Songlike vocalizations from a Sumatran rhinoceros calf (Dicerorhinus sumatrensis)

Abstract

Within the last ten years the Sumatran rhino population has dropped 50%, and only 200–300 individuals exist, with five in captivity. Their native habitat is dense tropical forest and they are solitary, therefore much of their behavior remains unknown. Sumatrans are the smallest living rhino, standing 0.9–1.5 m tall, and are covered in coarse, reddish-brown hair. The first Sumatran rhinoceros born in captivity in 112 years, and the first calf ever recorded, is 17 months old and weighs 448 kg. At the Cincinnati Zoo this male calf was recorded from 1–3 m, using two Statham radio microphones, and one TCD-D8 Sony DAT recorder (9 Hz–22 kHz). Analysis, including power spectrums, spectrographic functions, and cross correlations were performed using National Instrument’s Polynesia. Preliminary analysis indicates that the calf’s vocalizations are similar in structure to adult Sumatran vocalizations, although there are some distinctions. ‘‘Eeps’’ and ‘‘whales’’ that are found in adult repertoires are produced by the calf. However, signals from the calf are higher in frequency, and the calf does not vocalize as consistently as the adults. The calf has yet to produce a ‘‘whistle blow,’’ which is an adult vocalization that has a strong infrasonic component.