The monkey mind (kapicitta) is a term sometimes used by the Buddha to describe the agitated, easily distracted and incessantly moving behaviour of ordinary human consciousness (Ja.III,148; V,445). Once he observed: ‘Just as a monkey swinging through the trees grabs one branch and lets it go only to seize another, so too, that which is called thought, mind or consciousness arises and disappears continually both day and night.’ (S.II,95). Anyone who has spent even a little time observing his own mind and then watched a troop of monkeys will have to admit that this comparison is an accurate and not very flattering one. On another occasion the Buddha said that a person with uncontrolled craving ‘jumps from here to there like a monkey searching for fruit in the forest’ (Dhp.334). In contrast to this, the Buddha asked his disciples to train themselves so as to develop ‘a mind like a forest deer’ (miga bhūtena cetasā, M.I,450). Deer are particularly gentle creatures and always remain alert and aware no matter what they are doing. (Text taken from this site)
Not flattering, indeed. But there could be a picture of me next to this definition in a dictionary! Especially right before I fall asleep and if I happen to wake up enough for thoughts to get going in the middle of the night. When my body is still, my brain goes haywire and leaps from thought to thought: sometimes it is very difficult to shut down the swirling mental maelstrom enough to sleep. Or focus, as in the case of yoga meditation...as often as not I am composing to-do lists in my head instead of just being calm and aware in the moment.
Not sure if this is a behavior I can change, but now I will have the mental image of myself running around like a monkey looking for fruit as incentive to learn to get my brain under control!