I’ve loved animal movies for as long as I can remember.

When I was a kid, I sat on the floor of my grandmother’s lounge room and watched The Adventures of Milo and Otis over and over again – completely perplexed as to how someone taught these animals to act.

How did they know the story? How did they understand where to go? How were they so… professional?

Of course, eventually I realised they weren’t actually acting. They’re animals – they’re just behaving out of instinct in response to the situations they’re placed in.

In the years since, I've consumed movies about animals without giving much thought to their experiences. I watched Air Bud, the entirely plausible story of a dog who's really, really good at basketball. I was completely obsessed with the pig in Babe, so much so that I was genuinely disappointed when I met an actual pig who was kind of... dirty. And not that friendly.

But recently, I joked with a friend about seeing A Dog's Purpose (less because I actually want to see it, and more because a movie has never been more explicitly targeted to my dog-loving sensibilities) and she stopped me. While I had heard the news stories about the treatment of dogs while filming A Dog's Purpose, I had purposely avoided reading them. I don't want to hear about people doing horrible things to a dog. It's disturbing.

But my friend had me stuck. She started describing in detail the sickening history of the treatment of animals on movie sets.

I should have known at the time, but Milo and Otis weren't played by one cat and one dog. They were played by dozens. Upon the release of  The Adventures of Milo and Otis, Animal Liberation Queensland founder Jacqui Kent came forward and alleged that more than 20 kittens were killed during filming. She also claimed a person on set had broken a cat's paw to make it look unsteady in a scene, and that one kitten fell off a cliff, while another scene saw producers make a pug fight a bear.

Many believed the film simply could not have been made without cruelty.

Now, 30 years later, leaked footage obtained by TMZ from the set of A Dog's Purpose shows animals are still distressed during filming.

In the video, a German Shepherd appears terrified as his handler tries to get him into a tank of flowing rapids. A man off-camera laughs and says, "you just got to throw him in. He's not going to calm down until he's in the water".

But the dog is desperately fighting not to be put in the raging waters. He tries to grasp the side of the tank so the current won't take him.

In the next clip, a dog struggles to keep his head above the water as the rapids hit the side of the pool.

Listen to the Mamamia Out Loud team discuss the culture of treating pets like your children. Post continues after audio. 

It's sickening to watch.

In the wake of severe criticism, the film's production company Amblin Entertainment released a statement about the incident.

"There were several days of rehearsal of the water scenes to ensure Hercules (the German Shepherd) was comfortable with all of the stunts," it read.

"On the day of the shoot, Hercules did not want to perform the stunt portrayed on the tape so the Amblin production team did not proceed with filming that shot.

"Hercules is happy and healthy."

An independent investigation found that "no animal abuse occurred on A Dog's Purpose set," but in that moment, clinging to the side of the tank, the dog looks scared. He has no way of understanding the rapids aren't real, and that he'll be watched closely and taken care of. He has no way of knowing it's all for a movie.

It's not hard to find similar examples in recent films. The tiger in The Life of Pi (many scenes were filmed using CGI, but a real tiger named King was used for select scenes) had a particularly frightening experience.

An email sent during production, and obtained by The Hollywood Reporter, read: "This one take with him just went really bad and he got lost trying to swim to the side. Damn near drowned."

Allegedly, King's trainer eventually attached a rope to him, and dragged him to the side of the tank where he could get out.

"I think this goes without saying but DON’T MENTION IT TO ANYONE, ESPECIALLY THE OFFICE!" the email continued.

"I have downplayed the f*** out of it."

While the American Humane Association (AHA) is responsible for monitoring animals in film, and holds the exclusive right to provide the 'No Animals Were Harmed' certification to a production, many believe it lacks integrity.

AHA representatives are required to be on set during films which involve animals, but in many cases, poor treatment of animals has gone unreported. An in-depth investigation resulted in allegations from AHA employees that "the organization distorts its film ratings, downplays or fails to publicly acknowledge harmful incidents and sometimes doesn’t seriously pursue investigations".

In fact, many films awarded with the 'No Animals Were Harmed' credit have had animals who were injured or killed during production.

For example, during filming for Pirates of the Caribbean: The Curse of the Black Pearl, dozens of sea life washed up on shore over several days after special effects explosions were set off in the ocean. A Husky dog was also repeatedly punched in the Disney movie Eight Below. 

Other productions such as Flicka, where two horses died during filming, receive the credit 'the American Humane Association monitored the animal action'.

While I've previously been appeased by such messages - it seems that shouldn't necessarily be the case.

Now when I see animals in movies or TV shows or even some advertisements, I feel sick. Unlike the actors alongside them, animals don't sign up for these roles. They likely can't distinguish between what is real and what isn't, and in order to get the emotional responses necessary for particular plot lines, they're intentionally put in a state of distress.

If a dog is scared and shaking and panicked on screen - it really is frightened. There is no pretending.

I just don't think our pursuit of entertainment is ever worth an animal's suffering.