The legal pets in Massachusetts are the species on the state’s official domestic animal exemption list under 321 CMR 9.02, which you can keep without any special permit. Common household animals — dogs, cats, domestic rabbits, hamsters, guinea pigs, gerbils, certain poultry, along with llamas, alpacas, and domestic livestock — all appear on that list.1Mass.gov. 321 CMR 9.00 Exemption List Any vertebrate that isn’t on the list is presumed wild and falls under the wildlife provisions of Chapter 131, meaning you can’t legally possess it without authorization from the state.2Cornell Law Institute. 321 CMR 9.02 – List of Domestic Animals
That “list approach” is the core of the system. If the species is on it, you’re free to own the animal like any other pet. If it isn’t, the default is no.
Getting a Permit for Animals Off the List
Wanting to keep something more unusual — a native reptile, a non-domesticated mammal, an exotic bird — puts you in permit territory. The Massachusetts Division of Fisheries and Wildlife handles those applications and evaluates them individually. The agency looks at your experience with similar animals, your housing and containment plans, and the ecological impact if the animal were to escape.
Bringing any live fish, amphibian, reptile, bird, or mammal into Massachusetts from out of state is a separate matter and has to comply with the importation regulations under 321 CMR 2.15.3Cornell Law Institute. 321 CMR 2.15 – Importation, Liberation, and Transportation of Fish, Amphibians, Reptiles, Birds, and Mammals Buying a legal animal online or from a breeder in another state doesn’t exempt you from those importation rules.
Possessing a species on the state endangered or threatened list without a permit is prohibited separately under Chapter 131A and its implementing regulations.4Cornell Law Institute. 321 CMR 10.04 – Taking and Possession of Species on State and Federal Lists
Federal Prohibitions That Apply Regardless of State Law
Even when Massachusetts hasn’t specifically banned a species, federal law may. The Lacey Act prohibits interstate transport and possession of animals classified as “injurious wildlife.” The federal list covers Burmese pythons, reticulated pythons, brown tree snakes, all mongoose species, raccoon dogs, snakehead fish, and walking catfish, among others.5eCFR. Part 16 – Injurious Wildlife Federal amphibian restrictions are especially broad, covering dozens of salamander genera to slow the spread of a fungal pathogen affecting wild salamander populations.
Lacey Act violations carry federal penalties on top of anything Massachusetts might impose. If you’re considering an exotic species, checking the federal injurious wildlife list is as important as checking the state exemption list.
Penalties for Keeping a Prohibited Animal
Penalties under state wildlife law depend on the specific provision violated and, in some cases, the animal involved. Under Chapter 131, Section 90, fines generally start at $200 and reach up to $5,000 for unlawful possession of a bear. Imprisonment runs from 90 days to one year depending on the offense.6Mass.gov. Massachusetts General Laws Chapter 131 Section 90 – Penalties A court can also order the animal confiscated, which typically means it goes to a licensed facility rather than back to the owner.
Rabies Vaccination and Licensing for the Pets You Can Keep
If your pet is a dog, cat, or ferret, state law requires rabies vaccination by a licensed veterinarian once the animal reaches six months of age. An unvaccinated animal brought into Massachusetts has to be vaccinated within 30 days of arrival or upon turning six months old, whichever comes later. Your vet issues a certificate showing the vaccine type, lot number, and expiration date. Skipping the vaccine can bring a fine of up to $100.7General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 145B – Rabies Vaccination
A local board of health can grant a rabies exemption for a defined period if a veterinarian certifies that vaccination is medically inadvisable for a specific animal.
Dogs need one more thing: a license. Every dog over six months old must be licensed in the city or town where it’s kept, and you’ll usually need to show proof of rabies vaccination when you apply.8General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 137 – Dog Licensing Fees vary by municipality and are typically higher for intact dogs than for spayed or neutered ones.
Local Rules Your City or Town Can Add
Massachusetts municipalities can pass their own animal ordinances as long as they don’t conflict with state law.9Mass.gov. Animal Laws and Regulations in Massachusetts 2025 Edition Local rules commonly cover leash requirements, the number of dogs or cats a household may keep, and waste cleanup. Fines for local ordinance violations generally run from $50 to a few hundred dollars.
What a city or town cannot do is regulate dogs by breed. State law explicitly prohibits municipal breed-specific rules, and a dog’s breed cannot by itself support a dangerous dog determination.10General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 157 – Dangerous Dogs A local ordinance targeting pit bulls, Rottweilers, or any other breed conflicts with state law.
Dog Ownership Rules Beyond Licensing
Because dogs are the most heavily regulated pet in the state, a few additional statutes shape what lawful ownership actually looks like day to day.
Outdoor Tethering
Under Chapter 140, Section 174E, you cannot tether a dog for more than five hours in any 24-hour period, and outdoor tethering between 10 p.m. and 6 a.m. is not allowed unless it lasts no more than 15 minutes with the owner present. Puppies under six months cannot be tethered outside at all.11General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 174E – Dog Tethering
Equipment matters too. Tethers have to be designed for dogs; logging chains and improvised restraints don’t count. No tether can weigh more than one-eighth of the dog’s body weight, and choke or pinch collars cannot be used for tethering. You also cannot leave a dog outside during any weather advisory, warning, or watch, or in conditions that pose a health risk given the dog’s breed, age, or physical condition.
Penalties escalate: a written warning or up to $50 for a first offense, up to $200 for a second, and up to $500 for a third, with possible impoundment at the owner’s expense or loss of ownership.
Animals in Hot or Cold Vehicles
Chapter 140, Section 174F, in effect since 2016, prohibits confining any animal in a motor vehicle when extreme heat or cold could reasonably threaten the animal’s health. Animal control officers, police, and firefighters may enter a vehicle by reasonable means to rescue the animal after making reasonable efforts to find the owner, and the responder must leave written notice identifying themselves and where the animal can be retrieved.9Mass.gov. Animal Laws and Regulations in Massachusetts 2025 Edition
The Dangerous Dog Process
Any person can file a written complaint with the local hearing authority alleging that a dog is dangerous or a nuisance. The authority investigates and holds a public hearing with sworn testimony, then either dismisses the complaint, labels the dog a nuisance, or classifies it as dangerous.10General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 157 – Dangerous Dogs
Growling, barking, or the dog’s breed cannot on their own trigger a dangerous designation. A dog that reacted proportionally to being provoked, protecting its owner, or defending itself from an intruder who entered its enclosure is not automatically dangerous. Children under seven get a rebuttable presumption they were not provoking or trespassing.
If the dog is classified as dangerous, the hearing authority can order any of the following:
- Confinement indoors or in a securely enclosed, locked pen with a roof on the owner’s property.
- Muzzling and, when off the owner’s property, restraint on a chain or tether rated for at least 300 pounds and no longer than three feet.
- Liability insurance of at least $100,000, or proof of reasonable efforts to obtain it.
- Permanent identification such as microchip data, photographs, or veterinary records.
- Spaying or neutering, unless a veterinarian certifies it is medically inadvisable.
- Euthanasia in the most serious cases.
Owners have 10 days to appeal a dangerous dog order to the district court.
Assistance Animals Are a Separate Category
If the animal is a service animal or emotional support animal rather than a pet, the analysis changes, and this matters most in housing. Under the federal Fair Housing Act, landlords must grant reasonable accommodations for assistance animals even in no-pet housing, and they cannot charge pet deposits or pet rent for one. Trained service animals and emotional support animals both qualify.12HUD.gov. Assistance Animals
If your disability and need for the animal aren’t obvious, the landlord may request documentation from a healthcare professional confirming a disability-related need. They cannot demand a specific form, ask about your diagnosis, and can only deny the accommodation if it would create an undue financial burden, fundamentally change operations, or the specific animal poses a direct safety threat no other accommodation can address.
In stores, restaurants, and other public spaces, the Americans with Disabilities Act applies but is narrower. Only dogs individually trained to perform a specific task qualify as service animals under the ADA; emotional support animals do not. Staff may ask only two things: whether the dog is a service animal required because of a disability, and what task it has been trained to perform. They cannot ask about the disability or require documentation.13ADA.gov. ADA Requirements: Service Animals
Assistance-animal status does not exempt a dog from the state’s rabies vaccination or municipal licensing requirements. The federal rules govern access and housing; state ownership rules still apply to the animal itself.