Several years ago, I found myself in possession of an abandoned baby deer mouse. She was too little to survive on her own, so when it was clear that no mousey help for her was coming, I took her in as a pet.

Like all mice, she grew up quickly. Being a mouse means everything wants to eat you, so you grow up and have lots of babies as quickly as possible in the hopes of leaving some offspring before you are chomped.

It also means not investing much in any one baby, since you have lots. This may be how Garlic Jack ended up alone and crying in my apartment in the first place: if her mother didn’t have the energy to care for her, she would not have hesitated to abandon her. Stressed-out mouse mothers often will even eat their babies, taking that energy back for a less stressful, more promising time.

Mice are extremely social animals, not unlike humans, and do no better than we would in solitary confinement. So when Garlic Jack was big enough to hold her own, I got her some domestic mouse friends, “feeders” from the local pet store.

From the first it was obvious who was the product of stringent natural selection and who had been bred to be snake food. They lumbered; she zoomed.

Domestic mice are bigger than she is, with proportionally smaller heads, ears, and eyes. Where she is built to survive famine and hear and see predators, they are built to thrive under human care. Since most humans breeding mice intend them as food for other animals, domestic mice have not lost their ancestral ability to produce lots of babies very fast, but they have lost some of their predator-detection abilities (detecting the snake does not help your survival chances when you are locked in its cage), and they have acquired a tolerance for human handling.

You cannot handle Garlic Jack. You cannot catch her: even gravity seems to lose its grip on her occasionally.

Strangely, even in human care—which the domestic mice are adapted to, and she is not—she has proved hardier than they. Over three years she’s outlived several waves of domestic friends; none of them have come close to matching her longevity. This is probably because domestic mice are inbred, and so suffer from accumulations of recessive mutations that make them less hardy even under the best conditions.

At three years old she is perhaps less shiny than in her youth, but she is still a creature of piercing alertness and pure quicksilver energy. She refuses to run in the wheel properly: instead, she runs until she gets up momentum, then clings while the wheel whirls her ’round and ’round. I don’t know what natural experience this could possibly evoke, but she seems to love it.

Despite their genetic differences, she and the domestic mice get along well.