The instructions below are most applicable to the tarantula spider, although they can also be used to find other spider species.
Photo by henry simpson
As soon as you've found your spider is missing, close and seal all doors and windows in the room. Chances are your spider is still in the same room, although bigger spiders (sized more than 3 inches) can manage to escape farther.
Search thoroughly the area around the terrarium, including various objects the spider may hide in or under. In most cases a spider won't run far but will hide in the nearest cover it can find. Then, check the areas near windows, curtains, and under tables. This is where most lost spiders are found.
Put out a cloth in a plate of water in the middle of the room. The higher humidity around the plate may lure your spider out of its hide. If possible, reduce the temperature in the room to about 18-21 C (65-70 F) and make sure the water in the plate is hot. You can also light some candles about the plate. Your spider is very likely to be attracted by the warm spot in a cool environment. This may not greatly increase your chances of finding the tarantula, but every little bit helps.
If you suspect your spider has already managed to escape from the original room, do the above procedures in every room in your house.
If you haven't succeeded during the day, don't despair. Tarantulas are predominantly nocturnal. They are most active at night, so this is the time your spider may want to wander. Keep the light in the room low and search continually with a flashlight.
Kids and other pets like cats and dogs should be kept away from the room(s) the spider may be hiding in, for their own safety and for the spider's safety.
Search in every room thoroughly one by one. Don't forget to check the plates with water. After you've finished searching in one room, try to isolate it as best as you can. Put a towel or something else at the door base to block the gap.
Last but not least, don't give up. There have been many reports about people looking for their tarantulas for as long as a week, and even more sometimes. Make sure there's water available at all times for your spider, and keep searching.
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