Audio Gallery Flying squirrels have many vocalizations, some audible to humans, some not. More research is required in this field of study. The source of the calls are difficult to locate for mere humans and likely some predators - good thing for the squirrel, and likely designed by nature to be this way. Southern flying squirrels are, generally, much more vocal by sheer power  than their much larger northern counterparts. Northerns may possess a broader menu of vocalizations. Flying squirrel ears are the same in structure as other squirrels' ears - except for one difference. Flying squirrel ears possess a larger ear cavity, which allows them to hear better than other squirrel species. This adaptation is likely due to their nocturnal behaviour, but no one knows for sure. Audible sounds Loud things come in small packages! Southerns have a very loud, sharp "tseep" vocalization, up to down in scale. The "tseep" call is considered to be an alarm, or caution call, designed to notify other flying squirrels within earshot of something in the forest that may be, or is, a threat. Southerns also have a "chittering" vocalization, usually following, or framed by, an alarm call. Another vocalization from southerns is a snorting sound when challenging a flying squirrel of the same sex but of lower ranking in the hierarchy. They can "chucke" too. Northerns utilize a very low-volume "seep" call. We have monitored, with a parabolic microphone, the vocalizations of wild  northern flying squirrels for a period of time. One thing we have noticed is that this "seep" call is employed by a family group, usually consisting of a mother and her offspring. We speculate this is to notify group members that all is well, and to let other group members know where each other is in the immediate area. Northerns, like the southerns, share a "chittering" sound, usually following, or framed by, an alarm call. Northerns also have a chuckle or "chuck chuck" sound.  Another vocalization is a long chortling sound, often when running (along branches or up tree trunks). They'll also, on occasion, make a soft sputtering sound when grooming themselves. Both species have an assortment of audible squeaks, snorts and squawks, especially in a nest full of juvenile flyers or when the natal nest is under threat from a predator. As Nancy Wells says, if some of these sounds were translatable, some would certainly not get a G rating! Some vocalizations are made by adult flying squirrels during their glides, and these sounds are also made by juveniles during their glides. No one knows why. Inaudible sounds Some sounds that flying squirrels make are inaudible. These ultrasonic sounds produce sound waves with a frequency above the upper limit of human hearing. Many mammals are able to hear sound frequencies much higher than humans can. Ultrasonic sounds do not travel far. Conversely, some mammals, such as whales and giraffes, can communicate employing infrasonic sound frequencies that are lower than the limit of human hearing. Infrasonic sounds can travel great distances. Ultrasonic sounds have been documented in the natal nest, and may be used by the mother to communicate to her offspring. The fact that these sounds have been noted opens up a pandora's box. Do they communicate in ultrasound as adult to adult? Do they employ a type of sonar similar to that which bats employ for echolocation/navigation purposes? Preliminary research finds that ear design does not compare to that of a bat, but much more research is required in this field. Some sounds we have described are, well, impossible to describe! We'll be adding more sounds later to help you understand what we are talking about! ========== Northern flying squirrel distress Southern flying squirrel alarm call