From being too tired to having a headache, women are known to use a range of excuses to avoid sex.
Now, a study has shown that female frogs use even more extreme tactics when they’re not in the mood.
Researchers from the Leibniz Institute for Evolution and Biodiversity Science found that female European common frogs will roll and grunt when approached by an unwanted mate.
Meanwhile, a third of females will even fake their own death to avoid males who don’t take their fancy.
While previous studies suggested that female frogs were pretty passive, the findings indicate they play a much more active part in mate selection.
Researchers from the Leibniz Institute for Evolution and Biodiversity Science found that female European common frogs will roll and grunt when approached an unwanted mate.
Common frogs are ‘explosive’ breeders, meaning they have a very short breeding season taking place between a few days and two weeks.
Speaking to MailOnline, Dr Carolin Dittrich, lead author of the study, explained: ‘Hundreds of individuals gather at the pond at this time. The males fight for access to the females, which are usually the rarer sex in these breeding aggregations.
‘The males don’t seem to be very selective, at least in terms of female body size, and will randomly grab other individuals, even males or other species.
‘This behaviour leads to the formation of so-called mating balls, where several males can cling to one female, which can lead to the death of the female.’
In the study, the team set out to understand how the females avoid being crushed to death or drowned by the swarming males.
During observation of 54 frogs in water-filled tanks, the researchers found that 83 per cent of the females rolled onto their backs when grasped by males.
This could be to force the male under water, threatening to drown them if they do not release, according to the scientists.
Meanwhile, 48 per cent emitted grunts that mimic the ‘release calls’ made by male frogs to ward off other males.
Dr Dittritch believes that the frogs playing dead might be related to levels of stress experienced by young females.
Tonic immobility, the scientific term for death feigning, was more common among smaller and younger females while the older, larger frogs were more likely to use mimicked calls.
Dr Dittritch said: ‘The European common frog, females can only increase their reproductive fitness by participating in mating over several breeding seasons, so the selective pressure to survive the breeding season may be stronger.
![During observation of 54 frogs in water-filled tanks, the researchers found that 83 per cent of the females rolled onto their backs when grasped by males](https://i.dailymail.co.uk/1s/2023/10/11/14/76428077-12618573-image-a-24_1697030271523.jpg)
During observation of 54 frogs in water-filled tanks, the researchers found that 83 per cent of the females rolled onto their backs when grasped by males
‘We think that these mate avoidance strategies are due to a stress response that females experience during this time.
‘It may be that younger females are less experienced and the strong stimulus of males clinging to them leads to the tonic immobility we observed more often in smaller females.’
The research also suggests that females might be selecting the strongest males to mate with, with the rolling strategy used to test the strength and endurance of males.
Mating with a stronger male may also improve the female’s chances of survival as a strong male can kick off other competitors and prevent a mating ball from crushing her.
In several species, death feigning can be a strategy to avoid predators as the animal fakes its death to remain perfectly still when threatened.
However, death feigning as a mating avoidance strategy is much rarer and has only been observed in a few animals such as some spiders and dragonflies.
In 2017, ecologist Rassim Khelifa observed that female dragonflies that had already laid their eggs would crash to the ground and play dead if approached by a male.
Out of the 35 dragonflies Mr Khelifa observed, 27 dropped to the floor when pursued by a male with 21 escaping successfully.
On the other hand, among the gift-giving spider Pisaura mirabilis, it is the males who fake their death during sex.
Female gift-giving spiders will often consume their partners, so when threatened the male will sometimes ‘drop dead’, only cautiously coming back to life when it is no longer at risk of being consumed.
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Read more at DailyMail.co.uk