All I've heard from the various ex-insiders is that some are humanoid, some aren't. You're going into a interesting area but extremely difficult for a lot of us. For example, I personally believe an intelligent third party of some kind had a hand in our species' creation and early development. Because of that, I have no idea how intelligent life on other planets would have started.
You have to either adapted techniques or physical attributes to survive, as all animals we see have some ability to adapt. We observe animals adopting
strategies, developing weapons, or turning elements in their environment into weapons.
An aspect of nature I have always enjoyed is the ability of animals to communicate with each other and, brace yourself, reason. One example I found
through my own observations is when a squirrel spent a few minutes on our property tinkering with a squirrel-proof feeder. He examined the mechanisms
and setup for a bit, and then left and went up the tree. He got his friend who was higher up in the tree, who immediately followed him back down and
held the feeder in place, so it wouldn't move, while the first squirrel disassembled one of the mechanisms and got the bird seed out.
Honestly, the more you deeply observe and analyze, simply pay attention to the world around you, it will sometimes bring tears to your eyes when you
realize all the details and depth you can spend nearly a whole lifetime up to that point missing. It all adds to the understanding of the topic
you've brought up, I've found.
You know, the greys frequently take credit for the development of our species. The implications of that, as a truth or as a lie, blow my mind.