The following article should help keep the cats from waking you up at all hours of the night:
If you prefer the top row of keys to behave as standard function keys (instead of performing the special feature indicated by the icon), without needing to hold down the Fn key:
- Choose System Preferences from the Apple menu.
- From the View menu choose Keyboard (or Keyboard & Mouse in Mac OS X v10.5.8 and earlier).
- Click Keyboard, if necessary.
- Enable "Use all F1, F2, etc. keys as standard function keys."
With this option enabled, the top row of keys will act as standard function keys (F1 - F12) and not perform special functions such as volume control. To use the features shown on the icon printed on one of these keys while this option is enabled, press Fn. For example, if the above option is enabled, press Fn-F10 to toggle mute on or off.