Thermotaxis is the regulation of heat in warm-blooded animals.
When it's hot, I like to cool down in the sea. Does that make me thermotaxic? I'm not a good swimmer, but in the UK that doesn't matter as the sea is generally so cold that a quick paddle is more than enough to do the job.
A thermotactic reaction is movement in a living organism as a response to temperature. If you watch a litter of puppies or piglets, you'll see that if it's warm they spread out more. When the temperature drops, they snuggle up together.