This article is reprinted from Thylacinus Vol. 12 No. 1 1987 and is used with kind permission of the Australasian Society of Zoo Keepers.  (Thylacinus is the quarterly journal published by the A.S.Z.K.)

Registrants at the 1986 A.S.Z.K. Conference who traveled to Healesville Sanctuary may remember this presentation by Gary Slater, the Sanctuary’s Keeper in Charge of the Nocturnal Section.    Described in 1980, the Long-footed Potoroo is an important addition to Victoria’s recorded fauna.

History

In June 1967, a female Potoroo with early pouch young was caught in a dog trap near Bonang in East Gippsland, Victoria, but died soon after capture due to injuries inflicted by the trap. The following year and adult Potoroo was found dead on the Princes Highway near Bellbird, also in East Gippsland. At the time it was suspected that both animals were a distinct species from the Long-nosed Potoroo, Potorous tridactylus. Attempts to trap live specimens at both sites proved unsuccessful for ten years until April 1978 when two animals, an adult female and a slightly younger male, were trapped at the Bellbird site. This was followed six months later by the capture of two adult females also at the Bellbird site. All animals were held for study and examination by the Fisheries and Wildlife Division’s Senior Research Officer, J.H. Seebeck who, together with P.G. Johnston of Macquarie University, described in 1980 the captured specimens as a new species - the Long- footed Potoroo, Potorous longipes (Seebeck and Johnston, 1980). The road kill specimen was lodged with the Museum of Victoria as the nominated holotype (permanent reference for the species). The male and female trapped in 1978 were nominated as paratypes (other specimens of the species for permanent reference).
Of these two animals, the female was retained by the Fisheries and Wildlife Service for further study, while the male and females subsequently captured were transferred to Healesville Sanctuary’s Small Mammal Breeding Pens to start a breeding program. The female paratype was incorporated into the program in 1981.

Distribution and Habitat

The geographic range of Potorous longipes cannot be
delineated as yet. Both species of Potorous have been trapped within l0krns of each other (fig.1), and broad scale vegetation mapping of the area does not show any disjunction between sites, which suggests that their range could be sympatric (Seebeck and Johnston, 1980).  Bonang and Bellbird have an average rainfall of 1100mm - 1200mm. per year.   These sites contain open forests with a mixture of Eucalypt species and a dense under-story of schlerophylous shrubs. A dense layer of wire grass, ferns and sedges forms the ground cover.
Bellbird is 150m above sea level and is subject to frosts during the winter months. Bonang is 600m above sea level and has frequent snowfalls during winter.
 

DESCRIPTION
It was confirmed that the species was distinct from P. tridactylus when the first two specimens trapped were karyotyped and were shown to have 24 chromosomes in both sexes in comparison to P. tridactylus which has 12 in the female and 13 in the male (Seebeck and Johnston, 1350).    These species also differ in their cranial morphology (fig.2) and electrophoretic properties.

Visually one needs to look, as the name refers, at the animal’s hind foot which is longer in measurement than the head and proportionally longer than in other species (Seebeck, 1983).   Another easily discernable feature is its larger size, which is 15% heavier than the largest P. tridactylus recorded and 100% than any recorded in Victoria. The tail commensurate with body size is much thicker.
 

Housing

Healesville Sanctuary’s Small Mammal Breeding Pens are a steel tube-framed construction covered in 10mm X 25mm weldmesh.   An 800mm tin panel at ground level surrounds each of the 23 pens. This forms a visual barrier to occupants in adjoining pens. A service corridor runs the length of the construction with pens in varying sizes from 3m X 12m, 4m X l0m and 3m X l0m on each side.   Entry is gained by a standard sized ply door.   The walls adjoining the corridor are clad in A.C. sheeting to offer the animals’ greater privacy.   A small weldmesh viewing panel is available for observations.   During summer, shade cloth is placed over half the enclosure for sun protection and on days of excessive heat, overhead sprinklers are used intermittently. Heat is provided during winter months by means of concrete heat pads.

All pens have tussocks (Lomanodras longifolia) planted throughout which are favoured by the animals to dig small squats at the base. The squats are lined by the animal with grass hay, supplied fresh weekly, to form a nest. Only recently we have observed, for what is believed to be the first time, a P. longipes gather hay by mouth then transfer it to the tail for carrying to the nest site in the same manner as a Brush-tailed Bettong. Each pen may contain a number of nesting sites which would all be used at some period during the week (pers. obs.). Potoroos seem to be communal in captivity, with all animals penned together sharing the same nest where they will sit with their backs to the tussocks and only their noses visibly protruding from the nest.

Various sized logs and stumps are supplied and utilised by the animal to gain a vantage point to observe its surroundings. Where Potoroos share accommodation with an arboreal species, such as Ground Cuscus, the branches used can be quite large and reach ground level. Observations have been made of P. longipes using these branches to climb a height of at least 1.5m with reasonable balance and agility. They could quite feasibly escape by climbing the wire if the pens were not enclosed (J. Seebeck, pers. comm.). We have not housed P. longipes with any other terrestrial species but housing compatibility with arboreal species such as Sugar or Squirrel Gliders, Leadbeater’s and Ringtail Possums and Ground Cuscus presents few problems.

Diet

 
Very little is known of P. longipes diet in the wild but it is probably similar to P. tridactylus as they both dig the same characteristic conical pits in search of root tubers, fungi, insects and their larvae (Seebeck, 1983). The different articulation of the lower jaw of P. longipes possibly reflects some variation in diet. At Healesville, all Potoroos are fed a basic daily allowance of chipped apple and carrot, slices of orange and banana, greens such as lettuce, endive or silverbeet and a few pieces of dog chow. This is supplemented on a daily rotational basis with almonds, sunflower seeds, sultanas, raisins, cheese and hard boiled egg. When in season, additional fruits and vegetables such as corn, sweet potato, grapes and berries are offered. An important element to the diet is a half slice of bread soaked in cows’ milk enriched with Vitamin E drops and infant multivitamin drops. This appears to be the favoured food item, so adding any treatments required to the milk formula is an ideal form of administration.

Fresh water, grass hay, macropod pellets and, a mineralised salt block are available at all times.  The diet appears to be very fattening but we have not encountered any problems with weight control.   Constant monitoring of animals has ensured optimum weights of approximately 2.1kgs for males and 1.7kgs for females (Seebeck, 1983).

Observations have been made of P. longipes regurgitating food and then re-eating it for no apparent reason. There is no discernable food items in the regurgitation and it is similar in appearance to very loose faeces.

Management

The initial four specimens received were identified by means of ear tattoos, but reading these is difficult and subject to some confusion, metal tags have since been adopted. These are numbered metal bird wing tags (National Band and Tag Co. U.S.A.) applied by pliers to a pre-punched hole in the ear. Pre-punching a hole is preferred to pushing the tag straight through the ear as movement around the hole keeps the tag and ear free of dirt and healing tissue. Juvenile animals are usually tagged on independence.

Capture can be difficult as Potoroos are extremely agile and can stop or change direction very quickly. A 400cm hoop net with a light hessian sack attached is used for the capture. The animal is then transferred to a heavier sack for handling. Most animals are easily tractable during restraint although excessive hair is normally experienced (pers. obs.). This has little or no effect on the animal.

Vocalisation is restricted a slight whimper when being handled and a low ‘kiss-kiss or clicking sound when under stress or between mother and offspring (Seebeck, 1983).   When agitated or excited, the familiar tail swishing from side to side as seen in, for example, the Parma Wallaby and the Brush-tailed Bettong, can be observed.   Aggression between animals has been noted between two males housed together even though they still used the same nest, and a female and offspring which was at heal. Although no apparent reason for this aggression was discernable, subsequent young to this female have not encountered any problems. Two unrelated females were paired with a single male on two occasions but one female gained dominance over the other and had to be separated to avoid injury to the subordinate animal.

In captivity, Potoroos have been recorded as having coccidia and nematodes in the faeces, though no deaths have been attributed to these.

A single male has been put on display in the Sanctuary’s Nocturnal House which has made closer observation easier.  However, observations are usually restricted to a weekly stirring of animals from nest sites to count and check the animal’s condition. All pens are cleaned on a daily basis and on these occasions animals are rarely seen.

Breeding

 
As with most other aspects of this species, very little is known of its breeding behaviour.

Currently we maintain 7 males and 4 females, of which two are second generation captive bred. This breeding success enables us to confidently predict the continuation of the species in captivity and so prepare the strategies which ensure levels of inbreeding are kept to a minimum. The longer term may see inbreeding unavoidable as all current progeny are descendants of the original male captured.

Four nipples are present in the pouch but one young per annum seems to be normal, with pouch life being approximately 5 to 6 months (pers. obs.). The oestrus cycle and length of gestation are still unknown.

The first four recorded births were in February, July and September, which suggested non seasonal breeding. However, subsequent births in mid year, with young leaving the pouch between November and February, indicate the earlier pattern was probably influenced by the rotation of the breeding male between females.

The loss of early pouch young (fig.3) could have been due to stress caused by frequent handling or via some external influence such as foxes or cats.

Figure 3. Geniology of Long-footed Potoroo at Healesville Sanctuary (W.C. = wild caught, P.Y. = Pouch Young, male in squares, female in circles, diagonal lines = death)

The Future

In captivity we can, as was mentioned earlier, reasonably expect the species to continue breeding at its present rate, and thus with the influx of wild bred animals to expand the gene pool, a secure future looks assured.

Research into the species is a high priority and to this end the animals are made available for non damaging projects such as chromosomal studies on ear tissue sample, testing radio tracking collars, hair sample traps and subject-specific traps for use in field survey work.

The dispersal of stock to other establishments, as breeding allows, to prevent the possibility of disease or other calamity decimating the colony, is considered very desirable and we hope to do this in the not too distant future. We are currently readying a male and cycling female for transferal to the Arthur Rylah Institute for further research.

Conservation of the species in the wild seems less secure.  To date there have been no significant conservation measures undertaken apart from continuing survey of the areas. Forests adjoining the known sites are subject by land tenure to timber extraction in the near future (Seebeck, 1983) which will make F. longipes survival in the wild extremely precarious.

Acknowledgements

I would like to thank the following Healesville Sanctuary staff - K. Mason and J. Alexander for observations and many useful suggestions; Dr. David Middleton for veterinary advice; N. Morley for editing and C. Srb for typing.

References

 
Seebeck, J.H. and P.G. Johnston (1980) Potorous longipes (Marsupialia: Macropodidae), a new species from Eastern Victoria. Aust. J. Zool. 28: 119-34.
Seebeck, J.H. (1983) The Long-footed Potoroo. In, Strahan, R. (ed.) (1983) The Australian Museum Complete book of Australian Mammals. Angus and Robertson, Melbourne: 183.

Further Reading

Ahern, L.D. (1982) Threatened Wildlife in Victoria and Issues related to its Conservation. Fisheries and Wildlife, Victoria, Paper No. 27.

Collins L.R. (1973) Monotremes and Marsupials: A Reference for Zoological Institutions (Genus Potoroo). Smithsonian Institution Press, Washington, D.C. : 239-244.
Johnston P.G. and G.B. Sharman (1977) Studies on population of Potoroos desitiarest (Marsupilia) 1. Morphological Variation. Aust. J. Zool. 24: 573-588.

Poole W.E. (1979) The Status of Australian Macropodidae. In,
Tyler, N.J. (ed.) (1979) The Status of Endangered Australasian Wildlife, The Royal Zoological Society of South Australia, Adelaide: 13-27.

Seebeck J.H. (1979) Long-nosed Potoroo (Potorous tridactylus), Husbandry and Management of a Captive Colony. In, Evans, D.D. (ed.) (1982) The management of Australian Animals in Captivity, Zoological Board of Victoria, Melbourne.

Thornback, J. and H. Jenkins (1982) The I.U.C.N. Mammal Red Data Book, Part 1. I.U.C.N., Morges, Switzerland.