What Is It?
BSL is a law that prohibits certain breeds or type of dog. BSL can take place in cities, provinces, even entire countries. This law can prohibit one from owning/keeping, breeding, importing, selling/transfering ownership of a dog of a given breed. Some regions place only restrictions or conditions on a given breed (sterilization, muzzling in public, display warning signs at home, and more), while most regions outright ban any ownership or action involved with the breed or "type" of dog.

What Breeds Are Victims of BSL?
Akita, American Pit Bull Terrier, American Staffordshire Terrier, Argentine Dogo, Canary Dog, Cane Corso, Doberman Pinscher, Fila Brasileiro, English Bull Terrier, German Shepherd, Neapolitan Mastiff, Tosa Inu, Rottweilers, South African Boerboel, wolf hybrids, and multiple others.

Exactly Why Is This A Thing?
Breed-specific laws are based on the presumption that certain dog types are prone to injurious behavior toward humans and, put simply, that banning or restricting the entire breed or dog type entirely is the answer to preventing bites or maulings.

Does BSL Exist in Canada?
Winnipeg, MB: Any dog "having the appearance of" or having physical characteristics predominantly conforming to the standards of the CKC or UKC of the American Pit Bull Terrier (APBT), American Staffordshire Terrier, and the Staffordshire Bull Terrier, are entirely banned.
Province of Ontario: "No person shall own, breed, transfer, abandon or import a pit bull, nor allow one to stray, nor train a pit bull for fighting." Dogs born before August 29, 2005, or born in Ontario within 3 months post, had to be sterilized, muzzled, kept on leash on all public and open property.

How Can I Help?
x) Learn about it and educate others on social media, at school or work, or on your own website!
x) Be a walking billboard and support nonprofit anti-BSL organizations by buying a shirt or bumper sticker.
x) Like and share educational images from topical groups such as Justice for Bullies, Not A Bully, Stop BSL.

One or a few or several or even a hundred incidences cannot and do not speak for an entire group of millions.
Injuries or deaths due to maulings are multifactorial; breed type is not causative!

Anti-BSL Resources

Justice for Bullies
Bickell Family Foundation

Some information referenced from here.