- Behavioural adjustments of wild-caught kangaroos to captivity
- Diets of mammalian herbivores in Australian arid, hilly shrublands: seasonal effects of overlap between euros (hill kangaroos), sheep and feral goats, and on dietary niche breadths and electivities
- Circadian variation in resource quality: leaf water content and its relevance to eastern grey kangaroo Macropus giganteus and common wombat Vombatus ursinus
- Dehydration, with and without heat, in kangaroos from mesic and arid habitats: different thermal responses including varying patterns in heterothermy in the field and laboratory.
- Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey kangaroo and red kangaroo
- Endogenous nitrogen excretion by red kangaroos (Macropus rufus): Effects of animal age and forage quality
- Energy requirements of the red kangaroo (Macropus rufus): impacts of age, growth and body size in a large desert-dwelling herbivore
- Field metabolic rate and water turnover of red kangaroos and sheep in an arid rangeland: an empirically derived dry-sheep-equivalent for kangaroos
- How important is milk for near-weaned red kangaroos (Macropus rufus) fed different forages?
- How kangaroos swim
- Hydrogen utilising bacteria from the forestomach of eastern grey (Macropus giganteus) and red (Macropus rufus) kangaroos
- Mechanistic explanations for drought-related mortality of juvenile red kangaroos; implications for population dynamics and modelling
- The effect of drought on kangaroo populations (PDF only)
- The genetic relatedness of a peri-urban population of eastern grey kangaroos
- The ecophysiology of survival in juvenile red kangaroos Macropus Rufus: greater demands and higher costs
- Unravelling methanogenesis in ruminants, horses and kangaroos: the links between gut anatomy, microbial biofilms and host immunity
- Ventilation patterns in red kangaroos (Macropus rufus Desmarest): juveniles work harder than adults at thermal extremes, but extract more oxygen per breath at thermoneutrality
- Walking on five legs: investigating tail use during slow gait
- Water metabolism and renal function and structure in eastern grey kangaroos (Macropus giganteus): responses to water deprivation
- Seasonal anoestrus in western grey kangaroos (Macropus fuliginosus ocydromus) in south-western Australia
- Inferring Kangaroo Phylogeny from Incongruent Nuclear and Mitochondrial Genes
- Marsupial genetics and genomics
- Thermoregulation by kangaroos from mesic and arid habitats: Influence of temperature on routes of heat loss in eastern grey kangaroos (Macropus giganteus) and red kangaroos (Macropus rufus)
(Munn, Phelan, Rigby, & Roberts, 2017)
This researched investigated the behaviour of wild-caught western grey kangaroos (Macropus fuliginosus) and red kangaroos (M.rufus) that were transferred to a large naturally vegetated enclosure. The research quantified feeding, moving, grooming and non-alert behaviours. Overall, the findings indicated that after 7-10 days wild-caught kangaroos adjusted to a novel environment and displayed behaviour patterns comparable with free-ranging counterparts.
Diets of mammalian herbivores in Australian arid, hilly shrublands: seasonal effects of overlap between euros (hill kangaroos), sheep and feral goats, and on dietary niche breadths and electivities
(Dawson & Ellis, 1996)
The diets of euros, domestic sheep and feral goats in hilly, shrub rangeland in southern Australia were examined in a 12-year study. Dietary overlap, foraging in relation to resource availability and the potential for competition in different conditions were also examined. This study found levels of dietary overlap to be low (lower than that of sheep and red kangaroos) even in periods of severe drought.
Circadian variation in resource quality: leaf water content and its relevance to eastern grey kangaroo Macropus giganteus and common wombat Vombatus ursinus
(Jarman & Evans, 2010)
This project considered leaf water content as a source of free water for leaf-grazing herbivores, eastern grey kangaroos and common wombats.
Dehydration, with and without heat, in kangaroos from mesic and arid habitats: different thermal responses including varying patterns in heterothermy in the field and laboratory.
(Dawson, Blaney, McCarron, & Maloney, 2007)
Field data showing the daily patterns in body temperature of kangaroos in hot, arid conditions, with and without water, indicate the use of adaptive heterothermy (large variation in body temperature). Variation was greater in the Eastern Grey, a species of mesic origin, than in the desert-adapted Red Kangaroo.
Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey kangaroo and red kangaroo
(Vendl, et al., 2015)
Research undertaken of 4 x red kangaroos and 6 western grey kangaroos to measure absolute CH4 production, CH4 per unit of dry matter, gross energy and digestible fibre. The absolute CH4 emissions of kangaroos in this study were similar to literature results and closely resembled those of other hindgut fermenters and ruminants. These researchers suggest that the apparent difference between macropods and ruminants is not due to a unique composition of the microbiome but rather to differences in the metabolic state of the microbiome.
Endogenous nitrogen excretion by red kangaroos (Macropus rufus): Effects of animal age and forage quality
(Munn, Dawson, & Hume, 2006)
This project compared how forage quality affected Nitrogen intake and excretion by YAF, weaned and mature non-lactating female red kangaroos. The findings support field observations that forage quality, and not just quantify, is a major factor affecting the mortality of juvenile red kangaroos during drought.
Energy requirements of the red kangaroo (Macropus rufus): impacts of age, growth and body size in a large desert-dwelling herbivore
(Munn & Dawson, 2003)
This research undertook to compare the resting metabolic rates (RMRs) and maintenance energy requirements (MERs) of young growing red kangaroos with adult animals. The data suggests that the proportionally higher RMR of juvenile red kangaroos is largely explained by the additional energy needed for growth.
Field metabolic rate and water turnover of red kangaroos and sheep in an arid rangeland: an empirically derived dry-sheep-equivalent for kangaroos
(Munn A. J., et al., 2008)
Sustainable management of pastures requires detailed knowledge of total grazing pressure, but this information is critically lacking in Australia’s rangelands where livestock co-occur with large herbivorous marsupials. This paper presents a comparative measure of the field metabolic rate of Australia’s largest marsupial, the red kangaroo with that of domestic sheep. This research tested the assumption that the grazing pressure of red kangaroos is equivalent to 0.7 sheep, and show this to be a two-fold overestimation of their contribution to total grazing. With lower water turnover, this research suggests that removing kangaroos may not markedly improve rangeland capacity for domestic stock, but rather that their use in consumptive and non-consumptive enterprises could provide additional benefits for Australia’s rangelands.
(Munn & Dawson, 2003)
Kangaroos at the YAF stage are making the transition from a milk-based diet to one of herbivory and an inability to adequately digest high-fibre feeds may contribute to their high mortalities during drought. This research examined the role of milk in the nutrition of red kangaroo YAFs fed forages of different fibre content and evaluated it as an extra energy and/or nitrogen source. The results indicated that when adequate high-quality forage is available, YYAF red kangaroos are not markedly dependent on milk and can sustain growth rates equivalent to those under ideal conditions. However, during drought when only poor-quality, low-nitrogen feed is available, YAF require substantial milk intakes.
(Wilson G. R., How kangaroos swim, 1974)
Underwater photos were taken of two male red kangaroos whilst swimming to understand the swimming action of kangaroos. The kangaroos were found to be excellent swimmers with forelimbs and hind limbs moving ipsilaterally, unlike on the land.
Hydrogen utilising bacteria from the forestomach of eastern grey (Macropus giganteus) and red (Macropus rufus) kangaroos
(Oewerkerk, Maguire, McMillen, & Klieve, 2009)
This research analyses gut contents from eastern grey and red kangaroos to better understand the forestomach fermentation processes of the kangaroos and the relationship with methane production.
(Dawson T. J., Kangaroos, 1977)
Overview of the species, a brief review of their evolution, reproduction, temperature regulation, digestion and the reason they hop. This paper paints a picture of a group of mammals that are not at all primitive but have adapted and radiated rapidly in response to new and changing environments.
Mechanistic explanations for drought-related mortality of juvenile red kangaroos; implications for population dynamics and modelling
(Munn & Dawson, 2010)
This work presents findings that investigates the causes for juvenile kangaroo mortality during drought and how kangaroos’ physiology interacts with their environment to affect survival and identifies the need for further research into the costs of locomotion on juvenile kangaroos and the short term impacts of water restriction.
The effect of drought on kangaroo populations (PDF only)
(Caughey, Grigg, & Smith, 1985)
Kangaroos declined by approximately 40% across more than a million square kilometres of inland eastern Australia during a drought between April 1982 and March 1983. The rate of decline showed no correlation with the density of kangaroos. The researchers suggest that such droughts and the consequent mortality and reduced fecundity are intrinsic to the ecology of kangaroos.
(Green-Barber & Old, 2018)
The genetic diversity of an eastern grey kangaroo (Macropus giganteus) population surrounded by landscape barriers was examined. DNA was extracted from tissue samples from 22 road-killed kangaroos, and blood samples from four live captured kangaroos. Amplified loci were used to determine relatedness between individual kangaroos. The level of relatedness and location of road-killed kangaroos were compared to evaluate spatial autocorrelation. The expected and observed heterozygosity confirmed the loci were polymorphic and highly informative for use in this population. One pair of kangaroos were identified to be full siblings, and a high proportion were identified as half siblings. Six positive parentage assignments were detected. No correlation between relatedness and crossing site was detected.
The ecophysiology of survival in juvenile red kangaroos Macropus Rufus: greater demands and higher costs
(Munn & Dawson, 2004)
YAF and weaned kangaroos have the highest drought-related mortalities of any cohort and show notable differences from adults in their basic physiology. YAF and weaned M. rufus, for example, had a resting metabolic rate (kJ kg-1 d-1) twice that of mature females and 1.5 times that expected for an adult marsupial of equivalent body mass (i.e., kJ kg-0.75 d-1). This greater energy turnover was largely explained by their metabolic demands for growth; juveniles required 70 – 95% of the digestible energy intake (kJ d-1) of mature, non-lactating females. Meeting these costs may not be a problem for juveniles when high-quality, low-fibre forage is available, but they were constrained when only hard-to-digest, high-fibre forage was available.
Unravelling methanogenesis in ruminants, horses and kangaroos: the links between gut anatomy, microbial biofilms and host immunity
Explores why macropods and horses produce less methane than ruminants when digesting the same feed. This review draws on microbiological studies of the mammalian gut as well as other microbial environments. Hypotheses are advanced to account for published findings relating to the gut anatomy of herbivores and humans, the kinetics of digesta in ruminants, macropods and equids, and also the composition of biofilm microbiota in the human gut as well as aquatic and other environments where the microbiota exist in biofilms.
Ventilation patterns in red kangaroos (Macropus rufus Desmarest): juveniles work harder than adults at thermal extremes, but extract more oxygen per breath at thermoneutrality
(Munn, Dawson, & Maloney, 2007)
Juvenile mortalities in large mammals are usually associated with environmental extremes, but the basis for this vulnerability is often unclear. Because of their high surface area to volume ratio, juveniles are expected to suffer greater thermal stresses relative to adults. Coping with thermal stress requires the ventilatory system to accommodate increases in oxygen demand and respiratory water loss at thermal extremes. Because juveniles are smaller than adults, these demands may set up different constraints on their ventilatory system. Using red kangaroos (Macropus rufus Desmarest), an arid zone species, we compared the ventilatory capabilities of juveniles and adults at thermoneutral (25 degrees C) and extreme (-5 degrees C and 45 degrees C) ambient temperatures. We used an allometry to compare juvenile to adult ventilation, using predicted body mass scaling exponents for oxygen consumption (0.75), respiration rate (-0.25), tidal volume (1.0), ventilation rate (0.75) and oxygen extraction (0.0). At ambient 25 degrees C, the juveniles’ resting metabolic rate was 1.6 times that of the mature females (ml min(-1) kg(-0.75)), accommodated by significantly higher levels of oxygen extraction of 21.4+/-1.8% versus 16.6+/-1.9% (P<0.05). At thermal extremes, juveniles showed typical mammalian responses in their ventilation, mirrored by that of adults, including higher metabolic and ventilation rates at ambient -5 degrees C and shallow panting at 45 degrees C. However, at thermal extremes the juvenile kangaroos needed to work harder than adults to maintain their body temperature, with higher rates of ventilation at ambient -5 degrees C and 45 degrees C, accomplished via larger breaths at -5 degrees C and higher respiratory rates at 45 degrees C.
(Dawson, Warburton, Richards, & Milne, 2015)
Pentapedal locomotion is the use of the tail as a fifth leg during the slow gait of kangaroos. Although previous studies have informally noted that some smaller species of macropodines do not engage in pentapedal locomotion, a systematic comparative analysis of tail use during slow gait across a wide range of species in this group has not been done. Analysis of relative movement of the pelvis, tail, and joint angles of the lower limbs during slow gait, using 2D landmark techniques on video recordings, was carried out on 16 species of Macropodinae. We also compared the relative lengthening of the tibia using crural index (CI) to test whether hindlimb morphology was associated with pentapedal locomotion. Pentapedal locomotion was characterised by three features: the presence of the ‘tail repositioning phase’, the constant height of the pelvis and the stationary placement of the distal tail on the ground during the hindlimb swing phase. The mean CI of pentapedal species was significantly greater than that of non-pentapedal species (1.71 versus 1.36; P < 0.001). This lends support to the hypothesis that the use of pentapedal locomotion is associated with the relative lengthening of the hindlimb, which in turn is associated with body size and habitat preference within the Macropodinae.
Water metabolism and renal function and structure in eastern grey kangaroos (Macropus giganteus): responses to water deprivation
(Blaney, Dawson, McCarron, Buffenstein, & Krockenberger, 2000)
The eastern grey kangaroo (M. giganteus) is usually found in mesic habitats but in the past 30–40 years it has expanded its range into arid rangelands. A suggested reason for this expansion has been the provision of additional water sites for domestic stock. In this study we examined aspects of kidney function and water metabolism of M. giganteus. This was done during normal hydration and water restriction so that the water-conserving abilities of M. giganteus could be compared with those of the red kangaroo (M. rufus), the habitat of which is arid rangelands and desert. The indices relative medullary thickness (RMT) and medullary to cortical ratio, derived from the morphology of the kidney, are indicators of renal concentrating ability. In M. giganteus both these indices were lower than in M. rufus: the RMT was 5.24 0.15 (mean s.e.) for M. giganteus and 6.00 0.10 for M. rufus. Measured maximal urine concentrations of these species were 2444 59 (M. giganteus) and 3135 165 mosmol kg–1 (M. rufus), with the respective maximum individual concentrations being 2752 and 4054 mosmol kg–1. Kidney function in hydrated and dehydrated M. giganteus was assessed via glomerular filtration rate, urine flow rate and concentration index. As measured by these parameters, M. giganteus had renal water-conserving capacities similar to, or superior to, those of many comparable-sized arid-zone-inhabiting placental mammals, but below those of M. rufus. Water metabolism, as measured by water turnover, showed a similar pattern.
Seasonal anoestrus in western grey kangaroos (Macropus fuliginosus ocydromus) in south-western Australia
(Mayberry, Maloney, Mawson, & Bencini, 2010)
Public opposition to culling has generated interest in wildlife management through fertility control. Temporary, non-invasive methods of fertility control, such as by xenobiotics, can be best employed with an understanding of the target species’ breeding cycle. We used head length to calculate the conception date of 136 pouch-young of western grey kangaroos (Macropus fuliginosus ocydromus) from four sites around Perth, Western Australia, between May 2006 and October 2008: Thomsons Lake Nature Reserve (n = 80), Harry Waring Marsupial Reserve (n = 11), Melville Glades Golf Club (n = 29), and Marangaroo Golf Course (n = 16). In total, 78% of all pouch-young were conceived in the months of December–February, 11% in November, 6% in March, and less than 2% in each of October, April and May. We examined the ovaries of 134 females culled from Thomsons Lake Nature Reserve during the months of May–July 2006. Only seven ovaries had a follicle of at least 5 mm and none had an active corpus luteum. These data indicate that the breeding activity M. f. ocydromus is restricted almost exclusively to the months of November–February. A practical application of this finding is that temporary fertility controls applied early in October will provide a full year of birth control if they remain active for seven months.
(Phillips, Haouchar, Pratt, Gibb, & Bunce, 2013)
The marsupial genus Macropus includes three subgenera, the familiar large grazing kangaroos and wallaroos of M. (Macropus) and M. (Osphranter), as well as the smaller mixed grazing/browsing wallabies of M. (Notamacropus). A recent study of five concatenated nuclear genes recommended subsuming the predominantly browsing Wallabia bicolor (swamp wallaby) into Macropus. To further examine this proposal we sequenced partial mitochondrial genomes for kangaroos and wallabies. These sequences strongly favour the morphological placement of W. bicolor as sister to Macropus, although place M. irma (black-gloved wallaby) within M. (Osphranter) rather than as expected, with M. (Notamacropus). Species tree estimation from separately analysed mitochondrial and nuclear genes favours retaining Macropus and Wallabia as separate genera.
(Deakin, Waters, & Marshall Graves, 2010)
Research into marsupial genetics and genomics informs many fields, as reflected by the content of this book, from animal breeding to genome sequencing projects, the development of bioinformatic tools and programs to deal with some of the unique features of marsupial genomes, to gene and genome evolution, the role of genes in reproduction and development, and of course population genetics and conservation. Often these areas overlap, and there is a high degree of collaboration between different groups working in this field, as is evident by the extent of crossreferencing between chapters. Through the compilation of work featured here, we hope this book will highlight more areas of potential collaboration and result in even more rapid progress in this field.
Thermoregulation by kangaroos from mesic and arid habitats: Influence of temperature on routes of heat loss in eastern grey kangaroos (Macropus giganteus) and red kangaroos (Macropus rufus)
(Dawson, Blayney, Munn, Krockenberger, & Maloney, 2000)
The researchers examined thermoregulation in red kangaroos (Macropus rufus) from deserts and in eastern grey kangaroos (Macropus giganteus) from mesic forests/woodlands. Desert kangaroos have complex evaporative heat loss mechanisms, but the relative importance of these mechanisms is unclear. Little is known of the abilities of grey kangaroos. Our detailed study of these kangaroos’ thermoregulatory responses at air temperatures (T-a) From -5 degrees to 45 degrees C showed that, while some differences occur, their abilities are fundamentally similar.