Lawyers and Legal Issues: Dog Owners’ Guide

List of American lawyers for pet-related issues
American Dog laws
Dog Bite Law
(American site)
Links for Dog Owners and Owners of Injured Animals

What Treatment Do I Get if I Might Have Rabies
Legal Dictionary
Ministry of the Attorney General

Going to court, getting a lawyer, etc.
Ontario Statutes and Regulations
Help for you prepare to make a claim in Small Claims Court
if you don’t have a lawyer

Animal Laws and Cruelty Prevention 
(US) Animal Law Review - journal
Ontario, Canada:
In Ontario, the Ontario Society for the Prevention of Cruelty to Animals (OSPCA) and the local police are the best place to start if you suspect animal cruelty.
Ontario Laws About Animals include: Animals for Research, Animal Health ActDog Owners Liability Act and Pit Bull Controls, Pounds Act.  There are also federal laws (below) and municipal (town, city and township) laws in about 600 municipalities (check out this page for examples including Toronto and Guelph).  Municipalities also tend to have regulations about  cleaning up dog waste (sample Stoop-and-Scoop By-law), keeping private properties clear of animal waste (sample Property Standards By-law), and leash laws (sample leash free parks and leash laws description from Guelph).
What Happens If I See A Dog Trapped in a Hot Car, Or Starving
Under the federal Criminal Code and other laws, you have no specific authority to enter into a vehicle to assist a dog.  What if you decide to break the window and gain entry anyways? Section 430 (1) of the Criminal Code states that “Every one commits mischief who willfully (a) destroys or damages property”. So while you may consider your reason for breaking the window a good one, you may potentially be investigated and arrested for mischief and have to explain your actions in court.  Saying you broke a window because a dog was panting may not likely be sufficient.  If you are found guilty and convicted of mischief, you will have a criminal record which may affect your career, travel and life.
Let’s look at impulsive “smash the window” action a bit further. Have you ever tried to break a car window? It is more difficult than you think. What are the risks? You could seriously hurt yourself. You could also shatter glass all over the dog and injure it further. The dog may react defensively and bite you as you attempt to get a hold of it. Or the dog may jump from the car and get hit by a car in its attempt to escape. Or the dog may be successful in its escape and continue to run away, therefore defeating the purpose of you trying to help it.  What is your plan after you’ve got the dog? Are you going to transport the dog to a veterinary clinic? Who will pay the bills? Since you have not acted under any authority, there is no requirement for the owner to reimburse anyone for the costs of treatment.  Also, a veterinary clinic may or may not perform veterinary care at no cost, especially if the care is not deemed emergency.  
We're not saying “take no action.” Dogs die every year in hot cars or are victims of cruelty and minutes can make a difference. Rather, make an informed decision with a priority of helping the dog and considering the risks of your actions.  IF AT ALL POSSIBLE – contact the person who has authority to resolve the situation and have them lead the response.    
For emergencies in Ontario:
Investigations -1-888-668-7722 (for emergencies during weekends or evenings dial ext. 1)
Animal welfare concerns go to your closest Ontario SPCA Community. See the directory for contact information.
More legislation:
Animals for Research Act
This Act providing a focus for humane care and use of all animals in research through establishing minimum standards. The purpose of the Act is threefold: to maintain a minimum standard of care and well-being for all animals used in research; to protect research animals from unnecessary pain; and to assure that dogs used in research are obtained legally and are not wanted as pets. The Act requires all researchers to be accountable to animal care committees for their use of animals; protects all vertebrates; prescribes minimum standards and requirements; provides minimum redemption times for animals impounded; and provides minimum standards for municipal pounds. The Animals for Research Act is enforced by inspectors who are appointed by the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).

Dog Owner's Liability Act
An Act designating dog owners (or the parents/guardians of owners who are minors) responsibility for bites or attacks by their dog on a person or other domestic animal. An exclusion may be made if the bite or attack occurred on a person in the process of committing a criminal act or in the destruction of the owner's property. The Act covers all breeds of dogs but has specific regulations for pit bull owners including a mandatory requirement for all dogs to be muzzled and leashed off the owner's property. In case of a dog bite or attack, the Ontario Court of Justice may order one of the following: destruction of the dog; measures for more effective control; confinement; leash; muzzle and prohibition of the individual from dog ownership for a specified period of time. The Dog Owner's Liability Act is enforced by local municipalities and police forces.
Federal Laws include:

Criminal Code of Canada - Cruelty to Animals
In Part XI of the Criminal Code, Wilful and Forbidden Acts in Respect of Certain Property, Section 446-1 states that it is a federal offence to "wilfully cause or permit to be caused, being the owner, unnecessary pain, suffering or injury to an animal or by wilful neglect, cause damage or injury to animals while they are being driven or conveyed." In Ontario, Inspectors and Agents of the Ontario SPCA can and do lay charges under the Criminal Code in cases of severe cruelty or neglect.

Health of Animals Act
Governs the control or elimination of diseases and toxic substances, including regulations for the humane treatment of animals and generally governing the care, handling and disposition of animals, the manner in which animals are transported within, into or out of Canada, and providing for the treatment or disposal of animals that are not cared for, handled or transported in a humane manner.

Veterinarians Act
It is mandatory for veterinarians in who have reasonable grounds to suspect abuse or neglect of an animal to report that suspicion to an appropriate branch of the OSPCA.  Section 17.(1)6.iv of Ontario Regulation 1093 under the Veterinarians Act contains an exception to the duty of confidentiality that veterinarians owe their clients.  In Ontario, Canada vets are also required by law to report all bites to the government who assesses the risk to human health and the government may take action as below.

Landlord Tenant Act (coming soon)

Condominium Act
Condos and coops in Canada are allowed to set their own rules according to a provincial (our equivalent of state) law.  Under this law, which gives condo boards the ability to set most rules for how people use the common areas, most condos and some in my area have a "no dog over 25 lbs. rule" and "one dog per unit rule" or some restriction on dog size and quantity. Condos here also regularly ban dogs from elevators and require owners to carry their dogs down the stairs (which they use as a polite way of limiting the size of dogs and there are few willing to carry dogs like Great Danes.) They can also restrict where - if at all - dogs are allowed to pee in common grassy areas (like near the front door.)  In fact, as an Ontario Superior Court decision (6726) in 2001 showed, a condo board is within their rights to require the removal of a dog for peeing on balcony.  Condo boards must act reasonably in enforcing condo rules, but the courts will not substitute their own opinion for the board and generally the condo board is allowed a pretty broad discretion.