A family who recently moved to Calgary from Vancouver unknowingly broke the law.

They brought their pet rat with them without realizing the rodents are illegal in Alberta.

"They thought if it's illegal to have in Alberta they should turn it in. And so they turned it in to us and it's a very domesticated pet rat," says Bill Bruce from Animal and Bylaw Services.

Matilda now sits on a desk locked in a sturdy cage at Animal Services.

She is awaiting her deportation to Vancouver where she will be handed over to a rat rescue society.

"We would normally euthanize a rat but, in this case, because it was a family pet and domesticated we had the ability to transport it – at no cost to the taxpayer – it was the humane choice," says Bruce.

A volunteer will drive Matilda to Vancouver and cover all the expenses. The pet rat will then be quarantined for 10 days before a new home is found for her.

In the meantime, the vet that is taking care of Matilda says she's been a good office mate. "They are very social and because they are so smart you can do little fun tricks with them, you can have more of a relationship with them," says Marta Alguacil, a veterinarian with Animal Servcies.

Alberta is the only province in Canada that bans rats as pets.

The fine for owning one can be as high as $5,000 dollars.