Rat8 Hub — Fancy pet rat keeping — cage floor space and | rat8hub.com
The four measurements that decide whether a cage is safe: floor space per rat, total floor for the group, bar spacing and wheel diameter.
Start with the only unit that matters: floor space per rat. The minimum is 0.19 m² (2 sq ft) per rat for a pair, and 0.28 m² (3 sq ft) per rat is the comfortable figure. Everything else on this page is a consequence of those two numbers.
Worked examples. A pair needs 0.38 m² (about 4 sq ft) at minimum and 0.56 m² (about 6 sq ft) in comfort. A trio needs 0.57 m² minimum and 0.84 m² (about 9 sq ft) comfortable. Judge the numbers against the animal: an adult buck weighs 300-500 g, a doe 250-350 g, and either stretches 35-45 cm from nose to tail.
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Bar spacing: 13 mm (1/2 in) is the maximum gap for adults, measured at the widest point of the opening. The reasoning is mechanical — a wider gap lets a rat work its head and shoulders through, and a leg pushed into a wide gap at the wrong angle does not come back cleanly. The 13 mm figure is set for adults; younger, smaller rats need tighter spacing still.
Wheel diameter: 28 cm (11-12 in) is the floor for an adult, and the running surface must be solid. The reasoning is the spine: on a smaller wheel the rat cannot straighten its back at stride, so every step is taken bent. Wire and barred wheels fail a different test — feet and toes drop through the gaps at speed.
Once the shell passes these four checks, the furnishing order and the cleaning clock take over — see How to Set Up a Rat Cage, Step by Step — and the daily ration in grams is on the Rat Diet and Daily Feeding Chart.
Further reading