During the days of the ice age, Scrat took an acorn with him everywhere, hoping to find a place to store it for the winter. Scrat also went out looking for other acorns so as to further his storage, looking all over for acorns and nuts.
Scrat went on fixated with taking his acorn until he met another saber-tooth squirrel named Scratte, who Scrat fell for, forsaking his acorn for a time until he grew to miss it and returned to his acorn, leaving Scratte behind in a world of dinosaurs.
Further on in time, through a mistake, Scrat was responsible for the separation of the continents, which divided Pangaea, the singular landmass, into various continents. After this, Scrat found a paradise on Earth for himself: an island populated by advanced saber-tooth squirrels known as Scratlantis. After finding it, however, Scrat sunk it by mistake, stranding himself in a North American desert.
At some point in his future, Scrat was frozen in ice and survived the ice ages, some twenty thousand years later, washing up in a block of ice on a tropical beach. Scrat lost his acorn and found a coconut, which he treated the same as his acorn, though in storing it, Scrat started another cataclysm by mistake.
A hapless saber-tooth squirrel, Scrat underwent a number of odd experiences through his life, all while trying to store a single acorn to make it through the ice age. Scrat was protective of his acorn to the point in which he would gladly risk his own life to keep it safe from others or from harm.
Scrat was out in the frozen mountain ranges up north, looking for a place to store his acorn. Hopping this way and that, Scrat scampered through a patch of dried grass and wandered through the icy fields and patches of snow in the search for a place to bury his acorn for the winter. In a moment, Scrat found an ideal place and pressed his acorn into the ground. The acorn, however, would not go in easily, so Scrat began stomping on it, eventually sinking it into the ground. This resulted in a large crack forming, which traversed up the mountain glaciers and through much of the ice walls of the mountains, where the crack finally stopped and broke off a massive glacier.
Stunned at what had happened, Scrat looked up to see the massive glacier heading straight for him and ran away, stopping fast in his tracks as he looked back and remembered his acorn. After a good deal of tugging hard at it, Scrat loosened the acorn from the icy ground and fell back, screaming as he saw the glacier coming closer, letting up sharp pieces of ice that moved towards Scrat. Scrat ran from the ice as the massive glacier rolled after him, sliding through the land. Scrat continued to run until he saw another glacier heading towards the first glacier from the opposite direction; the glaciers collided and Scrat, having no time to run out of there, used his acorn to sled away out of there as the glaciers grew closer together. Just as Scrat reached the edge of the glaciers, where he could escape being flattened, the glaciers held him in place, squeezing him tight before shooting him out.
In midair, Scrat embraced his acorn and screamed once more as he looked and found himself free-falling back to the ground. Scrat slid on a glacier and off a small ledge, loosing his grip on the acorn, before bouncing down hard on the ledges from the mountains and finally back to the ground, where he was pinned down by his sharp teeth. Scrat unpinned himself and looked for his acorn, which fell from the sky on his head. Embracing his beloved nut once more, Scrat got up, no worse for wear and prepared to walk off. At that moment, however, a mammoth’s foot flattened him into the dirt, and Scrat, shaken, picked himself up, only to have a brontotherium stamp on him, followed by another mammoth, then a dodo, and Scrat then found himself stuck on the foot of a passing Macrauchenia, being stamped on with every step forward. The migrations had begun, with all the animals of the land leaving the north due to the ice ages.
Scrat made his way out of the migration and further north, where he found a small tree in which to deposit his acorn. During that stormy night, through much struggle and toil, Scrat moved his acorn up the tree and nearly dropped it, picking it back as it nearly fell with his teeth. Scrat then moved to the top of the tree and found a small hollow space in which to store his acorn. Feeling the bottom of it with his foot, Scrat readied himself to store the acorn in the tree by raising it into the air so as to force it in. At that moment, a bolt of lightning struck Scrat, singeing off his fur and releasing his grip on his acorn.
Scrat successfully stored his acorn in a hollowed tree and left it there for a time until he found a ground sloth named Sid on the lookout for a snack. Sid reached into the tree and found the acorn, almost eating it until Scrat rushed in and yanked it out of Sid's mouth by force. Scrat left the scene shaking an angry fist at Sid.
Scrat later went further north, where he saw a pack of saber-tooth tigers go by one day and continued on trying to store his acorn into the icy ground. At that, Scrat met up with Sid, once more, accompanied by a mammoth named Manny, toting a human baby named Roshan, and a saber-tooth cat named Diego. Manny asked Scrat for directions, asking whether he had seen any humans go by there earlier: Scrat had not seen any humans and, incapable of speaking, intended to mime that he had seen a pack of saber-toothed cats go by earlier to the three mammals by miming long teeth and claws. Manny and Sid did not realize what Scrat was referring to, so Scrat pointed to Diego; the saber suspicious of Scrat's description, stood as Scrat pointed to him and finally flicked the squirrel away. Scrat slid down an icy slope, gathering more snow so that he became a moving snowball which struck down Sid.
Scrat moved on further north with his acorn, finding an ice cavern wherein he fell down an ice slide and was separated from his acorn as he slid inside the cavern's tunnels. After he had left the ice slides, Scrat embedded his acorn into an ice wall, pleased that it was safe until he saw Sid once more, coming straight at him. Screeching in terror, Scrat tugged at his acorn, but could not pull it out and was forced into the ice wall with Sid as the latter crashed into him, only to have Diego and Manny, who was holding Roshan, crash into them as well. The ice wall was thus reduced to snow, which covered them all.
After emerging from the snow, Scrat saw that his acorn was missing and frantically searched for it. Scrat then saw a cave painting of an acorn and mistook it to be his own: Scrat rushed forward to grab it but instead rammed into a stone wall, knocking himself unconscious.
Scrat later found his acorn frozen in a block of ice and made his way out of the ice cavern. Finding a campfire near Half Peak, where the same mammals that had asked direction from him had stopped for the night, Scrat emerged from behind a rock so as not to be seen by the three. As the mammals slept, Scrat moved out of his hiding place and headed towards their fire. With that, Scrat pulled out a frozen acorn on a twig: the acorn was frozen over and Scrat had intended to defrost it over the flames. As the ice melted away, the acorn boiled, whistling as it released steam and in a moment, popped into a kernel of fluffy popped acorn, and Scrat sighed in dismay at the sight of his acorn popping.
Some time later, Scrat had headed south with the herds of other animals, finding his acorn embedded in a wall of ice. Scrat scurried up the ice wall, gets his tongue stuck before he could fall and uses his long tongue to swing to the ice wall and gets free by pulling out his long tongue, but eventually reaching the acorn, stuck as it was also in the ice wall; Scrat, with much effort, then pulled the acorn loose from the ice. At that moment, however, a faint rumbling sounded from behind the ice and a small trickle of water squirted in Scrat's face; the squirrel blocked it with his paw. Three more trickles of water all squirted out, Scrat blocking them all with his other limbs until one trickle popped through the ice and Scrat, having no other choice, plugged the hole with his snout; this caused the trickle to fill him up with water until he was propelled back by the water still in his body away from the ice wall with his acorn.
Scrat then fell down the ice wall, crashing into several pieces of ice on the way until he hit one smooth section of ice. As Scrat picked himself up, he heard a young voice calling out and the squirrel was swept aside by a young platybelodon, who was sliding down the ice as a slide while Scrat tried to move out of the slide's path. Both animals shot out of the slide and into a vast waterpark.
Personality and Traits
As a saber-tooth squirrel, Scrat was small and furry with a long, bushy tail. Scrat sported a large set of hazel eyes, two short, furry ears, a small black nose and, most notably, a long set of sharp canine teeth, the trait most shared by all saber-tooth squirrels. With slender limbs and thumbless grasping paws, Scrat was almost always in the company of his beloved acorn. Through Scrat's instincts and interests being driven on finding a safe place to stow his acorn, he was capable of much, from fighting off a school of piranha single-handedly to surviving in conditions and stress that would severely harm other animals, from being stomped on, burned alive, electrocuted and even launched into space.
Scrat was close to his prized acorn, keeping it close to him at all times and distressing or even losing his mind whenever it was lost. Scrat was obsessed over his beloved nut, a state of mind coupled with a lack of common sense and awareness to his surroundings, yet Scrat was not wholly incapable of other emotions. Upon meeting Scratte, Scrat fell in love almost at once, forgetting all about his acorn for a time.
Behind the Scenes
Scrat was voiced in all his appearances by director Chris Wedge.
Scrat's species, designated the "saber-tooth squirrel" by Wedge, who gave the species an undisclosed scientific name, was a fictional animal that he developed for the first Ice Age film, its name an amalgam of "squirrel" and "rat".
In 2011, scientists in Argentina uncovered the remains of an extinct, shrew-like mammal with long fangs which was dubbed Cronopio dentiacutus, in tribute to Scrat, which resembles Cronopio .
Originally intended to be a bit part character that only appeared in the beginning of Ice Age, Scrat proved such a success with test audiences that he was made a more important character, made mute for comedic purposes and vital to the story's advancement, for without Scrat, the first real snow and ice sequence wouldn't take place until about 37 minutes into the film. 
Writer Michael J. Wilson has stated before that his daughter Flora came up with the idea for a creature that was the mixture of a squirrel and a rat, dubbing it Scrat and deciding that Scrat was after his acorn. 
Ice Age Village
Scrat is a major part in Ice Age Village. He can be seen stealing acorns and if you tap on him you get 2,00 coins. Many decorations are also based of of scrat such as the scrat in ice. He even has his own village called Scrat's Nook where every player can visit once level 6. He can be seen sneaking in others villages and if you tap on him your awarded 5,000 coins. He even has his own game called Scrat Fu. You pay one silver elephant coin or 5 acorns to play. In the game it's very similar to the iPhone game "Fruit Ninja"". You swipe to punch piranhas similar to slicing fruit in Fruit Ninja. If you swipe a Pufferfish you lose a life such as the bomb like in Fruit Ninja. Also when you expand your village Scrat plants his acorn and cracks the ground giving you more space.