Why Did The Galapagos Tortoises Have Necks With Different Lengths?

Why Did The Galapagos Tortoises Have Necks With Different Lengths? Tortoises occurring on more arid islands had to stretch their necks to reach branches of cactus and other vegetation. Consequently, these later individuals had longer necks and a high peak to the front edges of their shells, which enabled them to stretch their heads almost