So, how did a wallaby — smaller cousin to the kangaroo and native to Australia — come to be caged and living in a garage in East Rockaway?

That’s just what the Nassau County SPCA was looking to determine, after removing the creature Tuesday afternoon from a dog-run type enclosure covered with sheets that was inside a garage at a Seawane Road residence, said Gary Rogers, SPCA spokesman.

Described as young and male by the veterinarian on the scene, the animal was “severely underweight” and suffering from muscle atrophy, Rogers said.

The creature, which SPCA staff had been feeding lettuce, has been taken to Mineola Animal Hospital, where veterinarian Dr. David Kolins said he was emaciated, probably half the appropriate body size and was “ravenous, ravenous, ravenous.”

Kolins was just about to look into ordering special wallaby food for overnight delivery.

X-rays indicated no evidence of arthritis, meaning muscle loss would not be related to that condition, he said. Blood work was expected back on Wednesday.

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It was unknown how long the wallaby had been kept in the garage, or the animal’s origins. It’s an open investigation, and the SPCA is looking into bringing charges against the person responsible for its presence, Rogers said.

It’s illegal to keep such wild creatures in Nassau County, and any penalty would be determined by the Town of Hempstead, he said. The SPCA is looking at the wallaby’s eventual placement in an animal sanctuary, he added.

As cute as a wallaby can be, Rogers said, the animal can be dangerous, and with “very strong legs, they can defend themselves,” especially if they feel cornered.

On Tuesday, Kolins was able to enter the enclosure and “scoop him up in his arms,” Rogers said, as the wallaby was low on strength and focused on munching on the lettuce.

According to NationalGeographic.com, wallabies are herbivores, feeding on mostly plants and grasses. Like their larger kangaroo relatives, they’re marsupials, or mammals with pouches into which newborns crawl for further development.

In his 30 years on the job, Rogers says this was about the fourth time he’s come across a kangaroo or wallaby.