept because of the loss of her son, Shiva ordered the first head that could be found to be brought to him; this happened to be an elephant's which he fitted to the headless trunk and resuscitated his son.
Ganesha has only one tusk, and hence is called Ekadanta. The reason of this is as follows :-Parasurama, who was a favourite disciple of Shiva, went to Kailasa to visit his master. On arriving at the inner apartment, his entrance was opposed by Ganesha, as his father was asleep. Parasurama nevertheless urged his way, and after a long dialogue, the two came to blows. Ganesha had at first the advantage, seizing Parasurama in his trunk, and giving him a twirl that left him sick and senceless. On recovering, Rama threw his axe at Ganesha, who, recognizing at as his father’s weapon-Shiva Having given it to Parasurama-received it with all humility upon one of his tusks, which it immediately severed, and hence Ganesha has but one tusk. Parvati was highly incensed at this, and was about to curse Rama, when Krishna, of whom he was a worshipper, appeared as a boy and appeased her indignation. Brahma is said to have promised that her son should be worshipped before the other gods.