Skip to main content

Table 2 Classification of the 15 different syllables types and grouping into 3 different syllable classes used in this study. Ambiguous syllables or other sounds were verified by acoustical inspection

From: Ultrasonic vocalizations in house mice depend upon genetic relatedness of mating partners and correlate with subsequent reproductive success

Syllable shapeSyllable labelSyllable typeSyllable classDefinitionReferences
(<  5 ms)usultrashortShort syllablesSyllables < 91 kHz that are < 5 ms regardless of the shape[39]
(<  10 ms)sshortSyllables < 91 kHz that are < 10 ms regardless of the shape[26]
fflatSimple syllablesSyllables < 91 kHz with < 5 kHz frequency modulation[26]
ddownSyllables < 91 kHz that decreases in frequency for > 5 kHz[26]
upupSyllables < 91 kHz that increase in frequency for > 5 kHz[26]
uu-shapedSyllables < 91 kHz that first decrease, and then increase in frequency for > 5 kHz each[26]
uiu-shaped invertedSyllables < 91 kHz that first increase, then decrease in frequency for > 5 kHz each[26]
ccomplexComplex syllablesSyllables < 91 kHz that contain ≥2 directional changes in frequency and > 5 kHz modulation of frequency[26]
c2complex 2Syllables < 91 kHz consisting of 2 elements separated by 1 frequency-jump without time separation[20]
c3complex 3Syllables < 91 kHz consisting of 3 elements separated by 2 frequency-jumps without time separation[20]
c4complex 4Syllables < 91 kHz consisting of 4 elements separated by 3 frequency-jumps without time separationAdded category for our classification
c5complex 5Syllables < 91 kHz consisting of ≥5 elements separated by ≥4 frequency jumps without time separationAdded category for our classification
hharmonicSyllables < 91 kHz that have an harmonic element[26]
(>  91 kHz)uhultra highAll syllables > 91 kHz regardless of the shape[23]
ucunclassifiedSyllables that do not fit any other of the 14 categories due to background noise or that lack clearly defined spectrographic features (shape)[40, 41]