Contrary to the conventional notion that female frogs simply submit to the desires of persistent males, a new study reveals that they frequently fake their own deaths to evade their amorous pursuers.
The research challenges the traditional perception of female European common frogs (Rana temporaria) during mating season as passive participants in the breeding process, particularly in the context of explosive breeding, a common strategy among frogs. During this intense mating season, where numerous males compete for individual females, “mating balls” are known to form, with several males enveloping a single female.
PHYSICAL EXHAUSTION AND EVEN LIFE-THREATENING SITUATIONS
Amidst this tight breeding schedule, female frogs face physical exhaustion and even life-threatening situations. When caught in a mating ball, they seemingly struggle to shake off unwanted suitors, and these encounters can lead to drowning. However, female European common frogs have developed several defense mechanisms, discovered accidentally by researchers conducting experiments to explore male preferences for female body size.
ROTATING BODIES
While the study didn’t reveal any particular size preferences among males, it did uncover intriguing avoidance behaviors exhibited by females. The researchers observed three primary avoidance behaviors: “rotation,” “release calls,” and “tonic immobility” (feigning death).
Among these, rotating their bodies was a prevalent technique used by 83 percent of clasped females. This action might serve to assess the strength and endurance of their male suitors or make males more susceptible to drowning. Nearly half of the female frogs, 48 percent, resorted to release calls, an ingenious strategy that involved mimicking male frog calls to deceive males into releasing them. Approximately 33 percent adopted the tactic of playing dead, exhibiting tonic immobility, with outstretched limbs becoming stiff and showing no reaction to male attention.
Ultimately, 25 female frogs managed to escape their male counterparts. Smaller females were more likely to engage in escape behavior, and success was more common among smaller females who employed these strategies.
REPRODUCTIVE STRATEGIES
This study casts a new light on the reproductive strategies of common frogs and other species that employ similar methods. The authors suggest that tonic immobility might be a more viable option for females than engaging in physical confrontations because any movement in a large mating group attracts further male attention, increasing the chances of a mating ball forming.
The study acknowledges that the experiments may not fully reflect how these behaviors manifest in the wild. Nevertheless, gaining a deeper understanding of these frog behaviors can aid in their conservation efforts, particularly given the threat to many amphibian species. For instance, knowledge of female frogs’ inclination to play dead in unfamiliar environments can guide ecologists in preserving safe and familiar breeding grounds, ultimately contributing to the protection of these unique amphibians.
This research, published in Royal Society Open Science, opens a fascinating window into the world of frog behavior, offering insights that could inform conservation strategies for these intriguing and resilient creatures.
