CHAPTER IX. Distribution and Haunts

DISTRIBUTION AND HAUNTS

The platypus is confined to that part of Australia which lies east of 138° E. long., and to Tasmania. It has not so far been recorded from the Cape York Peninsula north of 15° S. lat.; but this country is little known, and it is not improbable that the animal will be found there when the rivers are examined. The most northerly rivers from which we have definite records are the Mitchell and its tributaries on the western side, and the Barron on the east. A number of rivers farther to the north--such as the Coleman, Archer, and Batavia, running into the Gulf of Carpentaria, and the Normanby and Kennedy rivers entering Princess Charlotte Bay--are probably suitable as habitats, and may in time be found to contain Ornithorhynchus.

The first record of the platypus in the Gulf rivers is given by Armit (1878, p. 413). He observed one swimming in a large water-hole 150 miles west of Georgetown on the road to Normanton. It is not clear whether this water-hole was part of a river bed; but it could not, in any case, have been far away from the Gilbert River, along which the road runs. He also stated that platypus occurred in the Leichhardt River, which is the most westerly record. Waite (1896) published records from the Norman River at Normanton on the Gulf side, and from the Barron, Herbert, and Burdekin rivers on the east coast. Through the kindness of Mr. H. A. Longman, of the Queensland Museum, Mr. A. H. Chisholm, and a number of other correspondents, I have gathered a considerable series of records for Queensland waters. The platypus is exceedingly plentiful in the upper waters of the Mitchell and its tributaries, in the Barron, and the Herbert, especially on the tableland. It is also common enough in the small creeks draining into the Herbert below the range. It would seem to be almost equally plentiful in all the chief coastal river systems to the south--Burdekin, Fitzroy, Burnett, and Mary--although it is not so frequently seen in the more closely settled portions of the river valleys. No platypus has ever been seen (so far as I can ascertain) in the Diamantina and Cooper’s Creek, which drain into the interior; nor can I find any records for the Paroo and Warrego. They are found, however, in the Condamine, Macintyre, and Dumaresq rivers, and a tributary of the last is named the Mole River from the occurrence of the duck-mole in it. It was, indeed, on this stream that Caldwell collected some of his material. Mr. Longman mentions that his Museum has records of platypus from the Brisbane district in the early days, but none of recent date.

In New South Wales Ornithorhynchus is found in the upper waters of all the rivers draining to the east coast, and even in small creeks such as Ourimbah Creek, north of Gosford. It is especially numerous in the trout streams of the southern Alps, both those draining into the Murray system, and those running southwards into the Snowy. Inland, the records cover the upper waters of the Gwydir, Namoi, Castlereagh, and Macquarie in the north, but not the Bogan. In the south, the upper waters of the Lachlan, Murrumbidgee, and Murray still hold a goodly store. It will be remembered that the first platypus was discovered in a lagoon off the Hawkesbury. Two correspondents of the Sydney Daily Telegraph mention the occurrence of the animal in swamps and ponds not directly connected with streams. Mr. C. R. Stranger, writing from Curlewis, states that, when the great drought broke in June and July of 1920, the Curlewis swamp, which had been dry for several years, filled. Soon afterwards a platypus was seen in the swamp, and was there for a considerable time, always about the one spot. The swamp was four or five miles from the nearest stream, the Mooki River, though the two waters may have been connected by a backwater during the flood. Mr. George Boyd has often seen platypus in swamp lagoons of a permanent nature, situated in the neighbourhood of Wyong Creek but not connected with it except in times of flood. A third correspondent describes the finding of a platypus, after a thunderstorm, in a small water-hole in the rocks near the top of Black Mountain, a few miles from Dundee, and three or four miles from the nearest permanent water.

Krefft in his Catalogue of Mammals in the Australian Museum (1864) records three females in spirits from the Botanic Gardens; but these, if taken from the ponds, must have been previously released in them. He also records an adult male from North Shore, Sydney, and a female from George’s River, from both of which places they have long since disappeared. The upper reaches of the Nepean and its tributaries are, however, still tenanted, so that the platypus still occurs fairly close to Sydney.

The Victorian records include most of the southern tributaries of the Murray system, such as the Campaspe, Loddon, and Avoca rivers. The Snowy River, to the east, has already been mentioned. Kershaw made his observations upon the Hopkins in the west, and there are records from the Glenelg, close to the South Australian border. Mr. Noel Learmonth, writing to the Australasian (30 June, 1923), comments on the fact that the platypus is absent from the Eumeralla, Darlots, and Fitzroy rivers, though inhabiting the Wannon on one side and the Hopkins on the other. Mr. E. R. Waite, Director of the Adelaide Museum, has kindly supplied the known South Australian records--the Murray River at Murray Bridge and Tailem Bend, the Onkaparinga River, and the Glenelg, which just crosses into South Australia close to its mouth.

For information as to the distribution in Tasmania, I am indebted to Mr. Clive Lord, Director of the Tasmanian Museum and Art Gallery. He writes:--

“This species is generally distributed throughout Tasmania. From personal observation I can state that it can be found in most of the inland lakes that are not close to the settled areas. In certain of the National Park lakes (Mt. Field--20 miles NW. of Hobart) the platypus is numerous, and, as the area is an absolute sanctuary for our native fauna, it has a chance of living there in peace; but, despite the fact that the platypus is totally protected by law, they are very largely taken in other parts. At the Great Lake large numbers were captured for their skins, but we could not get a conviction. During the recent Christmas holidays I saw numbers in the lakes in the Cradle Mountain and Barn Bluffs district (NW. Tasmania). Along some of the rivers of the NW. coast the platypus is still to be found; but, generally speaking, the advance of settlement is reducing the number in the rivers, and the mountain lakes will be its stronghold in the future. There are numbers in Lake St. Clair, and, as previously noted, they frequent even the highest alpine lakes, over 3000 ft. above sea level.”

This sketch of its distribution shows that Ornithorhynchus is still widely spread throughout the eastern portion of the mainland and Tasmania, and is in no immediate danger of becoming extinct provided present laws are enforced. It is very probable that closer observation would discover its presence in many streams where its existence is wholly unsuspected, and it is remarkable that it has not been recorded from main rivers such as the Darling and Murray and the main channels of their larger tributaries, such as the Lachlan and Murrumbidgee. Although the creature seems partial to high places, it cannot be influenced altogether by altitude, for it occurs commonly throughout the low creeks and rivers of the coastal plain. Nor is rapidly running water essential, since the Tasmanian lakes are so well stocked. Certainly the platypus prefers clean, clear water, but it manages to survive quite comfortably in rivers like the Mary and the Burnett, which are far from being limpid streams. This, however, may be a matter of necessity, not of preference. It is probable that it finds a greater abundance of the food that most delights it in the more rapid waters of the upper stream. It may be, too, that the occurrence of large Murray cod (Oligorus macquariensis) in the larger rivers of the plains has something to do with the matter. The platypus, foraging blindly under water, or floating idly at the surface, would have no protection against these voracious creatures.

The hind legs are kept stationary to balance the buoyant body (or, to use a nautical phrase, to maintain an even keel). The one on the right is touching the sand with its muzzle, its right paw is fully extended, and the left is being brought forward for the next stroke. The finished stroke is shown by the position of the fore-paw (close to the body) of the one swimming on the left.

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The antiquity of the platypus, and the changes in river systems during the ages, render it probable that the animal inhabited at one time or another all the waters of Tasmania and of eastern Australia. Closer settlement is very likely responsible for its disappearance from certain rivers of the (Australian) coastal plain, and, as that area is not now subject to general flooding, it is hardly to be expected that the denuded rivers will ever be replenished with platypus by natural means.

That the platypus does travel over land is quite satisfactorily determined. But how far it can travel is not known. During floods it has to move about in search of food, and usually works towards the top of billabongs and backwaters, where supplies are more easily obtainable. As the waters recede, it is often left isolated in some deep water-hole, where it may continue to live happily for a time. Ultimately, however, it makes back to the main water, either by following the channel, or, if the river be nearer by another way, by cutting directly across country. I have observed this happening on many occasions, and have no doubt that the platypus possesses a highly-developed sense of direction, by means of which it makes straight for water. Animals released close to, but out of sight of, water, never hesitate; they make straight off towards the water closest at hand. In corroboration I quote the following paragraph from the Northern Daily Leader (Tamworth, N.S.W.) of 6 April, 1922:--

“The duck-billed platypus at times shows a remarkable knowledge of locality. I carried one in a bag from its native river, where it was caught on a night-line set for eels, to a shallow lake about a mile away. It was then gently slid into the water, but promptly swam ashore and started on the long crawl, straight for the home river. The duck-bill was recaptured and returned to the lake, which, it may be remarked, had no banks suitable for a platypus burrow. But again the animal swam out and made tracks for the old address. Eventually the beast was put far out in the lake and left to its own devices. A few days afterwards it was found dead in a patch of scrub about half-a-mile from the river in a direct line with the pool from which it was taken.”

The observations of correspondents indicate that the animal can cover a land distance of four or five miles, and may cross intervening high land. Since it has considerable powers of endurance, and, despite its voracious appetite, can survive without food for comparatively long periods, it is possible that it has managed to contrive its own distribution by direct means.

Platypus have often been observed working in a general direction either up or down stream. These movements are almost certainly influenced by food conditions. A migration of platypus was observed by the late Mr. William Hill in 1859, when he was manager of the Pallamallawa cattle station (now a township) on the Gwydir River. About fifty aborigines, under ‘King’ Binamoore, were camped on the river-bank not far from the homestead. One evening Mr. and Mrs. Hill strolled down to the camp for a yarn with Binamoore, who was an old friend, but the chat was interrupted by a sound from up river, similar to that made by a mob of cattle fording a stream. Always on the alert for movements of his herd, Mr. Hill, accompanied by his wife, walked down to the water’s edge to investigate. The river at the time was low, but still flowing, with occasional deep holes, connected by rapidly running shallows. Presently the noise was heard again, this time closer at hand, in fact so close that Binamoore and his tribe, and the tribal dogs, took fright, and bolted off to the next station, deserting their gunyahs. Mr. and Mrs. Hill then clearly observed a mob of platypus all swimming together at top speed with the current, and estimated that there were at least a hundred of them. There could be no doubt about the identification, as the animals were frequently obliged to expose themselves in climbing over obstructions in the shallows. On the following morning only an occasional platypus was to be seen, floating at the surface or swimming about in a leisurely way. I have every confidence in my informants, each of whom has repeated the story to me several times. I know of no other record of any mass movement of platypus, and my explanation is that the mob had gradually congregated from streams in which food supplies had been affected by flood, and were following the main channel in search of further supplies.

To anyone knowing the rivers and lakes mentioned in the records of distribution it will be obvious that the platypus inhabits a varied range of waters, from clear, icy, rapid alpine streams of the southern Alps to warm, turbid waters of the Queensland coastal plain, and from large lakes to small waterholes. Despite this apparent catholicity of taste there are certain conditions which determine the parts of these various waters chosen by the animal. The chief is that of abundant food supply.

Semon (1894, p. 10), who made careful observations on the Burnett, writes:--

“Ornithorhynchus anatinus inhabits the banks of running water within the area of distribution. It follows these from their source of origin down to the plains. The main condition for its occurrence is the scooping out of comparatively expansive depressions in the bed of the river, in which the water flows slowly, so that fine silt collects on the bottom and a vegetation of aquatic plants can develop, which serves as a resort for innumerable aquatic creatures, worms, crustaceans, larvae of insects, and molluscs. Here the Duckbill seeks its food, and hides from its hunter by diving. Here it can remain in periods of extended drought, which dry up the rest of the river bed, in a small amount of water. At such times those Duckbills which live in the smaller waterholes, so soon as the level of the water sinks too low, wander out into larger holes which are less likely to dry up. Then one notices an increase in the latter, and a coming together of the platypus folk.”

My own observations in the Manilla and New England districts confirm this statement. There the streams are partially blocked at frequent intervals by granite boulders, and a succession of quiet pools is formed between stretches of rapidly running water. In these pools the platypus finds its food. When freshes come down the river, however, coarse sand and gravel are deposited on the silt bottoms, and for a time the feeding-grounds are spoiled. At such times the animal is forced to seek for food where it may be found, and generally works its way upstream. After prolonged floods the animals are often found in considerable numbers dead upon the banks. This would seem to indicate that they had starved to death, but it must also be borne in mind that they dislike turbid water, and a continuance of disturbed conditions may have some physical effect upon them.

Heat and cold appear to have little effect, since the platypus seems equally at home in the warm streams of tropical northern Queensland and at a height of 6000 feet on the Kosciusko tableland--which, though not continuously snow-clad, nevertheless experiences falls of snow during the summer.

Note elevation of all except tail, which sometimes is hoisted also.

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Note powerful thrust of hind foot.

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