This is Wagner’s mustached bat (Pteronotus personatus), a somewhat ridiculously named bat which is a master of echolocation.  The little flying insect hunter is tiny:  bats have a body length of 6 to 6.7 centimetres (2.4 to 2.6 in).  They are strictly nocturnal insectivores.  They fly over rivers at night feeding on moths and mosquitoes.  Wagner’s mustached bat is notable as one of only a handful of Doppler-shift compensating bats in the new world: the little animals.  To quote Michael Smotherman’s article in The Journal of the Acoustical Society of America , Wagner’s mustached bats “adjust the frequency of their [Constant Frequency] component to compensate for flight-speed induced Doppler shifts in the frequency of the returning echoes.” This is no mean feat for an animal without any onboard computers or slide rules.

Pteronotus personatus04el

Wagner’s mustached bat ranges from southern Mexico, down through Central America to the Pacific coast of Ecuador. It is found in a broad swatch of South America in a band through Colombia, Peru, Bolivia, and across central Brazil to the Atlantic.  Not only does the bat intuitively understand Doppler shift effects, it also exhibits an interesting coloration feature.  The species has two color phases: some bats are sable colored with grey underparts; others are reddish-orange with cinnamon colored underparts.   Ferrebeekeeper needs to talk about polymorphism (maybe later this week) and this little mustached creature is a good start on explaining the concept.