They include the largest animal that has ever lived , the Blue Whale , which can reach 150 tonnes , and two others that easily pass 50 tonnes ; even the smallest of the group , the Northern Minke Whale , reaches 9 tonnes . They include the largest animal that has ever lived , the Blue Whale , which can reach 150 t , and two others that easily pass 50 t ; even the smallest of the group , the Northern Minke Whale , reaches 9 t.