These glands lie above a ductus endolymphaticus and are connected to the static organ. The calcium sacs lie in the lower throat and usually contain a milky calcium carbonate liquid. It is increasingly thought that the calcified endolymphatic sacs serve as calcium reserves enabling the female to produce hard shelled eggs. In favour of this theory is the fact that amongst Gekkonidae they are only found in Sphaerodactylinae and Gekkoninae, and that they are absent in Diplodactinae and Eublepharinae, which lay soft shelled, parchment like eggs. Against the theory however that is in some species that males also have endolymphatic sacs which do not contain calcium. This storage system prevents the female suffering enormous “calcium stress” whilst gravid, and simultaneously guarantees that sufficient calcium is available during the relatively short period in which the eggs are formed. There is even calcium in the endolymphatic sacs of embryos and newly hatched young. This calcium is vital to strengthen the skeletal bones of the young.
(Henkel & Schmidt, 1995)
| Female endolymphatic calcium sacs |
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| Photograph: Charles Thompson |
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| Male endolymphatic calcium sacs |
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| Photograph: Charles Thompson |
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