text: Generally, at altitudes of  above sea level, a pregnancy lasts two years, and at altitudes of 1,400-1,700 m above sea level, the pregnancy lasts around three years, though anything within a 2-4 year range is considered standard. Alpine salamander embryos are unique in how they are able to take in these nutrients through a long gestation. A portion of the mother's uterine wall becomes nourishment after the salamanders have already eaten the unfertilized eggs, (called oophagy or stage 1 and 2). They then partake in epitheliophagy, or stage 3, where they ingest these zona trophica cells until birth, and have special tooth-like developments that allow it to do so without detriment to the mother.
  Physiology
  Glands and toxins
  As mentioned above, alpine salamanders have poison glands. They are known to produce some alkaloid molecules and peptide products, and thus have a mustard-like scent associated with them. Salamandra bioproduction is still a developing research area. Salamandarines are a chemical secretion produced by the skin of alpine salamanders, as well as some fire salamanders. They are neurotoxins, and are synthesized via a biochemical pathway, completely independent of dietary intake. This means that they make these chemicals within their bodies, not as a result of ingesting poisonous substances.The starting material for this nerve-block is most likely cholesterol, and it is about twice as potent as cyanide. This pales in comparison to other toxins produced by salamanders, but S. atra do not only use this powerful substance to paralyze prey: they may have antimicrobial properties that protect them against bacterial and fungal infections. Salamandorone is another biochemical compound produced by S. atra, and though it is less potent against prey it is the strongest antimicrobial weapon these salamanders have.