Eastern Grey Kangaroo

Evolution

All Subspecies: -Macropus giganteus giganteus – found in eastern and central Queensland, Victoria, New South Wales and southeastern South Australia

Macropus giganteus tasmaniensis – (commonly known as the Forester Kangaroo) endemic to Tasmania

Existence: -About 15 million years ago, kangaroos started to appear. Their ancestors were opossum-like creatures that lived in the trees. Many types of species died out over time, but today, around 250 species of marsupial live in Australia.

Relatives: The kangaroo's closest relatives are wallabies and wallaroos, which are essentially smaller versions of kangaroos.

Ancestors: Kangaroos, wallabies, pademelons and tree kangaroos make up one family, while rat-kangaroos, bettongs and potoroosmake up the other.

Kangaroo Taxonomy

Kingdom

Animalia – Animal, animaux, animals

Phylum

Chordata – cordés, cordado, chordates

Class

Mammalia Linnaeus, 1758 – mammifères, mamífero, mammals

Family

Macropodidae Gray, 1821 – kangaroos, wallabies

Order

Diprotodontia Owen, 1866

Genus

Macropus Shaw, 1790

Species

Macropus giganteus Shaw, 1790 – Eastern Grey Kangaroo

Description:

All Eastern Grey Kangaroos have short hair, powerful hind legs, small forelimbs, big feet and a long tail. They have excellent hearing and keen eyesight. Their fur coat is grey and soft. Their muscular tail is used for balance when hopping, and as another limb when moving about.

-Eastern Grey Kangaroos can live for up to 18 years in the wild.

Large strong tails that they can balance on, and grey soft fur.

Habitat:

-Eastern gray kangaroos roam the forests of Australia and Tasmania and prefer to live among the trees, though they do take to open grasslands for grazing.

-They live in areas with more than 250 mm (10 in) of average annual rainfall.

-They are found in a variety of habitats, from semi-arid mallee scrub through woodlands to forested areas.

(Mallee are eucalyptus shrubs which grow in dry areas with poor soil.)

-A group of Kangaroos (called a mob) is usually made up of one dominant male, several adult females, and both male and female juveniles. Several mobs may graze together, in aggregations of up to 100 animals.

-Mobs of kangaroos travel long distances and easily get past artificial barriers such as stock fences.

-Temperatures run from 25°C (77°F) to 33°C (91°F). The dry season runs from May until October, and is characterized by warm, dry, sunny days and cool nights.

Diet:

-The Eastern Grey Kangaroo is predominantly a grazing animal with specific food preferences. They are herbivorous, favouring grasses but will eat a range of plants, including in some cases, fungi. With the grasses they prefer to eat young green shoots high in protein. Dry grass is difficult for them to digest.

-Spend about 6-10 hours a day eating/feeding.

Least Concern (Population Stable)

Social Structure:

-Eastern grey kangaroos are polygynous animals. Adult males take part in ritualized fights with rivals, and the dominant male being the most likely the only one to mate with the available females. Breeding continues throughout the year, peaking in summer. The young is born following a gestation period of 36 days.

-The species often live in large groups known as mobs. These mobs can range in numbers anywhere from small groups to more than hundred kangaroos. The kangaroo is a highly social species, and often engages in nose touching or sniffing to build cohesion within the group.

Reproduction:

-Eastern grey kangaroos are obligate breeders in that they can only reproduce in one kind of habitat. The female eastern grey kangaroo is usually permanently pregnant except on the day she gives birth; however, she has the ability to freeze the development of an embryo until the previous joey is able to leave the pouch.

-Kangaroo mating can be quite brief, or can last for 10 minutes or more with pauses. The female kangaroo often tries to get away after a minute or two, and he usually tries to hold onto her. Large male kangaroos have massive arms, which could help them hold onto females.

-The dominant male leads the mob and has exclusive access to the females for mating. A baby kangaroo is born only after about a month-long gestation period. Like all marsupials, the female kangaroo has a pouch, called a marsupium.

Development:

-The young joey is weaned at about 18 months of age. Even when the mother no longer allows it to suckle, it often remains in close association with her until it reaches sexual maturity. Eastern Grey Kangaroos can live for up to 18 years in the wild.

Causes of death:

-The lack of nutrition is, by far, the major reason why kangaroos die. The lack of nutrition is often caused by tooth wear and external factors such as extreme drought.

-Young kangaroos have a lack of reserves

-Predation by humans and animals affect kangaroos, wallabies, wallaroos, and quokkas. Grey kangaroos, on the other hand, prefer moving in covered areas and undergrowth of scrub.

-Wedge-tailed eagles, dingoes, and foxes are the natural predators of kangaroos. Humans also affect the kangaroo population due to commercial harvesting, roadkill, and habitat loss due to extensive farming and clearing of woodland.

Competition:

-The estimated competition coefficients indicate that bare-nosed wombats are a slightly superior competitor of eastern grey kangaroos than vice versa, and that intraspecific competition is almost twice as strong as interspecific competition.

IUCN:

-Least Concern (IUCN 3.1)

-According to the Australian Government Department of the Environment, the total number of the Eastern grey kangaroo is 16,057,783 individuals. Currently this species' numbers are stable and it is classified as least concern (LC) on the IUCN Red List.

Impact of humans:

-Large areas of land are still being cleared for housing and shopping centres, farming, mining and timber logging. Every time land is cleared, the kangaroos and wallabies and smaller macropods are forced to move to a different area where food and water may not be available or they are killed.

-The most common threats to Kangaroos are due to human activities, including hunting, and conflict with vehicles.