When Arnold developed the concept and Ford upgraded the host software to include what Arnold referred to as "reveries" in an attempt to make his hosts seem more lifelike, part of Westworld's host population was largely unaffected by the mandatory software update. Reveries were developed in an effort for the hosts to begin acquiring a subconscious connection to old memories which would ultimately make it easier for them to improvise, but one population seemed to miss the update.
There are three categories of hosts in the park: engineers working upstairs, characters involved in the narratives, and animals. The animals were necessary additions to create a true illusion of the Wild West. The robot animals we've seen in Westworld include Ford's childhood pet greyhound, coyotes, owls, cattle, horses, rattlesnakes, and scorpions. There are also flies, which only seem to appear crawling across host eyeballs.
None of the animals in the park seem affected by the software upgrade. Had they been a part of the host revolution, we probably would have seen armies of bucking broncos, mad cows, attack owls, and an army of slithering snakes. Instead, the only animal that seems to have killed anything was Ford's greyhound, which supposedly killed a rabbit (according to young host Ford). In Episode 5, Ford tells Old Bill how his childhood pet greyhound killed a cat at a park. So perhaps he programmed his pet to follow through with that narrative.
So do the host animals have memory recall as well? When they get reset after a long day in the park of either watching lots of horrible deaths or experiencing their own deaths, do they have flashbacks like some of the human hosts do? How would PETA feel about the park?