Grace, Jennifer’s and my Chinese dwarf hamster, died this morning of cancer. She went abruptly: we first noticed a few days ago that she was puffing up, and just this morning I saw her moving around her cage, in my peripheral vision, when we sat zazen in the living room at 7:30. I went to work and Jennifer texted me at 10:30 that Grace was dead.

Grace is survived by her sister Ada. They were named after computing pioneers Grace Hopper and Ada Lovelace, but they did not take after those rational women. The sisters had a tumultuous relationship ever since we brought them home from the Union Square pet store. Mornings and evenings we heard them squeaking reprimands at each other and slamming the furniture in their cage. After one of these tempests, Grace would run off steam on the wheel while Ada swooned on the bedding in the corner. An hour later, they were curled up together asleep. Still, their conflict only worsened with time. This summer we had to bring Ada to the vet for an eye injury, and there was no denying that Grace needed her own apartment. We set her up in a 10-gallon aquarium around the corner from Ada, and from then until Grace’s death, she saw her sister only during supervised visits.

Although she did not have Grace Hopper’s temperament, Grace the hamster did share her forebear’s passion for engineering. She dug tunnels and built earthworks in her cage each night. Her designs were particularly concerned with ergonomics. Each time we smoothed out the fluff in her cage, Grace rebuilt the mound leading up to her water bottle so she could sip from it in comfort.

Grace was a disciplined athlete, running several marathons per night on her wheel, and a doughty explorer who steered her hamster ball to the farthest reaches of the apartment. But above all she was a good friend who never bit us and sat companionably in our hands whenever she came out to visit. We hope Ada sees, in the sharper focus that distinguishes a life in retrospect, the affection her sister bore her despite their differences. Perhaps that understanding will bring her some comfort until their ultimate reconciliation.