Individuality of the advertisement call in <i>Xenopus laevis</i> (Pipidae)

Advertisement calls of individually marked male Xenopus laevis were recorded in a South African pond to test for individual vocal signatures and information content. In a blind playback test, human listeners recognised the calls of three out of four males across two consecutive breeding seasons (1993–1994) at above-chance levels, demonstrating stability of individual call characteristics. In a larger 1998 sample (64 calls from 18 males), discriminant analysis of 32 acoustic parameters correctly assigned 95.3% of calls to the correct individual. All 11 frequency parameters were strongly (negatively) correlated with body size, but none of the 16 temporal parameters. Slower click rates in the slow trill were associated with higher male body condition. These findings show that male X. laevis advertisement calls are individually distinctive and consistent over time, and that call frequency and rhythm provide reliable cues to the caller’s size and condition.