do exist in Mahé and also Praslin and La Digue islands. Its lifespan is 20 years; its length is . It finds its mates by fighting with another male bat in front of the females. Echolocation Echolocation in bats is the combination of producing sound waves via a bat's vocalization, using echoes from an environment, and highly evolved ears in bats. These sound waves are projected from an origin (the individual bat) until they come upon an object and are promptly bounced back to the origin at a lesser frequency and received by the source individual. The variation in the return frequency can then be used by the individual to make a "visual" map of the environment in order for the bat to find their food or perform other tasks such as navigation as well as just communicating with other individuals in the colony. There are a few different and important variables that can affect acoustic signals and soundwaves, first of which includes time/length (temporal character) of the calls by an individual. Temporal control can be important in perceptual organization of echoes as they are returning back to a source individual from various directions and distances. A second variable is speed/rate (spectral character) at which an individual calls and is important in helping an individual to perceptually visualize their surroundings when they are flying through terrain. The speed (frequency) that an individual calls also can become faster as they close the distance between themselves and a food source, which is how they hunt flying insects such as Lepidoptera. The speed at which calls can be adjusted from an individual also is important to keep track of each echo in more complex audio terrain. In order to use echolocation effectively bats have gone through much evolution to specialize in this method of movement and hunting. The two evolutionary pathways of echolocation in the two current suborders of bats, Yinpterochiroptera and Yangochiroptera are first, that echolocation has evolved separately between the two suborders, and second, that echolocation evolved from a single point in bat ancestral history and later was lost in some, but not all, Yinpterochiroptera suborder species. There are two different structures that can be utilized for the inner ear of bats, the wall-less canal or the fenestral canal. The wall-less canal allows for ganglion axons to cluster together without restrictions and allows for more space for more neurons. The fenestral