Cockroaches are extremely successful in evolutionary terms -- they have been around for 300 million years. Cockroaches have survived multiple mass extinctions and have been eaten and squished by all kinds of critters, from amphibians to dinosaurs to mammoths. The cockroach is still around. Most of their predators/squishers are not. The evolutionary success champion is the cyanobacteria. There are still a few anerobic bacteria around, but the cyanobacteria killed most of them off emitting an incredibly toxic gas. The cyanobacteria remain today one of the major producers of this toxic gas. The cyanobacteria make cockroaches look like newcomers -- they have been around for 3.5 billion years. Intelligence has nothing to do with the success of cockroaches and cyanobacteria.