Field biology of the platypus (Ornithorhynchus anatinus): historical and current perspectives

Abstract

The ¢eld biology of the platypus, Ornithorhynchus anatinus, was ¢rst studied by a number of expatriate biologists who visited the Australian colonies to collect specimens in the 1800s. Their work was followed in the early to mid-1900s by a group of resident natural historians and later by an increasing number of academic biologists. All of these workers contributed signi¢cantly to the current understanding of the ¢eld biology of this unique Australian species. The platypus occupies much the same general distribution as it did prior to European occupation of Australia, except for its loss from the state of South Australia. However, local changes and fragmentation of distribution due to human modi¢cation of its habitat are documented. The species currently inhabits eastern Australia from around Cooktown in the north to Tasmania in the south. Although not found in the west-£owing rivers of northern Queensland, it inhabits the upper reaches of rivers £owing to the west and north of the dividing ranges in the south of the state and in New South Wales and Victoria. Its current and historical abundance, however, is less well known and it has probably declined in numbers, although still being considered as common over most of its current range. The species was extensively hunted for its fur until around this turn of this century. The platypus is mostly nocturnal in its foraging activities, being predominantly an opportunistic carnivore of benthic invertebrates. The species is homeothermic, maintaining its low body temperature (32 8C), even while foraging for hours in water below 5 8C. Its major habitat requirements include both riverine and riparian features which maintain a supply of benthic prey species and consolidated banks into which resting and nesting burrows can be excavated. The species exhibits a single breeding season, with mating occurring in late winter or spring and young ¢rst emerging into the water after 3^4 months of nurture by the lactating females in the nesting burrows. Natural history observations, mark and recapture studies and preliminary investigations of population genetics indicate the possibility of resident and transient members of populations and suggest a polygynous mating system. Recent ¢eld studies have largely con¢rmed and extended the work of the early biologists and natural historians.

High levels of genetic divergence between Tasmanian and Victorian platypuses, Ornithorhynchus anatinus, as revealed by microsatellite loci

“…This semi-aquatic monotreme is confined to inland waterways and its distribution is largely restricted to the east coast of Australia ( Fig. 1) from Cooktown in the north to Tasmania in the south (Grant and Temple-Smith 1998). Despite being listed as common throughout their range, platypuses are still considered potentially vulnerable (Carrick 1983).…”

The platypusOrnithorhynchus anatinusin headwater streams, and effects of pre-Code forest clearfelling, in the South Esk River catchment, Tasmania, Australia

“…Key elements of 'ideal' platypus habitat, summarised by Grant and Temple-Smith (1998), were observed in the relatively undisturbed first order streams: banks consolidated by the roots of native plant species with overhanging foliage, a diversity of 'in-stream' habitats, including aquatic vegetation, 'in-stream' logs, and a series of distinct shallow pools, with little sand accumulation, and separated by cobbled riffle areas. Many of these habitat features were lost or reduced in the streams that had been disturbed in the past by the clearfelling, burn and sow practice.…”

Morphological and Histochemical Observations on the Crural Gland-Spur Apparatus of the Echidna <i>(Tachyglossus aculeatus)</i> together with Comparative Observations on the Femoral Gland-Spur Apparatus of the Duckbilled Platypus <i>(Ornithorhyncus anatinus)</i>

“…Temple-Smith [1973] hypothesizes that at this time, the femoral gland-spur complex is used as a mechanism for spatial separation of male platypuses along river habitat during the breeding season. Further field studies of the platypus support this view [Grant, 1995;Grant and Temple-Smith, 1998]. …”