Crows can recognize geometric regularity

How comparable is the intelligence of crows, dolphins, octopi and non human apes? Somewhat or not at all? There seem to be a host of things that each of those can do. Can apes do all of those things and the other groups just a few things each? Is there a huge leap of separation or does the leap come between us and them? Is it in any way quantifiable?

A lot of it comes from communication. We don't know how intelligent some of these things are simply because we can't communicate with them.

For apes and gorillas we can communicate. We've taught them sign language so we know hands down in terms of language we beat them. But for dolphins and octopi, we just don't really know.

We have not taught apes sign language. They can learn and form crude signs and use them to respond to stimuli or for rewards (wanting an orange, for example) but they’re not meaningfully communicating. It’d be like me claiming I taught my dog English because he can press the little button that plays a sound of me saying “biscuit!” when he wants a treat (which you have to take away from him because he will just mash it, since dogs want dog biscuits).

I think it's hard to define what meaningful communication is, exactly. By your standards, anybody who has worked a cash register would argue that a notable percentage of customers don't and perhaps can't meaningfully communicate.