Porque os Esquilos fazem isso. É o jeito deles de esconder comida para o frio. Se você pesquisar sobre isso, você encontrará muitos artigos sobre ele e um artigo de ssec.si.edu dizem:
If you live in a rural area, or near a park, you’ve probably observed this unique squirrel behavior. When the weather catches a chill, these bushy-tailed creatures begin what looks like preparation for a wide-scale scavenger hunt. In great numbers, these squirrels begin to bury nuts! Squirrels hide nuts this way as preparation for cold weather when otherwise food will be scarce.
E de brainstuffshow.com :
Not all squirrels bury nuts. Gray squirrels do bury things like acorns and walnuts, but red squirrels do not. Red squirrels horde their nuts in piles. As described in this article, these two different behaviors can have a big effect on a forest. Gray squirrels do not recover all of the nuts that they bury, and these nuts go on to become trees.
E Scrat é um esquilo que vive na Idade do Gelo, então esse comportamento parece paralelo ao comportamento do esquilo cinzento.