Chapter 1, The Reptilian Spectacle - UWSpace - University of ...

3.3 Results
3.3.1 Snake Spectacle Scale Transmittance
The spectral transmittance curves of every snake sample measured in this study are plotted in Figure
3-1, which, although cluttered, clearly shows the variation encountered. With most species, the
spectacle scales exhibit relatively high transmittance throughout the so-called visual spectrum. A
gradual tapering from 750 nm is evident and could possibly be accounted for by an increase in scatter
with shorter wavelengths due to scratches and irregularities on either surface of the scale. As well,
though great care was taken to properly center the scales in the scanning beam’s path, slight
decentration would reduce the measured transmittance due to refraction. Within the ultraviolet (UV)
range (i.e. < 400 nm), significant variation is apparent in the profiles, with the degree of tapering and
the cutoff wavelengths varying noticeably between species and families. Means, minima and maxima
for each family and subfamily shown in Table 3-2. The λ50% of individual sheds can be found in Table
3-2 on page 74.
Family Subfamily Mean λ50% (nm) Min λ50% Max λ50%
Boidae 324 305 361
Boinae 319 305 361
Erycinae (Charina bottae) 351 n/a n/a
Colubridae 347 312 406
Colubrinae 344 312 358
Xenodontinae (Heterodon
platirhinos)
382 360 406
Elapidae 367 342 415
Pythonidae 318 305 334
Viperidae 317 303 331
Crotalinae 316 303 325
Viperinae (Bitis gabonica) 331 n/a n/a
Table 3-1. Means, minima, and maxima of λ50% of each family and subfamily. Subfamilies
Erycinae, Xenodontinae, and Viperinae are represented by only one species. Those values marked as
“n/a” indicate only one specimen was available for that subfamily.
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