Bandicoots, the little marsupial diggers

 

Bandicoots are fascinating creatures, but I suspect few people outside Australia and New Guinea have ever heard of them, well, unless you count Crash Bandicoot…

They are probably best known in suburban Australia for infuriating gardeners with the conical pits, or “snout-pokes”, they dig whilst foraging for their food, which varies a little among species but usually includes fungi, plants and invertebrates. All Australian bandicoots are diggers, and a recent study estimated that a single southern brown bandicoot could dig as many as 45 foraging pits each day, meaning it has the potential to excavate around 3.9 tonnes of soil each year! That’s not bad for an animal that weighs less than 2 kilograms.

A long-nosed bandicoot (Perameles nasuta) eyeing up my dinner at a National Parks campsite in New South Wales. Photo credit Anna MacDonald.

In the not too distant past, bandicoots and their relatives could be found across almost the entire Australian continent, but theirs has been a sad story of extinction and decline since Europeans arrived. Today, thanks to habitat loss, competition from introduced rabbits, and predation by introduced cats and foxes (check out this camera trap photo, captured by Guy Ballard, of a feral cat with a bandicoot), many populations have diminished or disappeared. This may have real implications for the ecology of Australia: digging mammals seem to have important roles in soil turnover, water and nutrient cycling, and seedling recruitment, and the decline of these little diggers may have caused a deterioration in ecosystem function across the Australian continent.

There is an awful lot more I could share about bandicoot ecology and evolution, but for now I want to concentrate on explaining what a bandicoot is, how many species there are, and where in the world they are found. I hope you’ll agree with me that as well as being amazingly cute (the official term is “bandicute”) they are also amazingly interesting.

So, bandicoots are small-medium sized marsupials. In fact, they are the only group of marsupials that develop a chorio-allantoic placenta, like that seen in eutherian mammals, during pregnancy. Bandicoots are classified taxonomically as members of the order Peramelemorphia. This order consists (or consisted) of three families.

Family Chaeropodidae – the pig-footed bandicoot

The pig-footed bandicoot. Image after John Gould [Public domain] via Wikimedia Commons.

The pig-footed bandicoot was the only member of the family Chaeropodidae. It lived across much of arid and semi-arid Australia, but likely became extinct in the early 1900s. Illustrations by Gould portray it as a very dainty bandicoot. Its scientific name is Chaeropus ecaudatus, which means “pig-foot” and “tail-less”. The latter part of the name is misleading: although the first specimen described by scientists was missing the tail, this wasn’t actually normal for this species.

Family Thylacomyidae – the bilbies

The family Thylacomyidae is now represented by a single species, the greater bilby.

The greater bilby (Macrotis lagotis). Photo credit Bernard DUPONT [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)%5D via Wikimedia Commons.

One of the most notable things about the bilby’s appearance is its large ears. Its scientific name, Macrotis lagotis, even means “big-eared” and “hare-eared”. The bilby has been adopted as a symbol of Easter in Australia, where hares and rabbits are introduced pests. This species used to be found across 70% of mainland Australia, but it now has a very restricted distribution and is listed as Vulnerable by the IUCN.The bilby is a conservation icon in Australia, and the Australian Wildlife Conservancy has recently proposed new plans to exclude feral cats from a large section of Diamantina National Park, to protect bilbies and night parrots. This might stop the greater bilby going extinct like its cousin, the lesser bilby (Macrotis leucura = “white-tailed”), which was an Australian desert species last recorded by scientists in 1931.

Another bilby photo, because why not! Photo credit Judy Dunlop.

 

Family Peramelidae – all the other bandicoots

The family Peramelidae is the largest bandicoot family and includes several Australian species as well as a range of bandicoots that live in New Guinea (in Papua New Guinea and in Indonesian territories) and on nearby islands. I have to confess that I know very little about the non-Australian bandicoots, which I think means it is time for me to do some homework. To help us understand how the different species are related to one another, we can further divide this family into several sub-families.

Peramelinae

The sub-family Peramelinae includes two distinct types of bandicoot: the “brown bandicoots”  in the genus Isoodon (which means “equal-toothed”) and the “long-nosed bandicoots” in the genus Perameles (which means “pouched-badger”). These are the bandicoots most commonly seen in Australia.

A southern brown bandicoot (Isoodon obesulus) enjoying a scavenged meal of bacon rinds in a Tasmanian pub car park – never let it be said that these are not classy creatures! Photo credit Anna MacDonald.

The southern brown bandicoot (Isoodon obesulus – obesulus denotes that this is a “plump” bandicoot) was abundant and widespread but now has a fragmented distribution with some threatened populations. We still don’t fully understand the relationships among different populations of the southern brown bandicoot, which can be morphologically varied. Several subspecies are recognised, but genetic data now suggest that we might need to revise the way some of these are managed… more on that next year perhaps…

The golden bandicoot (Isoodon auratus). As you can see, there are many similarities with the southern brown bandicoot. Photo credit Judy Dunlop.

The golden bandicoot (Isoodon auratus – auratus refers to the golden colour of its fur) is listed by the IUCN as vulnerable and is now restricted to less than 1% of its pre-European range. Interestingly, recent research has found strong genetic similarities between the golden bandicoot and some populations of the southern brown bandicoot… but we’re not exactly sure what the implications of this are yet.

The northern brown bandicoot (Isoodon macrourus – macrourus means “big-tailed”) is common and widespread across much of northern and eastern Australia, as well as parts of New Guinea, but it has declined in some areas. An absolutely fascinating observation from this species is that the Y chromosome is eliminated from cells in some parts of the body in male northern brown bandicoots!

The western barred bandicoot (Perameles bougainville). Photo credit Judy Dunlop.

The western barred bandicoot (Perameles bougainville – named after the French navigator Baron de Bougainville) was once widespread in southern Australia, but this species is now endangered. It remains on two offshore islands in Western Australia and has been reintroduced to some mainland reserves where it is protected by predator-proof fences.

The eastern barred bandicoot (Perameles gunnii – named after the naturalist Ronald Gunn), is probably my favourite of all the bandicoot species (but shhh, don’t tell the others!). Check out the wonderful photos on its Arkive page – bandicute or what? It is fairly common in good habitat in Tasmania, but very recently became extinct in mainland Australia. Since then, this species has been reintroduced to protected reserves in Victoria, where fox and rabbits are controlled.

The long-nosed bandicoot (Perameles nasuta – nasuta refers to the “notable nose” of this bandicoot – see my photo at the start of this post), is still common and widespread in eastern Australia. Some interesting research found that long-nosed bandicoots actively avoided foraging in the gardens of homes with dogs, suggesting that they recognise the threat posed by this predator because of their co-evolution with dingoes over several thousand years. In contrast the bandicoots did not avoid gardens with cats, which arrived in Australia much more recently.

Edited 10/06/2016: in exciting news, recent research has now revealed another long-nosed bandicoot species! Previously, Perameles nasuta was divided into two subspecies, P. n. nasuta and P. n. pallescens, with the latter found only in northern Queensland. New work on morphological and genetic differences between these subspecies now supports raising P. n. pallescens to the species level in its own right. This new bandicoot species will be known as the northern long-nosed bandicoot, Perameles pallescens.

The desert bandicoot (Perameles eremiana – eremiana is derived from the Latin word “eremus”, which means desert) sounds like it was a really interesting animal, but very little is known about it. It likely became extinct between the late 1940s and 1960s. Even the cause of this extinction is uncertain – it may have been because of the arrival of foxes and cats, or because of changes to fire regimes in its habitat.

Echymiperinae

The sub-family Echymiperinae is the most speciose (and the most difficult to pronounce). Two genera are found only in New Guinea and nearby islands: these include the endangered Seram bandicoot (Rhynchomeles prattorum) and four species in the genus Microperoryctes: the Arfak Pygmy Bandicoot (Microperoryctes aplini), the mouse bandicoot (Microperoryctes murina), the striped bandicoot (Microperoryctes longicauda) and the Papuan bandicoot (Microperoryctes papuensis). The striped and Papuan bandicoots seem to be fairly stable from a conservation perspective, but the mouse and Arfak pygmy bandicoots are both classed by the IUCN as “data deficient”. This basically means that we don’t know enough about them to know whether or not they are endangered!

The rufous spiny bandicoot (Echymipera rufescens). Photo by Michael Pennay (CC BY-NC-ND) https://www.flickr.com/photos/37577693@N04/3575602052/

In addition, the Echymiperinae includes five species in the genus Echymipera. The rufous spiny bandicoot (Echymipera rufescens, which means “spiny pouched animal” and “reddish”), is the only member of the Echymiperinae to live in Australia, where it is restricted to the Cape York Peninsula in far north Queensland. It also occurs in New Guinea, along with the common echymipera (Echymipera kalubu) , Clara’s echymipera (Echymipera clara), David’s echymipera (Echymipera davidi)  , which is endangered, and Menzies’ echymipera (Echymipera echinista), which is classed as data deficient.

Peroryctinae

Finally, there are two species in the sub-family Peroryctinae: the endangered giant bandicoot (Peroryctes broadbenti) and Raffray’s Bandicoot (Peroryctes raffrayana). These are both restricted to New Guinea and that’s about all I know. I am going to make sure I learn more about these species ASAP!

 

• Edited 19/05/2016 to include some wonderful photos shared by Judy Dunlop (@fudgeh0g). If you like them, you should follow her adventures in Western Australian wildlife conservation on Twitter!
• Edited 10/06/2016 to include information about the newly-recognised northern long-nosed bandicoot.