- Who
- Alpine salamander, Salamandra atra, Common frilled shark, Chlamydoselachus anguineus
- What
- 4–5 year(s)
- Where
- Not Applicable ()
The longest-known gestation period in the animal kingdom is four or five years for the alpine salamander (Salamandra atra), native to the Swiss Alps. While two to three years is the more typical length of pregnancy for this mountain-dwelling newt (still a record among amphibians), at the higher elevations of their range, gestation extends up to four years (1,700 m+) or even in excess of five years (2,500 m+). A rival contender for this title is the common frilled shark (Chlamydoselachus anguineus), an extremely primitive species of elasmobranch native to all oceans with a gestation of at least 3.5 years.
The pregnancy of the alpine salamander is five to six times longer than that of humans. They are unusual among their kind as they give birth to live young, rather than laying eggs, a trait shared with the closely related fire salamander (S. salamandra).
Among mammals, the current record holder is the Asian elephant (Elephas maximus), with an average gestation period of 650 days (over 21 months) and a maximum of 760 days (over 2 years) – more than two and a half times that of humans. However in July 2023, a paper published in the journal Royal Society Open Science posited that the baleen whale (Balaena mysticetus) may take this crown, with a potential gestation of 23.6 ± 1.50 months, but farther research is needed before this can be fully confirmed.
On a similar note, the longest egg-brooding period ever recorded is a continuous 53 months (almost four-and-a-half years) by a female deep-sea octopus belonging to the species Graneledone boreopacifica observed in the Monterey Canyon via remote-controlled viewing apparatus by California's Monterey Bay Aquarium Research Institute during 2007–2011.
