Ever heard of the Paisley Terrier, or St John's Water Dog?

Most animals become extinct for environmental reasons. Sadly dogs seem to disappear for other reasons, particularly if they don't fit with the function or fashion of the day.

Some are interbred or die due to genetic disorders or predators, but when a breed is gone, it's truly gone.

Here's a look back at the breeds, from ancient to modern eras, that tragically did not stand the test of time.

1. Hare Indian Dog

Also known as "Trap Line Dogs," this Canadian breed died out in the 19th century. Often compared to a coyote due to its agility and knack for hunting, the numbers of the dog eventually fell as aboriginal hunting methods became less popular.

2. St. John's Water Dog

St John's Water Dogas are the little known ancestor of modern retrievers, including the Golden Retriever and Labrador Retrievers.

Due to severe restrictions and taxes placed on dog ownership in New Foundland in the 19th century, the breed swiftly declined. The last pair existed in the 1980s, but were both males, therefore ending the breed.

3. Braque du Puy

This breed of French hunting dog is thought to have garnered its name from two brothers who bore the last name "Dupuy" or "Du Puy".

The breed was not as popular as other French Braques and became extinct in the 1970s due to excessive cross-breeding.

4. Cordoba Fighting Dog

The Cordoba was a crossbreed of several dogs - the Bull Terrier, English Mastiff, Boxer, and Bulldog.

Famed for its willingness to fight to the death, the breed died out in the mid-20th century.

5. Russian Tracker

Also known as the Russian Retriever, this huge dog measured about 30 inches at the shoulder could weigh up to 100 pounds.

The breed disappeared in the 1800s, though the exact cause of extinction is not known.

6. Argentine Polar Dog

These large dogs aided Argentine armies by protecting their Antarctica bases.

The canines had thick fur and sharp fangs but died out when they were moved from Antarctica in 1994.

7. Moscow Water Dog

This breed was last seen sometime during the 1980s.

Though it was developed by the Russian Government and Navy in the hopes of creating an optimum rescue dog, it failed to survive in the long term.

8. Talbot

The ancestor of the favoured beagle and bloodhound breeds, this British hunting dog was popular in the Middle Ages.

It was small to medium-sized and white colored, but needed constant care and lacked purpose, which led to its downfall.

9. English Water Spaniel

With a lean and long-legged body, the English Water Spaniel was widely used for hunting duck and waterfowl.

Referred to in two of the works of William Shakespeare, their prominence did not last long. The breed went extinct in the early 20th century due to the preference of importing St John's Water Dogs from Newfoundland as hunting companions.

10. Coton de Reunions

A bichon-type of dog, originating from the small African island of Reunion, it is believed these dogs were brought to the island from France or the Canary Islands.

Reunion lost much of its commercial standing when the Suez Canal opened in 1869, causing the breed to fade away.

11. Cumberland Sheepdog

Remarkably similar in appearance to the Border Collie, this breed of dog hails from northern England.

Once a popular shepherd dog, there is no record of the Cumberland Sheepdog after the beginning of the 19th century. Instead, the breed morphed into the Border Collie.

12. Paisley Terrier

With a long, silky coat, the Paisley Terrier was bred to be a companion and show dog.

The popularity of the breed fell drastically towards the end of the 19th Century, as dog show judges favoured the Yorkshire Terrier and the Skye Terrier.

13. Toy Bulldog

A breed that existed in England in the 18th and early 19th centuries, attempts to develop this dog after proved fruitless. Though bulldogs sometimes produce dwarf-sized offspring, they tend to suffer from health and fertility problems.

14. Molossus

One of the oldest breeds on this list, the Molossus are thought to have existed in ancient Greek times. With little information surviving, it's hard to determine the appearance and function of the dogs.

The breed was instrumental, however, in the development of the Pitbull, Rottweiler, and Great Dane, to name a few.

15. Kurī

These dogs have a rich history, as they were brought to New Zealand on canoes by Polynesians in the 13th century.

The small, long-haired dogs are believed to have died out due to cross-breeding with dogs brought by Europeans in the early 1800s.

16. Techichi

Similar looking to the Chihuahua, these small, mute dogs were native to Mexico in the ninth century AD. Their breeders, the Toltec people, believed the dogs possessed supernatural powers, and often sacrificed them so they could lead their deceased owner in the underworld.

17. Hawaiian Poi Dog

Relied upon by Native Hawaiians as a spiritual protector of children and a source of food, these useful dogs died out in the early 20th century.

European settlers brought over feral dogs, which sadly interbred with the poi dogs.

18. Bullenbeisser

Native to Germany and its neighbouring countries, the Bullenbeisser specialized in Bull-baiting and boar hunting.

Crossbreeding caused the breed to die out, though its legacy remained in the Boxer, one of the most popular dog breeds in the world.

19. Salish Wool Dog

Prized for their white, long-haired coats, these dogs were kept by the Salish peoples, of the now Washington state and British Columbia.

Kept in packs of about 12 to 20 animals on islands and in gated caves, these dogs were sheered like sheep.

20. Alpine Mastiff

Believed to be the largest dog breed in England in the early 19th century, these dogs derived from the Molosser dog breed.

Thought to have gone extinct in 1815 due to crossbreeding with other large European mountain dogs, the breed formed the basis of St. Bernards and Mastiffs.