This may indicate that stream noise could be used as a cue by females to enhance the attractiveness of calls, as river noise would be associated with the rocks and vegetation of the habitat of A. torrentis, and thus help provide information for where best to lay eggs. However, females of this species likely do not rely only on auditory cues in choosing a partner to mate with. Researchers have found that both auditory cues (male calling) and visual cues (in the form of male vocal-sac inflation) were attractive to female A. torrentis, but the auditory cues were more attractive than visual cues. Physiology Hearing Frogs of this species rely on hearing in order to hear the calls that the males produce. The best hearing range for females is 1.6-2 kHz in frequency, and females also prefer higher frequency calls over lower frequency calls regardless of ambient noise levels in the background. However, the dominant frequency of the calls given by the males is higher in frequency, around 4.3 Hz. This mismatch is a contradiction to the matched filter hypothesis, which states that the auditory sensitivity/range of animal calls and the actual spectral character/frequency of the calls will match to make courtship calling most efficient. This contradiction offers support to the hypothesis that A. torrentis evolved from frogs that did not live near a stream and thus the high-frequency calls evolved in the species due to the selection pressure of noise from nearby streams. The hearing of individuals of this species is also partially temperature dependent. Measures of auditory brainstem responses to determine auditory sensitivity have shown that both the auditory thresholds are higher and the latencies are longer at colder temperatures as compared to warmer temperatures for calls made at lower frequencies, but this difference in auditory sensitivity due to temperature was not found for higher frequency calls. This temperature-dependent change in auditory sensitivity indicates that while temperature changes can change auditory sensitivity around the best hearing range for females (lower frequency), they do not impact auditory sensitivity around the female-preferred frequency range (higher frequencies). Thus, these temperature-dependent changes might be adaptive for reproductive behavior in this species. Glands and toxins Bradykinin-related proteins (BRPs) have been isolated from the skin of individuals of A. torrentis. Bradykinin is a powerful endothelium-dependent vasodilator that induces a drop in blood pressure, and the contraction of the bronchi and smooth muscles in the