Orangutan Night-Time Long Call Behavior: Sleep Quality Costs Associated with Vocalizations in Captive Pongo

Table 1

Descriptive statistics characterizing night-time flanged male orangutan long calls () generated from somnographic analysis.

	Range	Mean ± SD	Test of normality
Long call duration	35.0–112.0	85.4 ± 19.5
Long call min. frequency	12.0–59.0	19.5 ± 10.1
Long call peak frequency	59.0–400.0	278.4 ± 93.5
Long call peak dB	−35.0–0.0	−10.0 ± 12.4