For a Sauropod, or large plant-eating dinosaur, Amargasaurus was actually quite small. Like most other Sauropod dinosaurs, Amargasaurus had five digits, or toes, on each of its four feet, with the largest containing a large claw.
One unique feature found on Amargasaurus was a double sail. It is believed that this sail may have been used to regulate its body temperature. Another possible use was to make it look bigger.
Amargasaurus lived in a time and place where huge meat-eating dinosaurs roamed the landscape. Its smaller size made it a target for these hunters. Sails might have confused these predators, making them think Amargasaurus was larger than it actually was.