I have had similar experiences!
I generally convince myself thats its just my altered mind that makes me think the animals are weird. Sometimes, however, that just dosen't seem to add up. I'm not sure that any of this can be quantified or proven but I'll share my most interesting story anyway.
Cats seem to be the most commmon pet to react to altered states but my experience happened with a family of ducks.
After taking some LSD me and a few friends went for a walk along the lake. Walking along the beach we came upon a seagull. It did not fly away as we got closer but instead just walked a mere 3 feet infront of us for a good 50 yards before turning and walking into the woods. This seemed very very strange to me but I thought the bird may have just been injured.
We got to the place on the beach we were walkng to and right as we came through a clearing we saw a duck. A female mallard standing by herself on a rock. As we approached the duck stayed completely calm and did not move at all. One of my friends walked over to it and, to my astonishment, picked up the duck and started petting its head! I was stunned. My friends claimed she just loved animals and is friedly with them all but admits she has never picked up a wild animal before or since.
Again this duck could have been sick but then something even more surprising happened. As she sets the duck down and it slides into the water about 6 baby ducks swim out from behind a rock. The mom, still calm as can be, leads her babies across a tide pool and off into the woods. My jaw was on the floor and I still have no idea how this could have happened. Generally mother animals are very territorial and aggressive. We have been attacked for just walking near nests.
It was an amazing experience and I'm glad other people are having strange run-ins with animals as well. Thanks for bringing it up and reminding me of this experience! Sorry I have no scientific explanation and hardly even a personal one, but I would love to hear other peoples insight!
โHow long will this last, this delicious feeling of being alive, of having penetrated the veil which hides beauty and the wonders of celestial vistas? It doesn't matter, as there can be nothing but gratitude for even a glimpse of what exists for those who can become open to it.โ
โ Alexander Shulgin, Pihkal: A Chemical Love Story