Under most situations a real regular mother earth raping incandescent 100 watt bulb is adequate. If not bring the fragile critters in the house for the night.
ex-sister in law lost their house to a space heater used to keep a couple of pet rabbits warm. Nobody hurt but the fire took a Corvette, a Mustang and a Triumph triple.
On a related note, the replacement Corvette was totaled yesterday when a texting driver ran a red light, no serious injuries.