The practice of making animals fight each other remains a controversial topic today. Known as blood sports, these activities are illegal in many places but still permitted in some regions. A few centuries ago, they were widely accepted as a form of entertainment, and some animals were even bred specifically for such purposes.
Many animals went extinct as blood sports became largely outlawed, as they had no other purpose. However, some continue to survive and are still used in these cruel sports, while others are being bred for this very reason. Below are ten animals that were bred by humans for blood sports.
10. Cordoba Fighting Dog - Bred For: Dog Fighting

The Cordoba Fighting Dog was a now-extinct breed that was specifically bred for dog fighting. Originating from Cordoba, Argentina, this breed got its name from the region. It was believed to have been created by crossing Spanish fighting mastiffs and bulldogs with Bull Terriers. Highly valued by dog fighters for its speed and aggression, the Cordoba Fighting Dog would fight not only other dogs but even larger wild animals like pumas.
The Cordoba Fighting Dog was known for its extreme aggression. Male dogs were notorious for attacking and killing females during mating. The aggression wasn’t limited to other dogs—humans were also at risk, as the dogs were hostile toward people. While sometimes used for hunting, they were not kept in packs, as they preferred fighting over hunting. It was generally advised to pair only a male and female for hunting, though fights could still occur.
With a low reproductive rate and a high mortality rate due to their frequent deadly battles, the Cordoba Fighting Dog had a dwindling population. The breed eventually became extinct when dog fighting was banned.
9. Asil - Bred For: Cockfighting

The Asil (also known as Aseel) chicken is one of the oldest breeds bred specifically for cockfighting. Originating in India over 2,000 years ago, it has been refined over centuries. The Asil is known for its fierce fighting spirit. Through generations of selective breeding, it has developed powerful spurs that are perfect for cockfighting. Unlike other fighting chickens, the Asil doesn't use artificial spurs, relying instead on its natural spurs covered in tape.
Asil chickens are characterized by their strong legs, beaks, bones, and thick necks. They are incredibly aggressive, often fighting for days without giving up. They are also relatively heavy, with the average Asil cock weighing between 1.8 and 2.7 kilograms (4–6 lb). This makes them formidable fighters, although their weight also slows them down. Even as young birds, Asils display the same aggression as adults, instinctively engaging in mock fights from just a few weeks old.
8. Lusitano - Bred For: Bullfighting

An interesting aspect of Spanish bullfighting is the involvement of a matador known as a picador, who rides a horse and uses a pike to wound the bull's neck, weakening it for the kill. Most bulls are killed in the end, although in rare cases, a particularly impressive bull may be spared. The Lusitano horse is one of the few breeds used by the picador in this traditional fight.
Sometimes, Lusitano horses are blindfolded to prevent them from seeing the bull, while other times they are not, and they must skillfully avoid the bull’s horns as the picador attempts to strike it. These horses are prized for their bravery, composure, and agility. Unlike other horses, they do not shy away from the bull and may even charge toward it.
Cagancho is a renowned Lusitano horse. Over an illustrious 11-year career, he fought in more than 1,000 bullfights across Spain, Portugal, Mexico, and France. Typically, horses are euthanized once they grow too old for the ring, but Cagancho was an exception. He was spared and allowed to retire in 2002, living until his death from a stroke in 2015.
7. Betta - Bred For: Fish Fighting

The Betta fish, often referred to as the Siamese fighting fish, was bred for combat in Siam (modern-day Thailand). Its name comes from the Bettah, a warrior tribe. Bettas have been bred for fish fighting since the 1800s, when the people of Siam discovered the fish's tendency to fight when placed together. These fights would usually last only a few minutes until one fish retreated, but over time, the fish were specifically bred for these battles.
Initially, the fish fought until a winner emerged, usually the larger fish. The victorious fish would be removed for healing and then pitted against other champions. What started as brief skirmishes gradually became intense battles that could last for hours. In these matches, the winner was determined not by the degree of injury, but by the fish's determination to stay in the fight while the defeated one withdrew.
In the past, substantial wagers were placed on Betta fish fights. These bets ranged from money to homes, and in some cases, even family members. Some men even gambled their wives. Betta fighting became so popular in Siam that the king eventually started issuing licenses for the fish. Although these fish are still bred and used for fighting today, it's common for the fighters to be discarded after the bouts.
6. Bull and Terrier - Bred For: Dog Fighting

The Bull and Terrier, often confused with the Bull Terrier, was a fighting dog bred by crossing a bulldog with a terrier. It is the ancestor of the modern Bull Terrier, among other breeds. Dog fighting became the sport of choice after bullbaiting was outlawed in England in 1835. Breeders sought to create a fast, lightweight dog that could withstand prolonged fights, as dog fighting typically lasted longer than bullbaiting. Additionally, the dog needed to be small enough to hide in case the police arrived at the scene.
To achieve this, breeders crossed the Olde Type Bulldog with various terriers, resulting in a dog that was as quick and alert as the terrier but possessed the bulldog's strength and high pain tolerance. These dogs fought to the death. In 1850, James Hink crossbred the Bull and Terrier with other dogs to create the Bull Terrier. Unlike its predecessor, the Bull Terrier featured a longer head and no bow legs. Before being named the Bull Terrier, it was known by other names, including the Hinks Breed and the White Cavalier.
5. Samurai Spiders - Bred For: Spider Battles

Every June, the people of Kajiki, Kagoshima, Japan, hold spider battles known as kumo gassen. These battles, which have been a tradition for over 400 years, feature two female Argiope amoena spiders, also known as samurai spiders, fighting each other. In preparation, participants either catch or purchase spiders and begin training them for the contest.
The spiders do not fight to the death, and a human referee is always present to separate the creatures if the battle becomes too chaotic. A spider can win in one of three ways: by biting first, by trapping its opponent in its web, or by destroying the rival’s web. The first spider battle is thought to have been organized by the Japanese military leader Shimazu Yoshihiro to boost the spirits of his troops.
4. Miura - Bred For: Bullfighting

Miura bulls are among the most formidable Spanish fighting bulls. They are bred on a cattle ranch in Seville, Spain, once owned by Don Eduardo Miura Fernandez, who is credited as the first person to breed them, which is why the bulls bear his name. The first Miura bull entered the bullring on April 30, 1849.
Miura bulls are renowned for their massive size and fierce temperament. Some of these bulls have even achieved fame in the ring.
One legendary bull, Murcielago, survived 24 stabbings from a picador in 1879, yet was spared. Other bulls, like Reventon and Islero, killed bullfighters during the fights. The Miura bulls also inspired the name of the iconic Lamborghini cars, with some claiming that Ferruccio Lamborghini designed his famous logo after visiting the Miura ranch.
3. Old English Bulldog - Bred For: Bullbaiting

The Old English Bulldog was originally bred for the brutal sport of bullbaiting, and its name, 'bulldog,' reflects this purpose. In these contests, a pack of bulldogs was released to engage a tethered bull. The victor was the dog that could latch onto the bull's nose and pin it down. These bullfights were often bloody, and it was common for the bull to injure or kill the dogs in the process.
When bullbaiting was banned in England in 1835, the Old English Bulldog faced extinction. However, some were brought to the United States, where they were used to subdue wild bulls by gripping their noses until a rope was secured around the bull’s neck. Over time, the Old English Bulldog was crossbred with pugs to create the Olde English Bullogge. Unlike its predecessor, the Bullogge has a smaller build and mouth, making it ill-suited for the rough nature of bull encounters.
2. Lottatore Brindisino - Bred For: Dog Fighting

Also known as the Brindisi Wrestler Dog, the Lottatore Brindisino is a relatively new breed developed in Brindisi, Italy. This breed was created by crossbreeding Pit Bulls with Cane Corsos and Rottweilers, and is believed to be descended from dogs that had previously triumphed in dogfights. However, the breed is not yet fully standardized, with different breeders putting their own spin on its characteristics.
In Italy, the Lottatore Brindisino is primarily used by the local mafia for dog fighting, though it also serves as a guard dog in some cases. This breed is known for its aggression and is extremely difficult to manage. While it may show affection toward its owner, it tends to be hostile toward strangers, both human and canine.
1. Kelso - Bred For: Cockfighting

Kelso cocks are a breed of fighting chickens originally developed by Walter Kelso. He created the gene pool by purchasing victorious cocks from fights and crossbreeding them with various hens. This was during a time when most breeders adhered to maintaining pure breeds, believing them to be superior for cockfighting. However, Kelso preferred to focus on crossbreeding to improve the strength and fighting abilities of his birds.
Whenever Kelso acquired a new cock, he would pair it with the sister of one of his winning birds. If the new cock proved to be a successful fighter, he would keep its sisters and continue to crossbreed them with any future acquisitions. After the death of his friend and fellow breeder, John Madigen, in 1942, Kelso and another breeder, Bill Japhet, inherited Madigen's cocks and crossbred them with their own stock.
Today, the Kelso cock has developed into several subbreeds. In the Philippines, one of the most notable is the Firebird Kelso, bred by Sir Biboy Enriquez, who is widely known as 'the Kelso Man of the Philippines.' Other variations include the Dink Kelso and the Out and Out Kelso.
