Tip Tuesday: If Your Tarantula Needs Winter Heat, Warm the Room, Not the Floor
If your house dips into the 60s overnight, you might be tempted to stick a heat mat under your tarantula’s enclosure. Today’s tip: for most commonly kept tarantulas, a comfortable room is enough. If you do add heat, warm the space around the enclosure, not the floor under the spider.
Room temperature usually covers it
Tarantulas are tougher about temperature than many care sheets suggest. Tom Moran of Tom’s Big Spiders, a longtime keeper, writes that most species do well from the high 60s to the mid 80s °F, and that a home holding 67–70°F through winter doesn’t need extra heat. A cooler spider may eat less and grow more slowly, but that isn’t an emergency. Dr. Krista Keller, a zoological medicine specialist at the University of Illinois, gives a slightly warmer 70–85°F for most pet species. Species vary, so check your spider’s own care notes.
Why the floor is the wrong place for heat
Many tarantulas dig, or at least hunker down in the substrate, when conditions above get uncomfortable. A heat mat stuck under the floor warms and dries the exact layer that’s supposed to be their refuge. Big Apple Herp’s care guide warns that a spider may burrow toward that heat and end up dehydrated or overheated. Moran puts it more bluntly: no heat mats, heat pads, heat rocks, or heat lamps, because all of them can create hot spots that injure or dry out a tarantula.
Where the sources disagree
This isn’t unanimous. Dr. Keller’s list of options includes under-tank heaters alongside ceramic heaters and whole-room heat. Britain’s Amateur Entomologists’ Society also suggests thermostat-controlled mats or cables for unheated rooms. Even Moran notes some experienced keepers run mats on a controller, usually to warm a whole cabinet of enclosures. The common ground is the useful part:
- Heat the space, not the spider. A thermostat-controlled space heater in the room, or a warmed cabinet, gives the gentlest, most even warmth.
- No light. Dr. Keller says the heat source shouldn’t emit light, and tarantulas tend to avoid bright light.
- Measure inside the enclosure. Keep a thermometer in the tank so you know what the spider actually feels.
- Leave somewhere cooler to go. Any added heat should warm only part of the enclosure, never all of it.
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Shop this designDon’t forget the dry air
Furnaces dry out the air, and that can matter as much as the temperature. Keep the shallow water dish full, which Dr. Keller says to refill daily. If your spider looks weak, shrunken, or is lying in an unusual position (and you know it isn’t molting), see an exotics vet.
New to keeping tarantulas? Our Tarantula 101 guide and our enclosure breakdown cover the full setup. If you keep the classic beginner species, see our Chilean rose hair spotlight.
The takeaway: before buying a heater, check the room. If it really is too cold, warm the air around the enclosure and keep the floor cool enough to retreat into.
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Alex Johnson stands at the forefront of exotic pet expertise, with a particular affection for the misunderstood beauty of tarantulas. With years of experience caring for a range of unique animals, from sugar gliders to chinchillas, Alex brings a wealth of knowledge to the exotic pet community.
