An investigation of the alarm response in Bufo boreas and Rana cascadae tadpoles.

Tadpoles of the western toad (Bufo boreas) and of the Cascades frog (Rana cascadae) show an alarm reaction to an extract containing chemical cues from damaged conspecifics. The mean time spent by individual B. boreas tadpoles in the half of the test tank to which the extract solution was added was significantly lower than expected by chance. Activity was also significantly greater in Bufo extract tests than in control tests. Tadpoles did not avoid an extract of another tadpole species (Hyla regilla). Rana cascadae tadpoles did not avoid areas containing Rana extract but did significantly increase their level of activity in response to the extract. These results suggest that the R. cascadae tadpole alarm reaction exists but differs from the B. boreas reaction.