Fig 1.
Waveforms and spectrograms of female koala vocalisations.
Spectrogram settings: Fast Fourier Transform (FFT) method; window length = 0.03 s; time step = 0.002; frequency step = 20 Hz; Gaussian window shape; dynamic range = 40 dB. The two-step cluster analysis and grouped female tonal rejection calls squawks (b), squeaks (c), wails (d) and screams (e), together. Bellows (a) and snarls (f) were separately clustered as discrete call-types. NLP is signified as follows: DC = deterministic chaos, BP = biphonation, SH = subharmonics.
Table 1.
Descriptive statistics for each of the acoustic measures.
See text for definition of variables.
Fig 2.
Comparison of female and male bellow inhalation sections.
Spectrogram settings: Fast Fourier Transform (FFT) method; window length = 0.03 s; time step = 0.002; frequency step = 20 Hz; Gaussian window shape; dynamic range = 40 dB). The dark energy bands labelled (F1-F6) are the formant frequencies. Note that they are higher in female bellows.
Table 2.
Tests of equality of group means between individuals for the acoustic measures derived from each of the three call-types.
“-”= cannot be computed because this variable is constant.
Table 3.
The pooled within-groups correlations between discriminating variables and the first three standardized canonical discriminant functions are shown. Discriminating variables are ordered by absolute size of correlation within function. Correlation coefficients > 0.4 are shown.
Table 4.
Age versus acoustic features of female koala vocalisations.
Significant correlations are highlighted in bold. “b” = standardized beta coefficient.
Table 5.
Comparison of means between acoustic features of male and female koala bellows.
Significant differences are highlighted in bold.