Gray Whale Gray Whale Adaptations: The Tail << Back to Main Lesson Click on drawing to see labeled enlargement Built for Powerful Propulsion The horizontal tail is two large flukes with a notch between them. An adult's tail flukes can measure over three meters (9 feet) across and can weigh up to 180 kg (400 pounds). The tail is mostly made of strong connective tissues. It is powered by a massive muscle system. (The muscle system of a gray whale accounts for one-third of its total body weight.) As whales adapted from land animals to life in the sea, bones in the lower spine loosened up to power the tail movement. The tail?s leisurely up-and-down motion provides powerful forward propulsion. Some estimates say that this motion is the equivalent of a 500 horsepower engine mounted at the rear of the whale! These gray whales are all showing their magnificent tails. Facebook Pinterest Twitter © 1997 – 2024 Journey North. All rights reserved.