Final answer:
Bigger animals without nails can climb thanks to specific physical adaptations. Primates use brachiation, leveraging their rotating shoulder joints, separate big toes, and stereoscopic vision, while other animals adapt different body parts for movement.
Step-by-step explanation:
Even though some bigger animals do not have nails, they have evolved other physical adaptations for climbing. Instead of nails, certain large animals developed different anatomical features to aid in climbing or moving through their environment. For example, primates, including larger species, have hands and feet that are adapted for brachiation, or climbing and swinging through trees, thanks to their arboreal heritage. Key adaptations for this type of movement include a rotating shoulder joint, a widely separated big toe (allowing for a strong grip on branches except in humans), and thumbs that are widely separated from fingers. Moreover, primates have stereoscopic vision, which provides depth perception necessary for gauging distances amid treetops.
Additionally, some species possess prehensile tails that enable them to climb and hang from branches, or they may have sticky pads on their fingers to cling to surfaces. Animals like elephants, which evolved from creatures with multiple toes, have specialized their feet into large, broad structures with toenails. These features combined with their large body mass help distribute weight and provide traction, allowing them to walk on uneven terrain and perform lifting or pushing movements, rather than traditional climbing. Beyond primates, this illustrates how different animals adapt their limbs and other body parts for various means of maneuvering through their habitats.