Real animals!

An important distinction to note about live-action movies which incorporate real animals as characters is the fact that these animals are exactly that - real. This means that the animals portraying the character (and often there is more than one animal playing the same role) have to be specifically trained for 'acting' in the role. These animals are conditioned to react and respond to their environment in a certain way. Heidegger's essay in Animal Philosophy claims that while humans have recognition, animals merely have the ability to react - and that is what makes animals "poor in the world". But in these cases, when the animal is taught how to act on the camera, the animals - whether they are cats, dogs, gorillas or dolphins - they are then able to recognize their surroundings and commands as such. 

Jack the Monkey from Pirates of the Caribbean: Curse of the Black Pearl.
Played by two Capuchin monkeys in the movie; played by others in sequels.

It is interesting to note that humans are still in control - it is humans who have written the part the animals are to play, and humans who have trained the animals. The world within the movie belongs to the humans outside of it. Calarco explains that to "have" world, to be rich in it, is to construct and see a world that we can make or control. This is exactly what the humans have done in creating film.

Of course, there are movies that don't use real animals - directors make use of puppets such as Salem Saberhagen the cat from the TV series Sabrina the Teenage Witch and Falkor the dragon from The Neverending Story, or CGI animals like Rocket the raccoon from Marvel's Guardians of the Galaxy. These do not count as real animals, as they are created by humans working behind the scenes, and voiced by human actors. However, they are still important as part of our examination. These depictions, despite not being real animals, still reflect the human being's vision of animals used as sidekicks, similar to animals in animated films. 

A top 10 list of animal side-kicks in live action movies.
A couple of these animals, like Falkor and Rocket, are not real animals.