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Amphibians are defined by their ability to survive on land and in water. In almost all cases, amphibians lay their eggs in water, where they are protected from land-based predators. Frogs, toads, newts and amphibious salamanders display common courtship rituals. A number of factors determine whether conditions are right for mating, and amphibians have a number of rituals to get the ball moving.
By the Water
One of the defining characteristics of amphibians is that they reproduce by or in water and lay their eggs by or in water. Amphibians are superficially similar to reptiles, but this habit of breeding by water is a key distinction. In the majority of cases, amphibians choose to mate in or by still or static waters so the eggs they lay can remain undisturbed by water currents.
In all cases, male limbed amphibians clasp the female from behind in what is called amplexus. From here, he will attempt to penetrate her in order to fertilize her eggs. Amphibians may remain in amplexus for hours or, in the case of frogs and toads, sometimes days.
Color and Size
Female frogs have been recorded displaying color discrimination during courtship. They respond more favorably to mating calls from frogs that closely match their own coloration. Males favor larger females and will always seek to reproduce with the largest available. This frequently results in male frogs and toads entering amplexus with entirely the wrong species of female.
Lack of Discernment
The drive to find the largest female can cause male frogs and toads to not only attempt to mate with the wrong species, but it also drives them to attempt copulation with the wrong animal altogether. In fact, males will sometimes attempt copulation with inanimate objects and will remain in a state of failed amplexus for hours.
Under a Full Moon
All amphibians reproduce under moonlight. They use the lunar cycle to coordinate their gatherings at ponds. This coordinated gathering reduces the amphibians exposure to threats and greatly minimizes their chances of being eaten.
Estrogen and Rasping
Bizarrely, the female hormone estrogen actually reduces a male’s state of arousal. Male frogs exposed to varying concentrations of estrogen during a study at the Center for Molecular Medicine in Germany produced sexual calls with lower frequency and produced rasping, indicative of low sexual arousal, more frequently.
- Animal Planet: Frog
- All About Frogs: The Life Cycle of a Frog
- Pub Med: Amphibian Amplexus in Microgravity
- Pub Med: Visual Mate Choice in Poison Frogs
- Environmental Graffiti: The Most Bizarre Mating Rituals in the Animal Kingdom
- BBC Earth News: Amphibians Mate under a Full Moon
- Plosone: Estrogens Can Disrupt Amphibian Mating Behavior
- Image courtesy of Compfight.com