It's not a kitten, a squirrel, an over-sized rat, a mini-kangaroo or even a guinea pig.
It's Charlie the chinchilla, the furry grey rodent first introduced to Canadians on Harper's Twitter stream in January in a photo that featured the prime minister gazing down at the newest addition at 24 Sussex Drive.
Charlie was rescued by the Harpers from the Ottawa Humane Society a year ago. Laureen Harper, an avid motorcyclist and animal lover, continues to foster cats and kittens, and currently has four under her care.
They include incumbent kitties Gypsy, a tortoiseshell, and Stanley, a grey tabby who sometimes has breakfast with the prime minister.
The foster felines hang out in the third-floor "animal room" — an unfurnished space with hardwood floors at the prime minister's residence. Charlie, however, is thought to spend most of his time in a cage and out of harms' way from the cats.
Earlier this year, Laureen Harper posted a YouTube video of the rodent methodically rolling around in a plastic container filled with dust as she cooed "good boy" at him. So-called dust baths help chinchillas keep their thick coats glossy and clean.
Chinchillas, native to the Andes mountains of South America, have been harvested almost to extinction due to their velvety coats. They're crepuscular, meaning they're most active around dawn and dusk, and can be challenging pets.
Capable of jumping 1.8 metres in a single leap, they also spray urine if on the defensive. They require extensive exercise and a generous supply of chew toys in order to keep their teeth worn down, a practice that prevents them from binge-eating and becoming overgrown.
Harper has argued that politicians who love cats, as opposed to dogs, are those who want to serve rather than to be loved. He's yet to weigh in on the significance of politicians who love chinchillas.