Sounds from an animal colony entrain a circadian rhythm in the cat,Felis catusL.

Actograms of domestic cats were obtained in two settings, in a large animal colony where there were many cats and people, and in isolation in sound‐attenuating rooms. For the four cats that were studied in individual isolation, freeruns were obtained in constant dark, and then recordings of sounds from the animal colony were presented once a day at the same time for eight hours. Entrainment by the colony sounds was demonstrated in three of the...