Common Hamster and Golden Hamster have mated and resulted in pregnancy in a Female Golden Hamster, but no offspring were born. Golden Hamsters and Romanian Hamsters produce sterile hybrid offspring which are intermediate in type. Campbell's Dwarf Russian Hamster hybridizes freely with the Siberian Hamster (Winter White Russian Dwarf Hamster) and produces fertile hybrid offspring; these may be sub-species. Norway (Brown) Rats and Black Rats will mate and will produce live offspring, but the offspring die shortly after birth. Among the Jirds (a type of gerbil), many of the Shaw's Jirds kept as pets in the UK are apparently hybrids between the Shaw's Jird and Libyan Jird (they are known as UK Shaw's Jirds to differentiate them from the true species). Hybrids exist between the Pallid Gerbil and Cheesman's Gerbil. Although rodent fanciers may deplore the hybrid strains or try to segregate the species, nature is not always observant of human-declared species boundaries!

For those interested in laboratory rodents, there are also natural and artificial hybrids between different European mice (Mus musculus x M domesticus, M musculus x M castaneus) and laboratory hybrids between mice (M musculus x M spretus, M musculus x M spicilegus, M musculus x M macedonicus) However other mice could not hybridise with M musculus. M musculus x M caroli hybrids were either stillborn or failed to thrive after birth. M musculus x M cervicolor did not get beyond early embryo cell divisions. M musculus x M dunni also failed early in embryo development. Of those mouse hybrids that thrived, the male was sterile, but the female was fertile. There are also hybrids between the East European Vole and Common Vole.

According to a publication in 1911, crosses were made between the common rabbit and the guinea-pig and were exhibited in the Zoological Gardens of Sydney, New South Wales. There have been several claims of rabbit/cavy (guinea pig) crosses since then.

In "The Variation Of Animals And Plants Under Domestication" Charles Darwin wrote: "But from what we hear of the marvellous success in France in rearing hybrids between the hare and rabbit (See Dr. P. Broca's interesting memoir on this subject in Brown-Sequard 'Journ. de. Phys.' volume 2 page 367.), it is possible, though not probable, from the great difficulty in making the first cross, that some of the larger races, which are coloured like the hare, may have been modified by crosses with this animal. Nevertheless, the chief differences in the skeletons of the several domestic breeds cannot, as we shall presently see, have been derived from a cross with the hare [...] The common hare [...] has crossed with the rabbit. (Although the existence of the Leporides, as described by Dr. Broca ('Journal de Phys.' tome 2 page 370), has been positively denied, yet Dr. Pigeaux ('Annals and Mag. of Nat. Hist.' volume 20 1867 page 75) affirms that the hare and rabbit have produced hybrids.)"

This appeared in The Field No 2887, April 25th, 1908: "Alleged Hare-Rabbit Cross - about four years ago, in reviewing a book on rabbits in the Zoologischer Garten, Dr Brettiger, the editor, drew attention to the lack of positive evidence on this subject. In the current number, Herr Elffe, of Hamburg, challenges the editor's view and describes what he believes to be cases of hybridity between the hare and the rabbit, and the fertility of some of the hybrids, which are said to breed twice in the eyar, and to throw blind, naked young. According to the author, the hybrid race was founded five years ago and some of [the animals] are said to be still living in Hamburg. In these circumstances, the matter seems to call for investigation." However, it was noted that Herr Elffe brought forth no evidence in support of his statements and that wild rabbits frequently bred with fancy rabbits.

Textual content is licensed under the GFDL.