Biggest Bat Tongue

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Biggest bat tongue described in a report in Nature, vol 444, p705, 7 Dec 2006. Nathan Muchhala, a biologist at the University of Miami has found a bat that has the longest tongue relative to its body size ever observed. The bat is named Anoura fistulata and lives in the cloud forests of South America, where it feeds on nectar from long funnel shaped flowers. When fully extended, the bat's tongue is one and half times its body length, which makes it proportionally the longest tongue of any vertebrate except chameleons. Unlike all other mammal tongues, which are attached to the base of the mouth, A. fistulata's tongue is attached down in its chest, where it is surrounded by a sleeve of tissue called a glossal tube anchoring it between heart and the sternum (breast bone). A retractor muscle extends from the base of the tongue down to the bottom of the sternum. The bat seems to be the only pollinator of a particularly long tubular flower named Centropogon nigricans. This flower is so long and narrow that other bats could not reach the nectar in the base of the flower. Because of the close match between the bat and flower Muchhala commented: "After the initial evolution a glossal tube the extreme tongue length of A. fistulata probably co-evolved with long flowers such as C. nigricans."

Editorial Comment: Muchhala's comment is a typical evolutionary "Just So Story" that leaves more questions than it answers. Which came first, the bat or the flower? Why would a bat with a short tongue that could feed on many kinds of short flowers evolve a glossal tube so it could grow a long tongue that would be a burden if it didn't have an essential function? Why would a normal length flower that could be fertilised by several pollinators grow a long flower that could only be pollinated by one creature? There is no known way that genes for flower length in a plant can influence genes for tongue size in a bat, or vice versa. It is far more logical to believe that bat and flower were designed to work together, and be a sign that points people to the creative designer. (Ref. co-evolution, mammals, plants)

Evidence News 23 April 2008

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