Big Night (amphibians)

Big Night is an annual event common to amphibians as they emerge from underground hibernation in the spring, travel to vernal pools, and mate.

Background
Amphibians such as salamanders and frogs in a local area usually use the same overwintering area and the same breeding area, returning generation after generation to the area in which they were spawned. The breeding locations are areas where vernal pools develop from snowmelt and spring rains. The two locations can be a half-mile apart or even farther. Although referred to as the Big Night, the event for a species sometimes occurs on several occasions over days or weeks. In temperate areas, the event usually happens when temperatures are optimal for the particular species, after a rain. The salamander gathering for the mating ritual is known as congressing.

Human assistance
In some areas where the path of migration crosses a roadway, volunteers may assist the amphibians to cross the road safely. In some, amphibian and reptile tunnels have been built to funnel the migrating animals safely under the roadway.

In popular culture
Loren Eiseley wrote an essay, The Dance of the Frogs, about Big Night.