Animal abuse on the set of Hollywood movies has been a controversial topic for decades. Since 1939, the American Humane Association has monitored the treatment of animal actors on sets of thousands of films, giving most of them its famous seal of approval, stating that 'No animals were harmed' in the making of the movie.

The issue made national news again this week when video from the set of the upcoming film 'A Dog's Purpose' was released by TMZ, showing a frightened dog being forced to enter rushing water and being submerged before a crew member yelled 'Cut!'

The pigeons were shown a black-and-white photograph of a dog along with two icons—one that represented the word dog and the other that was randomly selected. If the pigeon pecked on the right.

After the video was released, People for the Ethical Treatment of Animals — which has argued for computer-animated animals to replace living animals in movies — called for a boycott of the movie, which is slated for release on Jan. 27. According to The Hollywood Reporter, Universal Pictures canceled the Los Angeles premiere of 'A Dog's Purpose' one day after the video surfaced.

'A Dog's Purpose' is just the latest movie to face claims of on-set animal abuse. Listed below are 10 other popular films that faced similar allegations in the past.

'Heaven's Gate' (1980)

Labeling 'Heaven's Gate' as 'popular' may be a stretch — it notoriously bombed at the box office — but it stands as perhaps the most notorious example of rampant on-set animal abuse. According to the American Humane Association and various reports, several animals were killed in brutal ways while making the film, including a horse that was 'blown up' with dynamite. Other animal abuse reports from 'Heaven's Gate' include real cockfights, horses being tripped, cattle being cut and chickens being decapitated.

'The Hobbit: An Unexpected Journey' (2012)

According to a massive 2013 investigation into the American Humane Association's practices by The Hollywood Reporter, 27 animals died on the set of the 2012 blockbuster 'The Hobbit: An Unexpected Journey.' The creatures, including sheep and goats, died of awful causes including dehydration, exhaustion and drowning. Despite the deaths, the American Humane Association didn't further investigate and eventually gave the movie a 'carefully worded' seal of approval, according to The Independent.

'Pirates of the Caribbean: The Curse of the Black Pearl' (2003)

One of Disney's most popular movies faced reports of animal abuse after The Hollywood Reporter looked into reported incidents during its filming. 'Many smaller animals' — including fish and squid — were killed after explosions were detonated in the ocean. 'No one thought they would result in disturbing the marine life, so no precautions were taken,' according to documents from the production of 'Pirates of the Caribbean: The Curse of the Black Pearl.' Dead marine life was seen 'washing up on shore' for four days following the shoot.

'The Adventures of Milo and Otis' (1986)

This sweet movie about a kitten and a pug who become friends was a favorite of many kids who grew up in the 1990s. 'The Adventures of Milo and Otis' was also looked upon controversially, based on reports of animal abuse while it was being filmed. According to a 1990 Australian newspaper report, more than 20 kittens were killed during its production and one cat's paw was intentionally broken to make it look unsteady when walking.

'Ben-Hur' (1959)

Upon its release, 'Ben-Hur' was a massive blockbuster that won 11 Oscars, which still stands as the highest tally in history. But according to film historians, as many as 100 horses were killed during the production of the iconic film. The second-unit director of 'Ben-Hur' reportedly ordered horses be shot and killed 'if they limped,' without seeking veterinary care.

'Stagecoach' (1939)

Western movies often use horses during action sequences, making them rife targets for potential animal abuse investigations. The critically beloved 1939 film 'Stagecoach' faced several claims due to the use of a controversial stunt device that has since been banned. According to the A.V. Club, the crew of 'Stagecoach' made use of a device that used wires attached to a horse's legs to 'yank' their legs out from under them as they ran, forcing them to violently fall. The device resulted in the deaths of several horses.

'Life of Pi' (2012)

Part of the aforementioned Hollywood Reporter investigation into Hollywood animal abuse focused on troubling incidents from the set of the Oscar-winning movie 'Life of Pi.' The film's co-star is a Bengal tiger and the real-life animal used in the movie was reportedly treated poorly on set — and his mistreatment was allegedly covered up by the American Humane Association. King, the real-life tiger used in the movie, nearly drowned during the shoot, according to people on set.

'First Blood' (1982)

The first Rambo movie presents a brutal depiction of combat violence but apparently some of the animals used during its filming were forced to endure real-life suffering on the set. American Humane Association accounts indicate rats were killed in various ways, including being 'burned by an actor' and being 'squeezed and hurled against a wall.' As a result, 'First Blood' was deemed 'Unacceptable' by the American Humane Association's ratings board.

'Speed Racer' (2008)

This live-action movie version of the classic cartoon 'Speed Racer' was dogged by PETA because of reports of animal abuse on set. People on set of the film claimed a chimpanzee actor used in the film was 'beaten' after it bit a human actor. The movie was deemed 'Unacceptable' by the American Humane Association as a result of the incident.

'Flicka' (2006)

Another heartwarming movie about an animal that ironically came under fire for unsafe practices was 'Flicka.' During the filming of this family movie, two horses were killed. The American Humane Association classified the deaths as 'unpreventable accidents,' but they obviously would not have happened had the horses never been used in filming in the first place. One horse was euthanized after breaking its leg during a scene and another broke its neck when it tripped on a rope while running.

Clint Davis covers entertainment and trending news topics for the Scripps National Desk. Follow him on Twitter @MrClintDavis.

Pigeons have better eyesight than humans do and have been trained by the US Coast Guard to spot orange life jackets of people lost at sea. They also carried messages for the US Army during World Wars I and II. (Credit: iStockphoto)

Pigeons can categorize and name both natural and human-made objects—and not just a few. The birds in a new study categorized 128 photographs into 16 categories.

The finding suggests a similarity between how pigeons learn the equivalent of words and the way children do, according to Ed Wasserman, professor of psychology at the University of Iowa and corresponding author of the study.

“Unlike prior attempts to teach words to primates, dogs, and parrots, we used neither elaborate shaping methods nor social cues,” Wasserman says of the study, which appears online in the journal Cognition. “And our pigeons were trained on all 16 categories simultaneously, a much closer analog of how children learn words and categories.”

For researchers like Wasserman, who has been studying animal intelligence for decades, this latest experiment is further proof that animals—whether primates, birds, or dogs—are smarter than once presumed and have more to teach scientists.

“It is certainly no simple task to investigate animal cognition; But, as our methods have improved, so too have our understanding and appreciation of animal intelligence,” he says.

“Differences between humans and animals must indeed exist: many are already known. But, they may be outnumbered by similarities. Our research on categorization in pigeons suggests that those similarities may even extend to how children learn words.”

Peck the symbol

Wasserman says the pigeon experiment comes from a project published in 1988 and featured in the New York Times in which University of Iowa researchers discovered pigeons could distinguish among four categories of objects.

This time, the researchers used a computerized version of the “name game” in which three pigeons were shown 128 black-and-white photos of objects from 16 basic categories: baby, bottle, cake, car, cracker, dog, duck, fish, flower, hat, key, pen, phone, plane, shoe, tree.

The birds then had to peck on one of two different symbols: the correct one for that photo and an incorrect one that was randomly chosen from one of the remaining 15 categories. The pigeons not only succeeded in learning the task, but they also reliably transferred the learning to four new photos from each of the 16 categories.

Smarter than your average bird

Pigeons have long been known to be smarter than your average bird—or many other animals, for that matter. Among their many talents, pigeons have a “homing instinct” that helps them find their way home from hundreds of miles away, even when blindfolded.

They have better eyesight than humans do and have been trained by the US Coast Guard to spot orange life jackets of people lost at sea. They carried messages for the US Army during World Wars I and II, saving lives and providing vital strategic information.

The researchers say their expanded experiment represents the first purely associative animal model that captures an essential ingredient of word learning—the many-to-many mapping between stimuli and responses.

“Ours is a computerized task that can be provided to any animal, it doesn’t have to be pigeons,” says psychologist Bob McMurray, a coauthor of the study. “These methods can be used with any type of animal that can interact with a computer screen.”

How children learn

McMurray says the research shows the mechanisms by which children learn words might not be unique to humans.

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“Children are confronted with an immense task of learning thousands of words without a lot of background knowledge to go on,” he says. “For a long time, people thought that such learning is special to humans. What this research shows is that the mechanisms by which children solve this huge problem may be mechanisms that are shared with many species.”

Wasserman acknowledges the recent pigeon study is not a direct analogue of word-learning in children and more work needs to be done. Nonetheless, the model used in the study could lead to a better understanding of the associative principles involved in children’s word learning.

“That’s the parallel that we’re pursuing,” he says, “but a single project—however innovative it may be—will not suffice to answer such a provocative question.”

National Institute of Mental Health, National Eye Institute, and National Institute of Deafness and Other Communication Disorders supported the research.

No Pigeons Were Harmed During The Making Of This Game Show

Source: University of Iowa