A: Although widespread over the surface of the body, reptilian glands are small and inconspicuous, thus preventing unnecessary evaporation of water from the body. Most integumental glands in reptiles are thought to play a role in reproductive behavior, but the glands and their social roles are not well understood. The presence of gland-like epidermal organs in lizards, as well as their number and distribution, have long been useful for taxonomic and other purposes. Based upon their topographic positions, the glands can be classified into four general categories: abdominal, femoral, inguinal, and preanal.

Some geckos, iguanids, and agamids have a series of secretory pores on the underside of the thighs and pubic region. These femoral or preanal pores are openings of follicular glands in the dermis. Femoral pores typically occur in a single series on the undersurfaces of the thighs, whereas the preanal pores generally form a V-shaped series or are in clusters in the preanal area. The number of pores present is usually the same in both sexes, but those of males are generally larger than those of females; in some species, pores are only present in males.

Figure 1 Photo of femoral pores in a six-year-old female green iguana. (Photos courtesy of Melissa Kaplan, www.anapsid.org)



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Figure 2 Photo of femoral pores in a 6-year-old male green iguana. (Photos courtesy of Melissa Kaplan, www.anapsid.org)



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Femoral glands in iguanids are composed of branching tubes and tubules in both sexes, but those of males increase in size and complexity as the individual matures; little change occurs in the glands of females. In addition, the relative length of the glands appears to vary seasonally in adult males, suggesting variation in their activity. The greatest relative sizes occur during the breeding season. Some studies have shown that the removal of gonads causes atrophy of the femoral glands in males of Lacerta, but the removal of ovaries of females produces no marked changes in the glands.

The secretions of femoral glands do not appear the same in all species of lizards. In some, the material appears to be keratin and contains little or no lipid material. However, little is known about the chemistry of the secretions of preanal and femoral glands and their biological significance is unknown.

Donald Linzey

References:

Cole, C.J. 1966a Femoral glands in lizards: a review. Herpetologica 22:199-206.
Cole, C.J. 1966b. Femoral glands of the lizard, Crotaphytus collaris. Journal of Morphology 118:119-136.