response to males hovering, these calls, also vocalized by males, typically have a duration of about 97 ms. Territorial songs are the most noticeable vocalizations in a colony with 10-50 tonal calls that first have an upward FM, then a V-shaped call in the middle, ending with a lower fundamental frequency that is headed by a noisy buzz. The territorial calls can last anywhere from 10 ms to 100 ms and their structure can vary throughout the day. Complex songs in mammals are rare and uncommon in S. bilineata but are used as courtship songs by males. The complex courtship songs also allow for individual identification of males by females in the species S. bilineata. These courtship calls will only happen after territorial calls are finished in the morning and before territorial calls start in the evening and require ultrasound recording systems because they are above 20 kHz, that is, out of human hearing range (About 20 Hz - 20 kHz). These courtship songs also can last for up to 1 hour while being directed at a single female. As mentioned, S. bilineata are in the same family as C. seychellensis and while there is not as much known for C. seychellensis, 4 types of calls have been categorized specifically for C. seychellensis: complex calls, orientation calls, orientation calls in open areas, and foraging calls. Complex social calls have a wide frequency range and are mainly directed at other bats with no repetition in call structure. Orientation calls are used for orientation in various terrains, usually in confined spaces. Orientation calls in open areas involve no changes in frequency or amplitude. Last, foraging calls are similar to orientation calls in open areas but include two alternating CF pulses. Lower frequencies are usually used for navigation in C. seychellensis while higher frequencies are used for prey detection when an individual is in a more clustered environment. References Further reading External links ARKive - images and movies of the Seychelles sheath-tailed bat (Coleura seychellensis) Animal Info Conservation of the Seychelles sheath-tailed bat Coleura Bats of Africa Endemic fauna of Seychelles EDGE species Mammals of Seychelles Critically endangered fauna of Africa Mammals described in 1868 Taxa named by Wilhelm Peters