Reproduction

Within the genus Salamandra, Alpine salamanders have an exceptional position in their reproductive behavior. They give birth to fully developed offspring, which is referred to as viviparity. The Alpine salamander is the only amphibian which is independent from water in its reproduction. Some subspecies of the Fire salamander also have developed viviparity or obligatory viviparity as adaptation to high and dry habitats in southern Spain. The whole development takes place in the uterus until the entire metamorphosis. The mating behavior of Alpine salamanders consists of 5 stages and lasts between half an hour and four hours. “False” matings between two males are often observed and wrongly believed to be “real” matings. After accepting the male Spermatophore, the female stores the sperms in the spermathacae until ovulation. The number of eggs varies from 28 to 104 eggs per ovary. Normally only one egg per uterus is fertilized, the other (embryothropic) eggs are not fertilized. They later become the nutrition for the larvae. Before hatching, the embryos are fed by resorbing their own yolk. After hatching, the larvae feed on the not fertilized, disintegrating eggs. In late larval stages, they feed on epithelial cells of the trophic zone of the uterus. In the end, the female Alpine salamander gives birth to 1-2 fully developed offsprings. They are metamorphosed and 4-5 cm large. The duration of the gestation period depends on climatic conditions and altitude. On average, it lasts 2 years, at high altitudes it may last up to five years.

Only one egg is fertilized, the other ones are nutrition for the larva(e). Source: G. Fachbach, 1990.

Baby salamander, probably one year old. Together with an adult Alpine salamander.

Bibliography:

Fachbach, G. (1990): Der Alpensalamander (Salamandra atra LAUR.) Biologie und Fortpflanzung. Österreichisches Bundesinstitut für den wissenschaftlichen Film

Greven, H. (1998): Survey of the Oviduct of Salamandris With Special Reference to the Viviparous Species. The Journal of Experimental Zoology 282, p. 507 – 525

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