system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Animal perception of humans.

Is there anything understood not just how our pets see us but perhaps even seals(that let us pet them wild) or octopi that interact with us without fear. Deer usually are pretty skittish around humans. To insects I assume we are just another giant.

Animals clearly see us differently but how do they see us, as just another random animal that is on a survival cycle. Can they make sense of any of our gestures like "come here" or petting them?
gpt
Animal behaviour is typically learned, but it can be genetic too. Any animal that isn't fearful either hasn't noticed you or is curious. Curiosity is a useful trait in nature because it can help us, and animals, learn new things, and the more you know, the less likely you are to die. If an animal is curious, it will approach you or act interested in you. When it does this its often sizing you up, figuring out how you tick, learning your weaknesses. It knows where you live. Joking aside, it's figuring out what a human is. This is often a behaviour found in animals that don't have many natural predators who can afford to be curious. An animal that is fearful may have a learned fear of humans, perhaps it's met some before and had a bad experience, or it has a lot of natural predators so it has a better chance of surviving if it stays away. To insects, we're a source of food or something to be ignored. Insects have relatively primitive brains but they do know that being dead = bad so they still avoid your flyswatter. So much. They avoid it so much. Those winged bastards. 

Whether or not an animal can make sense of gestures depends on how socially intelligent the animal is. Most gestures will need to be taught though. Animals mostly learn through association. They associate certain behaviours with certain rewards or punishments which is why the way to teach an animal something is through repetition. If you're interested, theres loads and loads of studies on the psychology of monkeys and apes who do ridiculously cool stuff. A monkey for example will only steal from you when it knows you can't see it which means it has a perception of what other creatures are doing and perhaps even why they're doing it. That may not sound like a big deal but it really is. But back to gestures. If you make a gesture at an animal, it will only respond to the gesture if it has associated a reward or punishment with that gesture. If zookeepers often use a "come here" gesture to signify that food has arrived, they will respond to "come here" when you do it too because it will make them expect food. See pavlov's dog. More intelligent animals are capable of discerning between different humans though.