The Manta Ray Learning an Activity Workbook! Have fun learning about the AWESOME Manta Ray and completing the activities at the end of the book! The manta ray is the largest species of the rays. The largest known specimen was more than 25 ft across, with a weight of about 2,900 pounds. It ranges throughout tropical waters of the world, typically around coral reefs. They have the largest brain-to-body ratio of the sharks, rays and skates, a brain which is kept warm during lengthy dives to as deep as 1,600 ft in cold water. Dive into Learning With the Adventures of Scuba Jack!