Not fully, but we know it requires a minimum amount of activity in the brains of vertabrates, and at least observable in some large invertebrates.

I’m vastly oversimplifying and I’m not an expert, but essentially all consciousness is, is an automatic processing state of all present stimulation in a creatures environment that allows it to react to new information in a probably survivable way, and allow it to react to it in the future with minor changes in the environment. Hence why you can scare an animal away from food while a threat is present, but you can’t scare away an insect.

It appears that the frequency of activity is related to the amount of information processed and held in memory. At a certain threshold of activity, most unfiltered stimulus is retained to form what we would call consciousness - in the form of maintaining sensory awareness and at least in humans, thought awareness. Below that threshold both short term and long term memory are impaired, and no response to stimulation occurs. Basic autonomic function is maintained, but severely impacted.

Viruses and prions: “Allow us to introduce ourselves”