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Science

Smallest chameleons have the fastest tongues

In the animal kingdom, smaller animals really do pack a bigger (relative) punch. This truism, which is due to metabolic demands, is almost comically apparent in the case of a record-setting chameleon species.

The rosette-nosed chameleon of Tanzania, an endemic, endangered species, is now king among the world's birds, mammals and reptiles for having recorded the highest acceleration and power output in any single physical movement.

While trying to capture prey in a laboratory setting, Rhampholeon spinosus ejected its long, sticky tongue at an acceleration rate of 264 g-forces and simultaneously generated a force of 14,040 watts per kilogram, as documented by Christopher V. Anderson at Brown University and published in his

paper

in the "Scientific Reports" journal, which is part of "Nature."

The findings fit with Anderson's hypothesis: Because small animals require proportionally more food to keep their higher metabolic rates humming, and because their food-capturing techniques must therefore be more powerful than those of their larger relatives, smaller chameleons should have more powerful mouths and tongues.

The reptile's snout-vent length - a unit of measurement running from the tip of the snout to the anus - is just 47 millimeters (two inches).

And, relatively speaking, the entire feeding apparatus of the rosette-nosed chameleon is in fact larger than its relatives: The animal has proportionally longer jaws, tongue muscle cross sections and a longer projection distance of its tongue (at 2.5 times its body length).

By comparison, Madagascar's Malagasy giant chameleon, whose snout-vent length (200 millimeters, or eight inches) is roughly four times larger than that of the record-setting Rosette-nosed chameleon, can only launch its tongue at less than one fourth the speed.

Another of the 20 chameleons involved in the study (see video) is Trioceros hoehnelii, or Höhnel's chameleon, found in Kenya and Uganda. This reptile is also relatively small, with a snout-vent length of less than 90 millimeters and a tongue extending more than twice its body length.

Generally, the rapid recoil of elastic tissues - whether in chameleons' mouths or in the legs of frogs - allows organisms to far exceed what their muscles alone could provide in terms of maximal power.

The smaller the species, the higher the efficiency of such energy amplification mechanisms.

Brookesia micra on a matchstick

Coming soon... potential record-breaker Brookesia micra

And since the rosette-nosed chameleon is not the world's smallest - that honor goes to Brookesia micra, pictured here - the current record for a physical movement's acceleration and power might soon be broken... as soon as someone travels to a small island off Madagascar and records the reptile eating in the wild.

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