Tosa Inu: The Inu is a massive dog with some variations weighing anywhere between 130 to 200 lbs. and can reach heights of 24.5 to 32 inches. Originally bred to be a fighting dog, it is considered dangerous and legally restricted in some countries.

American Bandogge: This incredibly strong dog is a cross-breed between an American Pit Bull Terrier and a Neapolitan Mastiff. In spite of its muscular look, the dog was not originally bred for fighting. Nevertheless, some have used it as fighting dog.

Cane Corso: The Cane Corso is a well-muscled dog that can weigh anywhere between 99 to 150 pounds. The breed is known as a true and quite possibly the last of the coursing Mastiffs and is a descendant of the Canis Pugnax, which were dogs used by the Romans in warfare.

Bull Terrier: Known for their large, egg-shaped heads, Bull Terriers are exceptionally strong dogs with a #1 ranking in pound-for-pound lean muscle tissue. Though not particularly aggressive, the breed is known to have a strong “prey drive” which makes the Bull Terrier a dangerous dog towards smaller animals.

Rhodesian Ridgeback: Originally from Southern Africa, this dog is known for its ability to keep lions away from prey while the dog’s master makes the kill. This semi-domesticated, ridged hunting dog is loyal and intelligent, but is very aloof to strangers. They also require positive reward-training, avoidance of rough treatment and good socialization skills since they can be over-sensitive and may develop an aggressive side.

Dogo Argentino: The Dogo Argentino is a large, white, muscular dog that was developed in Argentina primarily for the purpose of big-game hunting, including wild boar and puma. Though extremely strong and athletic, the Dogo was bred to be non-aggressive towards humans. Nevertheless, it is illegal to own a Dogo in the United Kingdom under their Dangerous Dogs Act of 1991.

Boerboel: The Boerboel is a large, mastiff breed from South Africa that was bred for the purpose of guarding a home or farm. These dogs were often a first line of defense against predators and were valuable in tracking and holding down wounded game. Boreboels are loyal but very protective of their families.

Gull Dong: The Gull Dong (also known as the Pakistani Bull Dog) is a cross-breed between the Gull Tarrier and the Bully Kutta. Extremely strong and powerful, the Dong was specifically bred as a fighting dog and is known to be very aggressive and difficult to control

Basenji: A breed of hunting dog that originated from Central Africa, they have been classified as a sight hound. They exhibit alertness, curiosity and affection, though they are reserved with strangers. They are the 2nd least trainable of all dog breeds.

Perro de Presa Canario: The Perro de Presa Canario is a large dog that was originally bred for working livestock. The name of the breed is Spanish, and it means “Canarian catch dog.” Presas require early socialization and obedience training. In some situations, the Presa can be aggressive toward other dogs and suspicious of strangers.

Saint Bernard: The St. Bernard is a breed of very large working dog that originated from the Swiss and Italian Alps. Originally bred as a rescue dog, they have been made famous by tales of their gargantuan size and Alps rescue mission abilities. However, just like with other very large dogs, they must be trained to be sociable with strangers and other dogs during their infancy in order to prevent aggressive territorial behavior.

American Bulldog: The American Bulldog is a muscular, heavy dog. Though they are known for their pleasant and friendly demeanor, they can also exhibit the trait of ‘stubbornness’ as they are extremely confident. Originally this breed was bred as a working farm utility dog that could catch and hold wild boar and cattle, kill vermin, and guard an owner’s property.

Great Dane: Also known as the German Mastiff or Danish Hound, this breed of domestic dog is famous for its massive size. This breed holds the record for the world’s tallest dog at 44 inches and was originally bred to hunt wild boar and deer in Germany.

Fila Brasileiro: The Fila Brasileiro (also known as the Brazilian Mastiff) is a large dog developed in Brazil. It has great tracking abilities but is an aggressive and impetuous dog. Owing to its size, temperament and potential for aggression, the Brazilian Mastiff has been banned in many countries.

Akita Inu...A large spitz breed of dog that originated from mountainous regions of Japan, it is known for its two breed types: the Akita Inu (Japanese Akita) and the Akita (American Akita). A strong, independent and dominant breed, they are affectionate with family members but are aloof and sometimes aggressive with strangers due to their territorial attitude.

Boxer: Though not typically aggressive by nature, they are listed in our 25 most dangerous dogs breed list due to 48 negative incidents involving the breed from 1982 to 2012. Originally from Germany, where they can grow from 50 to 70 lbs, their bright, playful and energetic personalities are countered by their ‘headstrong’ temperament.

Wolf Hybrid: As the name implies, the Wolf Hybrid (also known as the Wolf dog) is a cross breed between a dog and a wolf (typically a grey wolf). Consequently, Wolf-dog hybrids are a mixture of genetic traits resulting in less predictable behavior patterns compared to either the wolf or dog.

Chow Chow: Though they seem to be distant and independent, this breed of dogs requires staunch attention from their owners if they do not want them to grow aggressive and ill-tempered. Originally from China, the 50 to 70 lbs. Chow Chow can also be referred as Songshi Quan or "puffy-lion dog." This dog has discernment skills against strangers and can be fiercely protective of their owners. Considered high-risks dogs, they may require insurance due to 238 fatalities attributed to this breed from 1979 to 1998. Though they can be housed in apartments, they need daily physical activities and exercises so as not to become dangerous.

Doberman Pinschers: Famed for their alertness, loyalty and intelligence, this breed of dogs is considered to be the best guard dog--they only attack if they are provoked or sense that their family and their property is in danger. A breed of domestic dog that originated from Germany in 1890, developed by Karl Friedrich Louis Doberman (hence the name), they can weigh as much as 65 to 90 lbs. They exhibit aggressive behavior directed to strangers and other dogs, though owner-directed aggression is low.

Huskies: Used to pull sleds in the northern regions and differentiated for their fast pulling style, they were also utilized for racing and adventure trekking. However, they can be dangerous to smaller animals due to their strong predator instinct and are known for being destructive if they are bored.

Alaskan Malamutes: A breed of dog related to the Siberian Husky, this breed requires daily exercises to be happy, else they will become bored, disobedient and destructive. This large breed of domestic dog can grow from 70 to 100 lbs. and are perfect companion for pursuits like carting, mushings, bikejoring, and skijoring. Since they are known for their strong independence, they can be difficult to train, cope poorly with smaller animals, and are unreliable as watchdogs.

Rottweiler: Rottweilers are a powerful breed with well-developed genetic herding and guarding instincts. As with any breed, potentially dangerous behavior in Rottweilers usually results from irresponsible ownership, abuse, neglect, or lack of socialization and training. Nevertheless, the Rottweiler’s strength is something that should not be overlooked.

German Shepherd: A breed of dogs that originated from Germany, the German Shepherd can weigh as much as 70 to 100 lbs. Known for being intelligent, confident, alert, vigilant, and fearless; the police use them for their K-9 units. However, caution must be exercised with Shepherds as they can become overprotective of their family and territory, and if not socialized correctly; they can attack strangers.

Pitbull: The term "pit bull" encompasses certain breeds of dog from the American Pit Bull Terrier, the Staffordshire bull terrier, the American Staffordshire terrier, and the American Bulldog. Originally bred for baiting bulls and bears, the majority of their breeds were also used for dog fighting in numerous parts of the world and is considered the most dangerous dog in America.

Caucasian Ovcharka: The Caucasian Ovcharka (also known as the Caucasian Shepherd) was bred to protect livestock. The typical Caucasian Ovcharka is assertive, strong-willed and courageous. However, unless properly socialized and trained, the Caucasian Shepherd may exhibit ferocious and unmanageable tendencies since it does not accept people it does not know and has a powerful urge to defend.