Infrasonic and low-frequency vocalizations from Siberian and Bengal tigers

Abstract

Tigers have many vocalizations including chuffling, growling, prusten, gurgling, grunting, and roaring. It has been well documented that the tiger’s high-amplitude, low-frequency roars, which are thought to be territorial in nature [C. Packer and A. E. Pusey, Sci. Am. 276, 52–59 (1997)] transmit for miles. It has been suggested that because some tigers inhabit dense jungles with limited visiblity, the capacity to hear low frequency may be beneficial for sensing and locating prey [G. T. Huang, J. J. Rosowski, and W. T. Peake, J. Comp. Physiol. A (2000)]. In an effort to understand more about these low-frequency vocalizations and to provide data to other researchers testing hearing in anesthetized felids, 22 tigers, both Siberian and Bengal, are being recorded. A portable system can record from 3 Hz to 22 kHz. On-site real-time analysis of vocalizations is performed using a portable computer. Real-time and edited playback of sonic and infrasonic tiger vocalizations is facilitated by car audio speakers capable of producing frequencies from 10 Hz–22 kHz. Initial findings have documented fundamental frequencies of some roars at 17.50 Hz. Other vocalizations, including chuffling, have fundamental frequencies of 35 Hz ±5. Playback of both real-time and edited vocalizations appear to illicit behavioral responses, such as roaring, from male tigers.