Fire Salamander

Poison Behind Both Eyes

The Fire Salamander (Salamandra salamandra) wears its warning as a uniform: black skin marked with yellow or orange spots, splotches or bands. Animal Diversity Web’s account puts it at 15 to 25 centimeters long, with some individuals exceeding 30, and AnAge lists an adult weight of 19.1 grams. Its maximum recorded lifespan is 24 years, in captivity, and one study found individuals returning to the same cave to hibernate for up to 20 years. It occurs all over Europe from Spain to Greece, spending much of its time beneath rocks or logs or in crevices in shaded woodland, and is mainly active on mild nights. Older accounts extend its range into northern Africa and the Middle East, but a mitochondrial DNA study of the genus found six major lineages, and suggested S. salamandra was the only one to recolonize Central Europe after the last glaciation.

It hunts soft-bodied prey such as earthworms and slugs, and harder-bodied beetles, centipedes and millipedes. When some light is available it uses movement as its cue and ignores stationary prey. In the dark, with its vision impaired, it hunts by smell, and will attack prey that isn’t moving as long as it can detect its odor.

A Spray Gun Behind Each Eye Large parotoid glands behind the eyes and rows of poison glands down the body secrete neurotoxins, and the two major alkaloids in the skin secretion are samandarine and samandarone. Instead of relying on escape, the salamander is capable of actively spraying these chemicals at predators to discourage an attack.

Chemistry the Color Doesn’t Explain

Alkaloid synthesis appears to take place in the liver, testes and ovaries as well, while the larvae are entirely free of alkaloids. Fire salamanders are textbook examples of warning coloration, but a study of three populations in the Solling area of Lower Saxony, Germany found no correlation between how much yellow a salamander wore and the alkaloid content of its parotoid glands. The yellow varied with sex, males showing more, and with location.

Born Live, With Cannibalism in the Womb

The common mode is ovoviviparity: the female retains the developing eggs and later deposits many small larvae in water, usually already quite advanced. Some populations go further. Their females are viviparous, producing only a few large young that are fully metamorphosed at birth and nourished by the mother, and cannibalism inside the womb is one of the traits that characterize that derived strategy.

A New Fungus Arrives

In the Netherlands, at the edge of its range, the fire salamander was restricted to three small populations in the far south, and their numbers fell 96 percent from 2010, a decline its researchers could not pin on any known cause. In 2013, scientists isolated a new chytrid fungus, Batrachochytrium salamandrivorans, from a fire salamander population whose steep decline had brought the species to the edge of local extinction. It caused erosive skin disease and rapid death in fire salamanders infected in the lab. After it arrived in a Belgian population, two years of monitoring showed a rapid collapse with no sign of recovery, largely due to the survivors’ lack of added resistance and a demographic shift that prevented compensation for the deaths. The IUCN now lists the species as Vulnerable.