[Clyde]

Ya. Gautama Buddha was not a vegetarian.
He ate what what was given to him.

He knew his last dish was poison but he still ate them.
Some said the last dish was a dish of mushrooms but other believed, it was wild boar flesh.

Monks started to be vegetarians probably originated from China.

It was Buddha's disciple Devadatta that suggested that monks to be strict vegetarians. Buddha rejected his idea but he told him the monks can do that if they wish to.