We have read in the books that a female reproduces without having sex. It is next to impossible in humans and even in animals but there is a rare species that reproduces without the mates touching each other. Meet the Bombay night frog, an oddity in the anuran world that reproduces without the mates touching each other. Scientists have been watching randy male Bombay night frogs, found in India and when they witnessed the amphibians performing the ‘dorsal straddle’.
These frogs can fertilise a female’s eggs without making contact at the same time by leaving their sperm trickling down the female’s back.
The ‘frogs’ world is very complex and there are 7000 species. Researchers led by Delhi University professor S D Bihu have found that the Bombay night frog adopts a seventh distinct position.
Called dorsal (back) straddle. It has the male spreading itself over the female’s back with its feet clutching or resting over leaves and twigs on the sides. Bihu said the male appears to release sperm over the female’s back and then moves away.
After that, the female lays her eggs, which are fertilised by the sperm. In other frog species, females usually lay eggs during amplexus and males simultaneously release sperms to fertilise them.
“This is a frog with a remarkable reproductive behaviour, and this discovery is fundamental to understanding the evolutionary ecology and behaviour in anuran amphibians,“ said Bihu.
Bombay night frogs are found mainly near fast-flowing streams in the Western Ghats. They are classified as an ancient group of frogs that diversified 7080 million years ago. In the breeding season, they can be seen calling from the ground and over hanging vegetation in large numbers, soon after sunset.
The species also shows other rare sexual traits. For instance, the female, as also the male, croaks the mating call during breeding season, a behaviour seen in only 25 species worldwide. Fights between competing males are also common, and last until the intruder is thrown out.
The research team also observed eggs of Bombay night frog being eaten by snakes. It’s the first documented observation of snakes eating frog eggs in India.
The research team comprising scientists from University of Delhi, National Centre for Biological Sciences, Bengaluru, and University of Minnesota, USA, observed the frogs in the field for 40 nights during monsoon months between 2010 and 2012.