Aliens on dark worlds might develop a very keen sense of temperature and use this for both communication and exploring their environment. While humans can sense gross changes in temperature, some animals on Earth posses thermal sensors far finer than ours. For example, the mosquito can register differences of as little as one 5-hundredths of a degree centigrade at a distance of 1 centimeter. Some fish such as the sole respond to temperature changes in the water of as little as 0.03 degrees Centigrade. The bedbug can crawl along a wall of a bedroom, sense a tiny area of exposed skin, and jump to it.
Humans sense relative temperatures. We know that one glass of tea is hotter than another. But we can’t tell precisely how hot it is. Other creatures on Earth sense absolute temperature. For example, some fish can be trained to recognize a particular temperature within 1 degree of accuracy irrespective of whether the fish came out of a previously warmer or colder environment. Some birds have the ability to maintain their nests at a precise temperature and make small alterations to the nest if it becomes a degree too hot or cold.

lots of wonderfully wacky ideas