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Thresholds of infrared sensitive tectal neurons inPython reticulatus, Boa constrictor andAgkistrodon rhodostoma

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Boas, pythons and pit vipers are known to use the heat radiated by warmblooded animals in order to hunt them. However, until now no comparative study to determine at what range these remarkable sense organs operate has been attempted.

The results from a comparative electrophysiological study on central infrared sensitive neurons in the tecta mesencephali ofBoa constrictor, Python reticulatus andAgkistrodon rhodostoma are used to calculate thresholds and the associated maximal detection ranges. A discussion of the rationale behind radiation physics and its implications for the calculation of thresholds and the translation into a behavioural context is given.

The thresholds determined forBoa, Python andAgkistrodon are respectively: 42.28, 14.28 and 2.57 10−6 cal/cm2·s which, in biological terms, is equivalent to that which is required to detect a mouse (10 °C warmer than the surrounding, radiating area 25 cm2) at a distance of 16.4 cm, 28.3 cm and 66.6 cm.

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nucleus descendons lateralis nervi trigemini


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Recently, it became commonly accepted under taxonomists to renameAgkistrodon rhodostoma on systematical grounds toCalloselasma rhodostoma (Chernov 1957). However, the author prefers to use, in this physiologically and behaviourally oriented paper, the better known old name

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de Cock Buning, T. Thresholds of infrared sensitive tectal neurons inPython reticulatus, Boa constrictor andAgkistrodon rhodostoma . J. Comp. Physiol. 151, 461–467 (1983). https://doi.org/10.1007/BF00605462

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  • Radiation
  • Hunt
  • Electrophysiological Study
  • Sense Organ
  • Detection Range