THERMORECEPTORS AND ELECTRORECEPTORS
Thermoreceptors detect changes in temperature. Specific nerve endings that feel heat are present within specialized cells and free nerve endings in the skin and tongues of animals.

Electroreceptors respond to electrical stimuli. Muscle activity can emit electrical fields that certain fish, such as sharks, make use of in locating prey. Many kinds of fish have electric organs, which are specific muscle or nerve cells that generate external electrical fields. Electric organs may help an animal determine orientation, particularly in muddy waters, where visibility and olfaction are decreased. Electroreceptors also can help certain animals communicate. For example, electroreceptors can aid in locating a mate; in certain species of fish males discharge a different frequency from females.

Some other fish, such as electric eels, have electric organs that can deliver strong shocks capable of stunning prey or attackers.

Recognition of electrical fields is a phenomenon generally found only within aquatic environments where the water acts as a conductor. Humans do not sense electrical fields, although we do perceive electrical "shocks," primarily through our mechanoreceptors.