Rat lovers are used to being misunderstood.
"When my husband told his ex that we got rats, she said, 'On purpose?'" says Tami Kaplan of Waltham, Mass., proud owner of three of the maligned rodents.
Look past your preconceptions and you might fall in love, like Robin Rushlau of Dresden, Maine, foster and adoption co-ordinator with Mainely Rat Rescue.
"I had friends who had rats — I wouldn't even look at them. I thought they were the creepiest pets ever," she says.
But her daughter convinced her to care for one while the owners were on vacation. He was far from the perfect specimen — obese, lice-ridden and the exact colour of a wild rat — but, Rushlau says, "I couldn't believe how wonderful he was. At the end of the two weeks I wouldn't let him go back."
In contrast to their icky reputation, rats are playful and affectionate, their owners say. They're also a lot smarter than you might realize.
Erin Stromberg is a keeper at Think Tank, an exhibit at the National Zoo that highlights animal cognition. Alongside our brainy relatives the orangutans, Think Tank houses three brown rats.
Stromberg suggests that the conventional dislike for rats is due partly to their intelligence. They're a challenge to control because they're flexible and adaptable enough to learn to avoid new dangers and exploit new food sources, and, she says, "Flexibility is one of the key components of how we define thinking."
Stromberg also points to some recent science that demonstrates rats' capacity for empathy: "When given the choice, rats chose to free other caged animals rather than take a food reward."
The result is a pet that, as Rushlau describes it, is much like a small dog, but less time-consuming to care for. And compared to other rodents, Kaplan observes, rats are tidier than guinea pigs and less likely to bite than a hamster.
Rats love human companionship because they are social animals — in the wild they live in large colonies. That means they also need the company of their own kind, so you should keep at least two. A multi-level cage will allow them to climb, and takes up less floor space.
A rat's other basic needs are fairly simple. Mainely Rats recommends feeding them a good-quality, lab-rat diet, and some fresh fruits and vegetables. Since they are rodents, their teeth grow continually, so you need to supply safe items for them to chew on.
If you're interested in a rat as a pet, try looking for a rescue group. Rushlau's Mainely Rat rescue, for example, has rats in foster homes throughout New England, New Jersey and New York, and last year adopted out about 700 animals.
Rats often end up with rescue groups because pet stores are careless about determining their sex and keeping the sexes separate. Pet-store buyers may end up with a pregnant female, or find out the hard way that their pair of rats isn't the same sex after all.
Be sure that if your rat needs medical care, you take it to a vet with rodent experience. Be aware that rats are susceptible to tumours and serious respiratory problems, Kaplan says. If your rat is sniffly, don't assume it's just a cold. And feel the animal frequently for any lumps.
The other downside is that rats don't live long — only two to three years.
"You get very attached to them, and it's hard to have pets that don't live that long," says Kaplan.
On the other hand, Ruslau observes, this sad fact can be an advantage if you're a parent whose child wants a pet; you won't be left caring for it for years after they go away to college. However, you may find yourself with a rat obsession of your own: When they adopt out rats to families with kids, she says, "It happens so many times that the parents fall in love."