| laboratory rat | 2.57 | Even laboratory rats eat something better than trail mix. | ||
| lab rat | 2.11 | Lab rats, relax. | ||
| gym rat | 1.38 | He is a gym rat with a purpose. | ||
| control rat | 0.66 | A group of control rats received no X-rays. | ||
| desert rat | 0.59 | A tasty desert rat maybe. | ||
| mall rat | 0.53 | The appeal of mall rats? | ||
| sewer rat | 0.46 | Sewer rats everywhere take righteous offense. | ||
| fibre rat | 0.39 | The higher fibre rats had eight testicular tumours and one mesenteric lesion. | ||
| river rat | 0.39 | Some residents call themselves river rats. | ||
| rug rat | 0.39 | And small children are known both as ankle-biters and rug rats. | ||
| diet rat | 0.33 | There was also a higher incidence of diverticulosis in the low fibre diet rats. | ||
| rubber rat | 0.33 | Fancy a rubber rat? | ||
| mother rat | 0.26 | The space agency believes the rats grew listless because the mother rats became dehydrated and were unable to nurse. | ||
| rink rat | 0.26 | Not what a rink rat wants. | ||
| roof rat | 0.26 | Left unchecked, roof rats can develop rat communities with officious homeowners associations. |