As a naturalist, I get asked about plants, mushrooms, etc. and whether or not they are poisonous or not. There’s an old wives’ tale about how indigenous people discovered whether certain plants were edible or not by watching wildlife. If you watch deer, rabbits, squirrels, etc. and the food they eat, you will see that they eat a lot of plants that are poisonous to humans, but do not affect them in the least bit. Deer, birds, and other critters eat poison ivy berries all the time, but please don’t think that just because they can certain things, it’s okay for us to do the same! For example, in the photo, a fox squirrel is eating a mushroom in the Amanita genus, which is extremely poisonous to us, but this and other species of mushrooms are a part of the squirrel’s diet. Trust me, they know what they’re doing!
Just like us, it has taken many, many years and trial and error for all of us to find out what we can and can’t eat, and it is the same for animals. Remember, they don’t normally have much of a choice of what they want to eat, so they have to adapt to the species of plants, mushrooms, etc. that are around them. Once they find this happy place, this is where they stay and it’s why you have a tendency to see certain animals associated with certain habitats. Pretty cool, huh?