It owes its name not to its presence, but to its shape at low tide. In fact, the islet, which is linked to Îlet à Eau by an arm of land, looks like a rat with a tail.
It is surrounded by highly eroded cliffs. Due to its low altitude, it is subject to a strong marine influence.
Although uninhabited, Îlet aux Rats has a single dwelling, most likely an old second home.
Along with Îlet à Eau, it is one of the few islets that is not a protected site.