I have 30 rats as pets and only feed mice to my Ball Pythons. Pet rats are Rattus norvegicus, or Norway rats. Rattus rattus are roof rats or Black rats(tiny little things).

Everyone knows the pros of having rats as pets, but there are a few cons that aren't mentioned.

Rats get cancer.. They get cancer very easily, be it malignant or benign. They mostly get mammary tumors, which are easily removed by a qualified veterinarian. If the rat is female and is spayed early in life(4mos), then chance of them having mammary growths are greatly reduced.

I've also had rats get malignant cancer, such as squamous cell carcinoma. Tried chemotherapy drugs on them, but both rats didn't respond to treatment and had to be humanely euthanized. Any future owner needs to be prepared for this. It's not a matter of if, but when.

They can also get abscesses, which are easily treated by just flushing with chlorhexidine gluconate a few times a day. Antibiotics are generally not required unless the abscess is in a dangerous area.

They can get lint(IE carefresh bedding which is JUNK, do not use) stuck in the corners of their eyes, but hairless rats are more prone to this. If the material remains in the eye, it can cause ulcers, which can render the eye useless and it will need to be surgically removed. Ulcers are extremely painful, so if you see one of your rats squinting, some porphyrin around that eye, try flushing the eye with some lukewarm saline solution.

The rats need to be in a well-ventilated, but not drafty area. Under 75 degrees is preferable as they don't cool themselves easily. Using a good bedding such as Yesterday's News or aspen will ensure the rats don't come into contact with anything harmful. Do not use pine or cedar, it will cause respiratory distress and will eventually cause liver/kidney failure.

I always recommend either a trio of girls or a trio of boys. Trios work well because if one rat happens to pass away, the other two still have each other.

Spaying and neutering is very important(people often forget this with their dogs and cats, so why would they remember a little rat). Neutering males at a young age will greatly reduce scent marking, and the males will have soft fur from lack of buck grease production. Males can also get mammary tumors, so neutering will reduce that as well. Contrary to popular belief, neutered male rats(and other males of the dog and cat species) still get very large sized. Neutering early will also greatly reduce aggression tendencies, such as those brought on by puberty(can be violent).

Spaying females early can prevent alot of problems such as mammary tumors, uterine infections, ovarian cysts/cancer, and unwanted pregnancies. I have a dwarf female rat who is spayed and even at 2 years old, she still hand wrestles, runs all over the couch, and is a general pain in the rear, haha. She hasn't had any of the health problems normally associated with aging.

Here's a good site that I send people to if that have questions:
www.ratguide.com