They say you have to kiss a lot of frogs before you find the prince, but some female frogs are opting out. This post from thetinderblog explains how female frogs have found a way to exert control over their choice of mates. The post refers to a recent study by researchers at the Museum für Naturkunde in Berlin, Germany. They found that female frogs will often resort to extraordinary measures to avoid unwanted suitors, including faking their own deaths.
Explosive Breeding Behavior
Some frog and toad species are explosive breeders. This means they have short reproductive periods, requiring them to gather in large numbers to mate. Hundreds, possibly even thousands, of animals come together to breed for a few days to a few weeks, typically in the spring.
However, some females may take longer to mature and they do not breed every year. So males outnumber the females, leading to stiff competition for mates. A number of males will fight to cling to one female, forming a mating ball. However, the female frog will often drown as a result of their forced attention. It was previously thought that females were helpless against these unwanted advances, but researchers have discovered they are not without defenses.
Froggy Went a-Courtin’ and Got Rejected
One common behavior a female frog uses to reject a clingy male is to rotate her body on its axis. This shifts the male’s position so he is under the female, and consequently under water. The male may be forced to let go to escape drowning, plus it allows the female to breathe.
Another approach researchers observed was the use of vocalizations, or calls. In the mating frenzy, male frogs sometimes grab other males by mistake. When this happens, the male on the bottom uses what is referred to as a “release” call to let the male frog on top know he’s wasting his time. Female frogs mimic the male’s release call with a deep, low-frequency sound like a grunt. This lets the male know she’s not interested in mating. Females also voice their displeasure with a higher-pitched squeak.
Playing Dead Can Save Their Lives
The most extreme strategy scientists recorded was females pretending to be dead to discourage aggressive males. This is called tonic immobility. The female frogs stiffen their arms and legs and extend their limbs away from their bodies. Then, they wait motionless until the male frog releases them. Researchers believe tonic immobility is also a stress response, as the corticosterone in the frogs’ blood is positively correlated with the duration of their immobility.
Observation has shown remaining still is a better option than fighting off undesirable males. Any movement on the female’s part will draw the attention of more males, making the formation of a potentially deadly mating ball even more likely. Fortunately, the researchers found that avoidance behaviors are often successful. These strategies were typically used in combination, which resulted in the escape of 46% of female frogs in the study. Faking their own deaths may have saved their lives. Unfortunately, for some frog species such as Rhinella proboscidea, even death isn’t a deal-breaker.
