I noticed my iguana's appetite declined significantly last fall. I figured out that his night time temperature was falling too low... I was just suspicious at first so I bought a ceramic heater and put it on a timer to run at night time only. The result was immediate. My iguana started eating regularly again and ever better than before. It really is important, I think, to watch your terrarium's temperatures and go with settings you find after doing research for your specific pet. Perhaps it is important to remember that most reptiles come from climates that don't have drastic changes in weather season to season and that when it is cold outside(winter) it may seem warm to you inside your house, but the cold outside has actually dropped the temperature inside your house and therefore your terrarium.