Squirrel Girl started her career at age 14 trying to be sidekick to Iron Man with her pet squirrel Monkey Joe. After politely declining her offer Iron Man and Squirrel Girl were captured by Doctor Doom however Doom would become one of the many of enemies how would be the first villain defeated by her for underestimating her power.

Squirrel Girl was next seen joining the Great Lakes Avengers after saving them from muggers, witnessing Grasshopper die, and defeating Maelstrom. Monkey Joe was soon killed by rejected GLA member Leather Boy in a Doctor Doom suit. She was soon partnered with Tippy Toe, her new squirrel sidekick. She was able to defeat Thanos, Terrax, and M.O.D.O.K and was offered a position at SHIELD because of the number of villains she has beaten but declined.

She is one of the few mutants retaining their powers after M-Day. Squirrel Girl has a big crush on Speedball A.K.A Penance and tried to get him to change back to his old ways even going so far as using a time machine in Latveria that belongs to Doctor Doom, to go to the past but accidentally goes to the future. After meeting an alternate Speedball and Mr. Immortal she is told she has things to do in the past mainly kicking Deadpool out the group.

Powers

Squirrel Girl has many squirrel like powers. She has superhuman strength and agility. She can leap several stories. She has 2-3 inch retractable knuckle spikes that can slice wood. Buck teeth that can chew wood. A 3-4 feet long prehensile tail. She has sharp claws on each digit that can be used for climbing. She can speak and understand squirrel's language and they seem to be able to understand her speaking English. This is often the means for which she defeats her more powerful enemies as she can summon large armies of squirrels for help. She seems to have an enhanced sence of smell.  Her eyes glow in low light so she may have supervision.

Equipment

She carries a utility belt that has nuts in it for energy. She has a gryocopter called the Squirrel-A-Gig that was given to her to by Big Bertha. She also carries 'Iron Man Vs. Series battle cards' which rank villain and hero skills and abilities.