I've noticed cats, dogs and my parrot acting strangely and out of character during psychedelic experiences. I'm sure they pick up on it, as much of the communication between ourselves and other species is non verbal, so any change in our behaviour, body language or size of pupils etc is very likely to be noticed by them and will alter their behaviour accordingly. I remember a house mate's dog, seeming to sense I was somewhere else after smoking 20x Salvia extract on LSD (one of my top 3 worst drug experiences ever) and the dog got up and came over to me and wagged her tail, looking up at me. It was the first thing in the real world I noticed, and helped ground me after what was a really hellish experience.