Scrat is a sabre-toothed squirrel shown all three films.

A squirrel is one of many small or medium-sized rodents in the family Sciuridae. In the English-speaking world, squirrel commonly refers to members of this family's genera Sciurus and Tamiasciurus, which are tree squirrels with large bushy tails, indigenous to Asia, the Americas and Europe. Similar genera are found in Africa. The Sciuridae family also include flying squirrels, as well as ground squirrels such as the chipmunks, prairie dogs, and woodchucks.

《冰河世紀》里頭讓人印象最深刻的，就屬這只外形猙獰的松鼠了。這是動畫片中夸張塑造的一個角色，就算是冰川紀，也沒有這么餓到窮兇惡極的松鼠哦。

松鼠體形通常中等大小，是寒溫帶針葉林和混交林中的典型代表動物。松鼠上頜臼齒為5枚，下頜4枚，上下顎臼齒數量不一。前后肢間無皮翼。四肢強健，趾有銳爪，爪端呈鉤狀，體重通常在350克左右，雌性個體比雄性個體稍重一些。松鼠體態端莊而輕盈，體長大約為18-26厘米，尾長而粗大，尾長為體長的三分之二以上，但不及體長。