Let me elaborate, how likely is that there’s an animal on earth that’s smarter than us? By smarter, I understand intelligence is a nuanced topic unique to different animals, so for the sake of argument, let’s talk about, mathematics, critical thinking about where and how to apply those mathematical concepts, and creativity in any form.
Mathematics is a terrible baseline for intelligence since it has so many prerequisites for it to exist at the most basic level.
We very often misunderstand the reason of our success as a species to be exclusively because of our unique intelligence alone, when it’s really the special combination we have that has allowed that intelligence to be useful.
Being really good at communicating and creating languages for example, being a land based species, having fingers that we can use with a lot of ease into creating tools, being worse predators physically which gives a material reason for us to create those tools initially, intelligence alone would be a small thing without them.
As others have said, scientists believe that several species are even more intelligent than humans, but maybe they never needed our way of life and natural selection never led them to it because they were just fine as they were.