The baseline footprint for a running, climbing animal
Degus are daytime athletes. A bonded pair will spend their waking hours running a wheel, climbing every level, excavating the substrate and re-arranging the cage, and the enclosure has to absorb all of that without becoming contested ground. As a working baseline, plan on roughly a metre of width, half a metre of depth and a metre of height for a pair, and step up a size for a trio or a group of four, where the extra floor and one extra level noticeably reduce the squabbling over prime spots. Height earns its place in a degu cage, but ground floor still matters most, because digging, dust-free foraging and the wheel all happen at base level.
Commercial rat and ferret cages are the usual starting point, since degus share their size and climbing style — but every candidate cage still has to pass the three degu-specific checks below before the tape measure is even relevant.
Solid levels, because degu feet are not built for wire
Degus standing and running on bare wire mesh develop sore, damaged feet — bumblefoot is the condition keepers fear — so any cage with grid floors or grid shelves needs those surfaces covered or replaced before the degus move in. Solid metal or kiln-dried pine shelves are the fix, and wooden ones come with a bonus: degus are allowed, expected, to chew them slowly away, which wears teeth while it furnishes the cage. Plan shelving so the cage reads as a route — levels overlapping at staggered heights, ramps or branches between them — because degus commute up and down constantly and a tall cage with one ladder is a tower with a bottleneck.
The base tray deserves the same scrutiny as the shelves. Plastic trays are chewed open by degus with time and motivation, so choose a deep metal tray, or a cage design whose base is glass or metal. Depth matters as well as material: a tray that holds a genuinely deep layer of substrate, or room inside the footprint for a separate digging box, answers the degu's other great drive, which is to excavate.
Bar spacing and door security for a small escape artist
Adult degus look chunky; young degus are not, and spacing that safely holds an adult can pass a juvenile like a turnstile. Keep bar spacing around a centimetre and a half or less, and check the corners and door surrounds where spacing often widens in cheaper cages. Doors should latch firmly — degus watch hands, learn catches, and test them afterwards. If the cage has a large front door for access, a secondary clip is cheap insurance against the day a catch is left half home.
Wheels complete the internal audit: solid-surfaced, and big enough that a running degu's back stays straight rather than arched — around thirty centimetres across is the size keepers settle on — mounted clear of shelves so the climbing route does not cross it.
Numbers in hand before you order
Degus are almost always kept in pairs or groups, so size for the group you will actually have, including the fact that today's pair may become a trio when a rescue joins. Measure the space at home first, allowing a metre of width plus extra clearance to open doors and pull trays out, and remember the cage stands somewhere cool and out of direct sun, since degus overheat in a sunlit corner however generous the floor plan.
If two cages both pass every check and the choice still will not resolve, bring the measurements together in one place before ordering either. For anything that remains unclear, put a follow-up question to KinsLe's Kinny; he answers using the KinsLe Answers library.