Tuesday, March 31, 2015

France 2013

ISSUE DATE: 22 April 2013
STAMP SIZE:40.85 x 30 mm
STAMP DESIGN:Olivier Ciappa & David Kawena

Bats have fascinated us since the dawn of time. This small mammal, which we find the first traces here nearly 55 million years ago, nearly 1,200 species and colonized virtually every part of the globe. Named "bat" by scientists, their behavior, their feeding habits and morphology are more varied. 

The Greater Horseshoe Bat is present from Europe to Japan. Specialist hunting on the lookout and champion of aerobatics, it emits ultrasound through the nose. This envelope in his wings at rest, especially during hibernation which runs underground, often in caves or cellars. Populations have fallen sharply until the 1990s. This stamp is sold individually. 

Dogfish of Mayotte kind of very large near 1.50 m wingspan, this bat is essentially frugivorous and is particularly active in the evening. This is one of the curiosities of the fauna of the Comoros archipelago where it is protected.

The Murine Natteter is a species slow and sinuous flight, present throughout Europe, North Africa and Asia. Living up to 16 years, it is considered rare but especially a very discreet bat likes cracks in the walls and crevices. It captures its prey, butterflies and other insects in the foliage.

Eared Mountain Bat - this little bat, recently discovered in France live in the Alps and the Pyrenees, is recognizable as all his oversized ears eared. She hunts listening to the sound of its prey and likes the upper forests, mountain passes and mountain meadows.

Bat emits sounds at too high a frequency for most humans to detect and then interprets the echoes created in order to build a "sound picture" of its surroundings.

Bio sonar, is the biological sonar used by several kinds of animals. Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects. Echolocation is used for navigation and for foraging (or hunting) in various environments. 

Microbats use echolocation to navigate and forage, often in total darkness. They generally emerge from their roosts in caves, attics, or trees at dusk and hunt for insects into the night. Their use of echolocation allows them to occupy a niche where there are often many insects (that come out at night since there are fewer predators then), less competition for food, and fewer species that may prey on the bats themselves.

Microbats generate ultrasound via the larynx and emit the sound through the open mouth or, much more rarely, the nose. The latter is most pronounced in the horseshoe bats (Rhinolophus spp.). Microbat calls range in frequency from 14,000 to well over 100,000 Hz, mostly beyond the range of the human ear (typical human hearing range is considered to be from 20 Hz to 20,000 Hz). 

Bats may estimate the elevation of targets by interpreting the interference patterns caused by the echoes reflecting from the tragus, a flap of skin in the external ear. 

Some blind humans have learned to find their way using clicks produced by a device or by mouth.

There is a definitely worth watching movie - "IMAGINE" (2012) - showing life of blind people from different perspective.

Ian arrives at a Lisbon clinic for the visually impaired to teach blind patients navigational skills. The clinic’s international community greet his unorthodox methods with both anticipation and scepticism. For Ian, orientation flows from the mind and imagination - then sensory perception follows.
His methods, though effective, are not without risk... 
source: www.imaginethefilm.org

Stamp images thanks to La Poste

La Poste