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.

《冰河世纪》里头让人印象最深刻的，就属这只外形狰狞的松鼠了。这是动画片中夸张塑造的一个角色，就算是冰川纪，也没有这么饿到穷凶恶极的松鼠哦。

松鼠体形通常中等大小，是寒温带针叶林和混交林中的典型代表动物。松鼠上颌臼齿为5枚，下颌4枚，上下颚臼齿数量不一。前后肢间无皮翼。四肢强健，趾有锐爪，爪端呈钩状，体重通常在350克左右，雌性个体比雄性个体稍重一些。松鼠体态端庄而轻盈，体长大约为18-26厘米，尾长而粗大，尾长为体长的三分之二以上，但不及体长。