Squirrel

A small mammal native to Earth. They lived on Reach until its destruction by the Covenant.

It is mentioned in Halo:First Strike in a flashback, that the young Spartan-IIs were fed squirrel during one of their war game sessions with Tango Company, where they had to capture a flag. Both teams were supposed to use stun rounds but Tango Company was sore after having been beaten many times by the Spartans, so they used live ammunition. None of the Spartans involved were injured, however. This is probably due to Tango Company's bad aim because they were stressed and angry and desperate to defeat the Spartans.