Old One Eye was a female Tyrannosaur. She was 120 years old and the leader of her pack.
She killed and ate the crew of an air buggy immediately before attempting to eat Joe Brontowski. Earl Reagan managed to save Joe by taking out Old One Eye's eye out with an electric goad. Left for dead, she survived with Reagan's scent in her nostrils.
Her son, Satanus was killed by Old One Eye.