Tortoises heat themselves from the top, sun. Heating pads put on the floor is not recommended, as the tortoise, specially a baby may not realize he is getting too hot and could burn. If place above or even on a side wall, a Kane heating pad on a thermostat then it's much safer.

Does my Russian tortoise need a heat mat?

Russian Tortoise Substrate

Including a heating pad or heat lamp (one that can heat an area to about 85-95 degrees) inside should also be considered if you live somewhere that experiences consistently colder temperatures.

How cold is too cold for a Russian tortoise?

These tortoises can handle nighttime temperatures into the low 50s without a problem. Russian tortoises do not need to hibernate to be healthy, so tortoises kept indoors and maintained at stable temperatures will never skip a beat while winter winds below outside.