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

3.2 Methods & Materials
This experiment involved the spectral transmittance and thickness measurements of spectacle scales
from shed snake and geckos skins. Comparisons were made within and between families and
correlations between spectral transmittance and thickness were calculated.
3.2.1 Shed skins
Shed skins from 43 species of snake (6 boids, 7 pythonids, 10 viperids, 3 elapids, 17 colubrids) were
collected from personally owned snakes and from generous donations by private pet owners and zoos.
The species investigated and the number of sheds from each species are summarized in Table 3-2,
which due to its length is placed at the end of the chapter on page 74. As well, sheds from 2 species of
gekkonid gecko, a giant day gecko (Phelsuma madagascariensis grandis) and a marbled gecko (Gekko
grossmanni) were locally collected.
Because moulting snakes will often soak themselves in water to assist in softening the skin,
sheds were air dried upon local collection or receipt from off-site sources. They were then stored in
paper envelopes until ready to be analyzed. This was done to prevent spoiling of the sheds which was
found to occur with hydrated sheds kept in plastic bags.
3.2.2 Spectrophotometry
Spectacle scales were cut from the shed skins and mounted with adhesive tape onto a sample holder
with either an 8 mm aperture for larger scales or a 1 mm aperture for smaller scales. The sample holder
was secured into a Varian Cary 500 UV-VIS-IR dual-beam spectrophotometer such that the scanning
beams were passed through the scale from front to back (i.e. from surface to interior). Measurements
were made in the range of 200-750 nm in 2 nm increments. Scans were performed on dry scales, as it
was found that hydrated scales would gradually dry out during the scan, resulting in slight vertical
shifts within the transmittance curves.
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