The Temperature Sensitivity of Some American Freshwater Fishes

The mechanism involved in temperature perception, namely, areal or spatial summation from individual small skin fibers enables the fish to sense rapid temperature changes of about .05⚬C. Although the "thermal background noise" in even a "stable" aquarium environment must often reach this level of fluctuation in heat energy flow such small changes are ordinarily ignored. Acuity of perception increases on training as small thermal changes become meaningful. The mechanism by which such fine discrimination can be achieved, is discussed.