BETTONGS

Tasmanian Bettong (Bettongia gaimardi) x Brush-tailed Bettong/Woylie (Bettongia penicillata – reported as Hypsiprymnus ogilbyi) – 3 hybrids were bred at Regents Park Zoo (London Zoo) in the 1870s. Bettongs are small marsupials, Tasmanian Bettongs are a subspecies of the Eastern Bettong.
An alleged cross between the Tasmanian Bettong and a kangaroo was reported in Tasmania in 1937, but the size differential makes this unlikely. The creature, a female, was half the size of an adult kangaroo (species not specified) with legs, eyes and mouth resembling a kangaroo rat, but a kangaroo-like head. The fur was kangaroo like on the nape of the neck, but much softer on the back. The taile was half-white, half-grey, and the legs and underparts were also white – markings similar to the Eastern Bettong, but not found on kangaroos or wallabies . The Bennett’s, or Red-necked, Wallaby (Macropus rufogriseus) is also found in the area, has soft fur and produces colour variants (e.g. albinos). The unusual creature was more likely a piebald/partial albino form of Bennett’s Wallaby than a hybrid.

KANGAROOS

The Western Grey Kangaroo (Macropus fuliginosus) x Eastern Grey Kangaroo (Macropus giganteus) – hybrids are not uncommon in captivity and the female hybrids are fertile. Female F1 hybrids preferred to mate with male Western grey Kangaroos and when their female progeny are also backcrossed to the West grey Kangaroo the F3 males may be fertile. A backcross of F1 female to a male Eastern Grey Kangaroo was monorchid (one testicle) and anopthalmic (no eyes). The two species also hybridise and backcross in the wild where they form mixed mobs. The Western Grey Kangaroo also hybridises with the Red Kangaroo (Megaleia rufa).

The Eastern Grey Kangaroo hybridises with the Red Kangaroo in captivity. Lord Rothschild had a collection of kangroos and wallabies that lived in a mixed group. His single female Red Kangaroo mated with a male Eastern Grey Kangaroo producing first a female hybrid and then a male hybrid that resembled the mother, the male hybrid being especially vivid in colour. A juvenile hybrid is displayed at the Natural History Museum in Tring which houses Rothschild’s collection of animals.

The Eastern Grey Kangaroo has formed hybrids with the Whiptail Wallaby and with the Common Wallaroo/Euro (Macropus robustus). Dublin Zoo had an Eastern Grey Kangaroo x Wallaroo hybrid in 1899. Historically, the Euro (M. r. erubescens) was considered distinct from the Common Wallaroo (M. r. robustus) and hybrids between the two were reported. They are now considered sub-species of the Common Wallaroo. The Red Kangaroo has also formed hybrids with the Common Wallaroo.

This photo of a hybrid between a red kangaroo (Macropus rufus)and a great grey kangaroo (Macropus giganteus) was taken at the Rothschild Zoological Museum in Tring. It was probably bred at the end of the 19th Century.

Over a 10 year period, Eastern and Western grey kangaroos were bred in enclosures. All western subspecies interbred freely. Western grey kangaroo males bred with Eastern grey kangaroo females and produced hybrid young. Eastern grey kangaroo males did not breed with Western grey kangaroo females. The male hybrids were sterile. The female were fertile and readily backcrossed with male western grey kangaroos. (Poole, WE "Reproduction in the Two Species of Grey Kangaroos, Macropus Giganteus Shaw and M. Fuliginosus (Desmarest). Ii. Gestation, Parturition and Pouch Life." Australian Journal of Zoology 23(3) 333 - 353 (1975))

TAMMARS AND PADEMELONS

Hybrids of Garden Island Tammars (Scrub Wallabies, Macropus eugenii) and Kangaroo Island Tammars have been bred. These wallabies have been physically separated for at least 10,000 years and, though classified as the same species and interfertile, have genetic differences. Hybrids of Tammar Wallaby and Pademelon (Thylogale sp. a small Wallaby-like marsupial) have also been attempted. (ARC Centre for Kangaroo Genomics: "Breeding marsupial hybrids to provide markers for mapping" by Marilyn Renfree, Des Cooper, Geoff Shaw, Cathy Herbert). To create hybrids, the young from one species must be transferred into the pouch of a mother from the other species (called cross-fostering). This imprints the young on the foster-species. In addition to cross-fostering, hybrids of Tammar Wallabies and and Parma (Macropus parma) were created using in-vitro fertilization. The hybrid embryos can be implanted into a female of either species.

Red-legged Pademelon (Thylogale stigmatica) x Red-necked Pademelon (Thylogale thetis) has hybridised in captivity.

TREE KANGAROOS

Doria’s Tree Kangaroo (Dendrolagus dorianus) x Ifola Tree Kangaroo (Dendrolagus notatus) may hybridise in a contact zone. Goodfellow’s Tree Kangaroo (Dendrolagus goodfellowi) x Matschie's(or Huon) Tree Kangaroo (Dendrolagus matschiei) have hybridised at the Cleveland Zoo in Ohio, and may hybridise in a contact zone. Grizzled Tree Kangaroo (Dendrolagus inustus) x Ursine Tree Kangaroo (Dendrolagus ursinus) have hybridised in captivity at Philadelphia Zoo in 1935.

WALLABIES

Grey Dorcopsis/Grey Forest Wallaby (Dorcopsis luctuosa) x Brown’s Pademelon (Thylogale browni) may formn hybrids in New Guinea where they are separated by a population of Macleay’s Dorcopsis/Papuan Forest Wallaby (Dorcopsulus macleayi) which is intermediate in appearance.

Agile Wallaby (Macropus agilis) x Red Kangaroo (Megaleia rufa) have produced hybrids of both sexes. Agile Wallaby (Macropus agilis) x Red-necked Wallaby (Macropus rufogriseus) have formed hybrids. Agile Wallaby (Macropus agilis, formerly Protemnodon agilis) x Swamp Wallaby (Wallabia bicolor formerly Protemnodon bicolor) produced 5 hybris at london Zoo in the 1960s. The Black-striped Wallaby (Macropus dorsalis) which appears extinct in the wild has formed hybrids with both the Tammar Wallaby (Macropus eugenii) and the Parma Wallaby (Macropus parma). The Tammar Wallaby has hybridised with the Parma Wallaby and with the Swamp Wallaby.

Male Bennett’s/Red-Necked Wallabies have hybridised with the Red-necked Pademelon (Thylogale thetis) in captivity. The hybrid at Frankfurt Zoo resembled the Pademelon mother. Female Bennett’s/Red-Necked Wallabies will hybridise with male Swamp Wallabies.

The Allied Rock-wallaby (Petrogale assimilis) forms part of the P. lateralis (Black-flanked Rock-wallaby/P. penicillata (Brush-tailed Rock-Wallaby) species complex, including Herbert's rock-wallaby (P. herberti), Godman's rock-wallaby (P. godmani), the Mareeba rock-wallaby (P. mareeba) and the Mount Claro rock-wallaby (P. sharmani), and these interbreed where their ranges overlap. In many cases the females are fertile, but the males are infertile or poorly fertile. The following hybrids have been recorded:

Allied Rock-wallaby × Unadorned Rock-wallaby (Petrogale inornata), Allied Rock-wallaby × Mareeba Rock-wallaby (P. mareeba), Allied Rock-wallaby x Mareeba Rock-wallaby x Brush-tailed Rock-Wallaby (3-way hybrid), Allied Rock-wallaby x Sharman’s Rock-wallaby (P. sharmani), Godman’s Rock-wallaby (P. godmani) x Mareeba Rock-wallaby, Godman’s Rock-wallaby X Purple-necked Rock-wallaby (P. purpureicollis), Brush-tailed Rock-wallaby x Herbert’s Rock-wallaby (P. herberti), Unadorned Rock-wallaby x Purple-necked Rock-wallaby, Black-flanked Rock-wallaby (P. lateralis) x Purple-necked Rock-wallaby, Mareeba Rock-wallaby x Sharman’s Rock-wallaby, Brush-tailed Rock-wallaby x Purple-necked Rock-wallaby.

Hybrids between the Cape York Rock Wallaby (P. coenensis) and Godman’s Rock-wallaby are suspected. The Black-flanked Rock-wallaby] can hybridise with Rothschild’s Wallaby (P. rothschildi). The Proserpine Rock-wallaby (P. Persephone) produced a female hybrid with the Yellow-footed Rock-wallaby (P. xanthopus).

Several wallaby or wallaby/kangaroo hybrids have been experimentally bred. The male parent is given first:

- Hill wallaroo (Macropus robustus) X red kangaroo (M rufus) produced an infertile female hybrid with only one ovary
- Swamp/Black wallaby (Wallabia bicolor) X Red-necked wallaby (M rufogriseus) produced a sterile male hybrid
- Agile wallaby (M agilis) X Red-necked wallaby (M rufogriseus) produced a sterile male hybrid
- Tammar Wallaby (M eugenii) X Black striped wallaby (M dorsalis) produced a sterile male hybrid

All of the above hybrids showed a mix of traits from both parents and all were found to be sterile (the female may have been so poorly fertile as to be considered sterile). Although the males had testes, they did not produce sperm and some were found to have Y-chromosome abnormalities. (MJ Smith, DL Hayman and RM Hope, "Observations on the chromosomes and reproductive systems of four macropodine interspecific hybrids" Australian Journal of Zoology 27(6) 959 - 972 (1979))

Hybrids have also been bred from male red kangaroo X female wallaroo and, based on the research of Smith, Hayman and Hope, are assumed to be sterile.

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