Roof Rat Laws › United States › Maryland
Summary. In Maryland, keeping, breeding, and selling a domesticated roof rat is very likely fine, but it rests on an undefined term rather than a clear yes. Maryland’s ‘dangerous animal’ ban (Md. Criminal Law §10-621) lists big cats, bears, primates, and the like, no rodents, and the wildlife regulation (COMAR 08.03.09.03) says it does not prohibit possession of ‘domesticated rats and mice.’ The catch is that ‘domesticated rats’ is not taxonomically defined, so whether a captive-bred R. rattus qualifies (rather than only the fancy rat, R. norvegicus) is open to interpretation. That is why we code keeping, breeding, and selling as unregulated / unclear rather than a definite legal. No rodent-specific import certificate is mandated (Maryland’s CVI/rabies rules cover only livestock, poultry, and dogs/cats/ferrets), though a general interstate CVI is customary and worth confirming with the State Veterinarian before importing.
legal note
This is a research aid, not legal advice; rules change and are interpreted by local officials. Verify with the official source before acting.Status by activity
Keeping / owning Unregulated / unclear
Confidence: High · Last verified 2026-06-07
Md. Criminal Law §10-621(b)(1) lists the live animals a person may not possess, and no rodent appears on it. DNR’s possession regulation COMAR 08.03.09.03(C) affirmatively states it does not prohibit possession of ‘domesticated rats and mice,’ which covers a captive-bred domesticated roof rat. No DNR captive-wildlife permit applies to domesticated rodents. Gemini DR-verified: rodents aren’t in MD’s dangerous-exotic ban (Crim. Law sec.10-621), but COMAR 08.03.09 requires a permit for ‘live wildlife’ with an exemption for ‘domestic rats’ that ISN’T taxonomically defined — so whether captive-bred R. rattus qualifies (vs only R. norvegicus) is genuinely ambiguous and open to DNR officer interpretation.
Sources: Md. Code (via MSU Animal Legal & Historical Center), Maryland DNR (Division of State Documents)
Breeding Unregulated / unclear
Confidence: High · Last verified 2026-06-07
§10-621 prohibits ‘breed’ only for the enumerated dangerous species; rodents are not enumerated. COMAR 08.03.09.03(C) exempts domesticated rats and mice from import/possession restrictions, and no DNR breeder license reaches domesticated rodents. (Federal USDA/AWA dealer licensing is a separate matter triggered only by commercial wholesale/sight-unseen thresholds, see United States.) Gemini DR-verified: private hobby breeding isn’t state-regulated (game husbandry licenses cover game birds/mammals, not non-game rodents); county zoning/kennel/pet-shop rules are the layer.
Sources: Md. Code (via MSU Animal Legal & Historical Center), Maryland DNR (Division of State Documents)
Selling or giving away Unregulated / unclear
Confidence: High · Last verified 2026-06-07
§10-621 bars offering for sale/trade/barter/exchange only for the listed dangerous animals; rodents are not listed. DNR’s sale/transfer rules apply to permit-acquired and native/regulated wildlife, not to captive-bred domesticated rodents exempted by COMAR 08.03.09.03(C). No Maryland state pet-dealer license is required for private rodent transfers. Gemini DR-verified: the state doesn’t regulate rodent sales (the retail-sale ban targets dogs/cats); a LOCAL ‘Commercial Animal Establishment’ license is required and varies by county.
Sources: Md. Code (via MSU Animal Legal & Historical Center), Maryland DNR (Division of State Documents)
Transport & import Legal with a permit
Confidence: Medium · Last verified 2026-06-07
In-state transport of a domesticated rat is unregulated. For IMPORT, Maryland’s rabies-import rule (COMAR 10.06.02.11) applies to dogs/cats/ferrets only, and MDA’s admission rules require a CVI for livestock/poultry/dogs/cats/ferrets, there is no pet-rodent category. So no rodent-specific CVI is mandated, but a general interstate CVI is the customary document for any animal crossing state lines (note: since 2019 Maryland no longer accepts the federal APHIS 7001 ‘small animal’ form), so confirm with MDA Animal Health before importing. Gemini DR-verified: importing any companion rodent needs an Interstate CVI issued within 30 days before entry (COMAR 15.14.05.01); private-traveler enforcement is historically lax but the ICVI is mandated.
Sources: Maryland Dept of Health (Division of State Documents), Maryland Dept of Agriculture, Animal Health Program, Maryland DNR (Division of State Documents)
Restrictions & responsibilities
- Confirm CVI expectations with MDA Animal Health before interstate movement
Where: Maryland Dept of Agriculture, Animal Health Program
Official sources
- Md. Code, Criminal Law §10-621, Dangerous-animal import/possession ban (no rodents listed), Md. Code (via MSU Animal Legal & Historical Center)
- COMAR 08.03.09.03, exempts ‘domesticated rats and mice’ from import/possession prohibition, Maryland DNR (Division of State Documents)
- COMAR 10.06.02.11, Importation of Animals (rabies import certificate; dogs/cats/ferrets), Maryland Dept of Health (Division of State Documents)
- MDA Health Requirements Governing the Admission of Animals (CVI scope by species), Maryland Dept of Agriculture, Animal Health Program
Search terms: Rattus rattus, roof rat, black rat, ship rat.
Last reviewed 2026-06-07, which is when a person last read this page against its sources. Spotted an error, or know the law has changed? Email blonderoofrat@gmail.com. And if you write to the agency yourself and get an answer in writing, please forward it. Written agency replies are how 31 of these pages stopped being research and became confirmed.