Rat poop on the wall . . . not at all

What would you rather have in your house, rats or lizards? We were warned that in case a schiera—houses attached to each other—rats could easily find a way to move from one attic to the next. Before we remodeled our attic in 2017 and 2018, we saw ample evidence that rodents had made themselves at home there, but each year I added more barriers. I sprayed foam insulation or stuffed steel wool in every possible gap, but I still found rat droppings each time we returned, even though I’ve never in my nine years actually witnessed an offender.

Found on our wall . . .

I had hoped that this fall would be the exception, because in the spring I had plugged even the tiniest of holes—or so I thought. But once more, around the walls of the attic, I saw the characteristic pellets. But wait, why were two of them stuck to the smooth sheetrock wall? A close-up examination and a quick web search revealed the answer: We don’t have rats in the attic; we have wall geckos! They are the source of the droppings, not rats, as the images clearly show.

According to pest control experts and lizard specialists, geckos are much preferrable to rats. Though there are some internet posts about the dangers of geckos, the scientific information I found says these claims are false, and the truth is that geckos pose no threat to people.

Dr. Jeanne Tarrant of the Endangered Wildlife Trust in South Africa, said in an email to a French news agency that geckos are not harmful to humans and “actually provide a service by eating insects and spiders around your house.”

“Humans and house geckos have been living alongside each other for hundreds if not thousands of years, with no detriment to humans,” she wrote. “It really would not be recommended to try to eliminate them from your home.”

Professor Aaron M. Bauer, a biodiversity specialist at Villanova University in Pennsylvania and a world authority on geckos—he even has a species named after him—echoed Tarrant’s comments.

Biting, he said, is highly unusual in geckos and, in any event, you’d receive nothing more than an unpainful nip on the off chance you try to handle one. 

Salmonella transmission is similarly unlikely, he explained: “Geckos, like many reptiles, can carry salmonella although such transmission is not common, and it is easily avoided. Geckos are probably less likely to transmit salmonella than other reptiles that have larger, wetter fecal material.”

On the other hand, rat poop is much more dangerous. Web MD says: “Because contact with rat poop and pee can lead to dangerous and life-threatening infections, use extreme caution when cleaning. Inhaling particles from rat droppings can cause diseases like hantavirus, so be very careful not to clean up the droppings in a way that kicks up dust, like sweeping or vacuuming.”

How the geckos get in the attic and why they are always gone when we arrive is still a mystery, but an obvious part of the answer is their small size and streamlined shape. I’ll probably never be able to keep them out, but their presence probably explains why we have so few spiders and other bugs. Since they live primarily on the walls, cleaning up after them just means running the vacuum cleaner hose around the baseboard each time we return, not a bad trade-off for the organic pest control services they provide. And incomparably better than rats.