Kangaroos
 Aliases |
Feeding |
Reproduction |
| Appearance |
Hopping |
Social System |
| Behaviours |
Mortality |
Status |
| Distribution |
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| The sources of this information are provided under Resources | ||
Aliases |
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| Taxonomic classification | ||
| Superfamily | Macropodoidea | big footed 62 species in Australia & Papua New Guinea size 1 kg - 90 kg |
| Family | Macroprodinae | kangaroos and wallabies |
| Genus | Macropus | kangaroos six largest species of the family |
Relationships among Kangaroos
| Genus | Macropus Kangaroos share:
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| Species | rufus | fuliginosus | giganteus | antilopinus | robustus | bernadus |
| Common Names | Red Kangaroo, Marloo. Blue-flier (female) |
Western Grey, black-faced kangaroo, sooty kangaroo, mallee kangaroo, stinker | Eastern Grey, forester, scrubber, Great Grey | Antilopine Kangaroo | Common Wallaroo, Euro, briggada | Black Wallaroo |
| Grouping | Red Kangaroo | Grey Kangaroos | Antilopine Kangaroo | Wallaroo / Euro |
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Appearance |
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| Species | males | females | ||
| Height* | Weigh | Height* | Weight | |
| Red Kangaroo | 1.8 m | 90 kg | 1.25 m | 35 kg |
| Grey Kangaroos | 1.6 m | 70 kg | 1.2 m | 35 kg |
| Antilopine Kangaroo | 1.5 m | 49 kg | 1.0 m | 20 kg |
| Euro | 1.6 m | 58 kg | 1.2 m | 25 kg |
| Black Wallaroo | 1.0 m | 22 kg | 0.8 m | 13 kg |
| * Height is measured when sitting up on their haunches. | ||||
| Red Kangaroo | black and white patch at side of muzzle; the tip of the nose is naked and sharply outlined |
| Grey Kangaroos | muzzle covered by fine hair; only the margins of the nostrils are bare black skin |
| Euro - Wallaroo | nose is completely naked |
Behaviours |
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Social interaction |
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these are actions that promote the unity of a group; don't include either displays of aggression or reproductive behaviour |
Between group members: |
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mutual nose touching and sniffing, touching the lips of another, other touching and sniffing, grooming others, nuzzling a female's pouch |
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submissive behaviour - one animal, often smaller, holds its body close to the ground and its head may quiver |
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play-fighting among young, subadults, or mother and young - two animals involved grasp each other around the neck, touching forepaws and kicking |
Mother and offspring: |
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mother grooms a young at foot while it is suckling or just after |
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young nuzzles its mother's pouch either to get in or to suckle or for reassurance the young may put its head into the pouch for a few seconds |
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young licks its mother's lips for several minutes, apparently collecting saliva; it is thought that this may result in the passage from mother to young of the digestive micro-organisms required for the fermentation of vegetation for nutrition |
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play-fighting |
Aggression |
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fights ('boxing') between large males are rare |
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most fights are one-sided and end quickly; the challenged individual usually moves away |
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a submissive 'cough'/cluck is heard in eastern greys, wallaroos, euros but not in reds |
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threat displays indicate an intention to act aggressively; these include upright posture, stiff-legged walking, pulling on grass or bushes |
Distribution |
| Between them, the kangaroos range over most of Australia. |
| In some areas there may be only one species while in other places several species occur. |
| Species | Habitat preference |
| Red Kangaroo |
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| Western Grey Kangaroo |
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| Eastern Grey Kangaroo |
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| Antilopine Kangaroo |
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| Euro group (4 subspp) |
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| Black Wallaroo |
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Feeding |
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reds and greys may feed in large mobs - size depends on the quality of food |
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most active at dawn and dusk; relatively inactive in middle of both day and night |
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time spent grazing varies seasonally between 7 and 14 hours |
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rest during the day in the shade of woodland; move onto grasslands to feed |
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eat a variety of plants but mainly grasses |
Hopping |
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kangaroos are unique in being the only large animals that use hopping for locomotion |
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they walk at slow speeds and start hopping as speed increases |
Energetics of hopping |
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when hopping starts its costs are high |
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as speed increases, the energy costs change little which means that a kangaroo hopping at a moderate speed (>15 km/hr) uses less energy than a similarly-sized animal that is running |
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for red kangaroos, the most comfortable speed is 20-25 km/hr |
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as speed increases up to about 40 km/hr, the hopping rate remains constant but the length of the hop increases |
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although red kangaroos can hop at speed of 65-70 km/hr for short distances, at these speeds the hopping rate increases as well as the hop length |
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while hopping has benefits in energy expenditure at high speed, at low speeds (below 6 km/hr) they have an awkward walk using their hind legs with the tail providing additional support for the front legs, and this is both clumsy and energetically expensive |
Lack of Nutrition |
particularly in young animals that don't have body reserves |
| Predation | dingoes, eagles, foxes, humans |
| Disease | filarioid nematode worm, Pelecitus roemeri found in the connective tissue; lumpy jaw caused by bacterium Fusobacterium necrophorum * |
| Environmental stress | drought, flooding, severe wet and cold weather |
| * the incidence of mortality by disease vectors usually involves the interrelationship of some of the other factors listed | |
General |
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reds, euros, wallaroos - breed continuously under good conditions; greys are usually seasonal breeders |
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marsupial reproduction depends on lactation to nourish the poorly developed young; consequently, female marsupials have a greater investment in the care of their young |
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females coming into oestrus extend their area of activity to attract the largest male in that area; so, a large male will be able to mate with more females |
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there are indications that a female (of some species) may invest less in male offspring in years when conditions are poor and that this explains the increased male mortality of young males; the reasoning behind this is that to be a successful breeder a male needs to be large and males raised in poor seasons will never become the dominant male, whereas a female produced during a poor season will still breed and pass on her mother's genes |
Gestation and birth |
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kangaroos have a relatively long gestation period compared to other marsupials ranging from about 31-36 days |
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exhibit embryonic diapause - a viable embryo is carried in the uterus with its development arrested at an early stage (except the Western Grey); development is recommenced after final pouch exit by the previous young |
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mother assists the newly-born into the pouch through pouch cleaning and birth posture (characteristic for each species); in reds, the female brings her tail forward between her hind legs and leans back against a tree while antilopines don't require back support and greys don't bring the tail forward; the newborn are visible for about three minutes before disappearing into the pouch |
Lactation |
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in the euro, wallaroos, and red the young is continuously attached to the nipple until 120-130 days |
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composition of the milk is tailored to the requirements of the developing young e.g. around the time of hair formation, there is an increase in sulphur-containing amino acids (hair has a high content of sulphur-containing proteins) |
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facilitates the transfer of immunity to the newborn that is now in an unsterile pouch; around birth the mammary glands secrete a clear fluid that has free-floating cells and maternal immunoglobulins (similar to the colostrum of placental mammals) |
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mother can simultaneously produce milk of two different compositions for the joey that has emerged from the pouch but is not weaned and for the newborn |
Emergence from the pouch |
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young first emerges from the pouch usually by falling out; this occurs after 185 days in reds, up to 298 days for western greys |
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mother's muscles control pouch size and opening; when she is alarmed, the pouch is pulled tight against her body so that the joey cannot emerge; she can relax the pouch and let the joey fall out; she can also contract the pouch and tip the joey out |
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joeys entering the pouch complete a somersault and end up facing the pouch opening |
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even after permanent emergency, the joey will continue to suckle on its usual teat for some months |
| Species | Male | Female |
| Red | 24 | 15-20 |
| Western Grey | 31 | 14 |
| Eastern Grey | 48 | 18 |
| Euro | 24 | 21 |
Social system |
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generally sedentary, home range (the area covered by an individual in the normal activities of feeding, mating, and caring for young) of a few kilometres across; home ranges are not defended |
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show fidelity to the home range, often returning after being forced away to find food in other places during drought |
| Aggregation | grouping of individuals at a resource (food, water, shade); individuals are not necessarily interacting |
| Mob | a set of individuals whose home ranges overlap; commonly interact with each other; young animals and a lesser number of adults may disperse to different mobs; sufficient interaction to establish dominance hierarchies in relation to feed and shade for resting |
| Group | social neighbourhood of an individual; members of a group communicate and interact as a unit; consist of less than 6 individuals; mainly females and their offspring, particularly daughters |
| Species | Typical group size* | Aggregation size | Home range size** |
| Red | 3 - 4 | 20 | 150 ha |
| Western Grey | 2 - 16 | 100 ha | |
| Eastern Grey | 3 - 23 | 80 | 20 ha |
| Eastern Grey (Tasmania) | 5 | ||
| Antilopine | 3 - 12 | 50 | female14 ha male 76 ha |
| Euro | 2 - 3 | 10-37 ha | |
| * (from Dawson TJ, 1995, p29) ** depends on sex, season, habitat, time span |
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Status |
| None of the kangaroos are endangered, although locally populations may be limited. |
References - books
- Kangaroos - Biology of the Largest Marsupials, TJ Dawson, 1995. University of New South Wales Press Ltd, Sydney.
- Encyclopedia of Australian Wildlife, Reader’s Digest Australia Pty Ltd, 1997. Reader’s Digest (Australia) Pty Ltd, Surrey Hills.
- Complete Book Of Australian Mammals, R Strahan (ed), 1983. Angus & Robertson Publishers, London.