Image: Emanuele Biggi

Some tarantulas and frogs seem to have an interesting relationship – the unlikely pair sometimes co-exist in shared living arrangements.

Measuring hardly more than half an inch in length, microhylids might seem like a pretty insignificant family of frogs. But they’ve crossed onto scientific radars in a big way. Many of these tiny, narrow-mouthed frogs have been observed in Sri Lanka, Peru, and India living in close proximity to tarantulas.

Although the spiders are completely capable of killing and eating frogs of this small size, they instead seem to tolerate their existence. Why? For one, the frogs likely possess skin toxins that make them taste terrible to the tarantulas, but there’s probably more at play here.

Image: Emanuele Biggi

The answers aren’t definitive, but some research indicates that the frogs may benefit from these unique living arrangements in the form of protection and food. The relatively large spiders could be serving as a sort of bodyguard for the helpless amphibians, protecting them from snakes and other predators. Additionally, the frogs may eat the small invertebrates attracted to the spider’s prey remains.

In this case, their relationship would be a kind of commensal symbiosis where one party (the frog) benefits, but the other (the tarantula) isn’t affected either way. But the spider-frog relationship could also be an example of mutualism, with both benefiting in some way.

Remember those small invertebrates that are attracted to the remains of the spider’s prey? Well, they can also target the spider’s eggs — unless the frogs wipe them out first.

Giant tarantulas employ tiny frogs as housekeepers

The relationship may be more commonly occurring than we’ve realized so far. In fact, there could be frogs with their own “pet” tarantulas yet to be discovered living all around the globe.

You can read more about the phenomenon in this study.