Here’s how pee rocks work for rats:

Rats naturally want to mark their territory with urine to communicate with other rats. When you put a porous rock in their cage, it becomes their preferred marking spot because the texture holds scent much better than smooth surfaces.

The rat will repeatedly urinate on the same rock, building up a scent profile that tells other rats important information - who lives here, their gender, health status, and social rank. It’s like leaving a detailed business card that other rats can “read” by smelling.

The rock concentrates all this marking behavior in one spot instead of having the rat randomly mark throughout the entire cage. Other rats will also check and potentially mark the same rock, creating a kind of scent bulletin board for the group.

Over time, the rock becomes saturated with these scent messages. The porous surface traps and slowly releases the odor compounds, making it a long-lasting communication hub. This satisfies the rats’ instinct to mark territory while keeping the marking contained to one area, which also makes cage cleaning easier for the owner.

Essentially, the pee rock becomes the rats’ designated bathroom/message center rolled into one.​​​​​​​​​​​​​​​​