Recently published results of postearthquake interviews with animal owners in two epicentral areas seem to indicate that animals behave unusually before some earthquakes. A review of the environmental circumstances surrounding one even that yielded positive results (the 22 November 1977 M=4.7 Willits, Calif., earthquake) shows that, in addition to possible geophysical earthquake precursors, three factors not known to be related to the ensuing earthquake may have caused the observed behavioral anomalies: (1) unusually heavy rainfall and local flooding, (2) a relatively large change in barometric pressure, and (3) a very large enhancement in solar-flare cosmic radiation at ground surface. A modified approach in future studies of behavioral anomalies is recommended that would include an evaluation of all important behavioral stimuli in the local environment before the associated earthquake.