[Razengan]

One overriding question may be: Do they need to?

There are things that other animals can do which humans can't, such as an octopus communicating with a grouper fish, two entirely different species, by changing the color and patterns of their skin, to corral and trap a prey (as seen on a segment of BBC's Blue Planet.)

Are humans "dumber" if we use that objective criteria to compare intelligence?

[dahdum]

> Are humans "dumber" if we use that objective criteria to compare intelligence?

We have advanced communication with our domesticated animals, especially dogs. Also have some communication with non domesticated animals like primates, dolphins, etc..