Australia, officially known as the Commonwealth of Australia, is an island nation in Oceania. It consists of the island of Australia, the island state of Tasmania, as well as over 8,000 smaller islands. Australia is the smallest continent, and is often referred to as the world's largest island. It is the sixth-largest country in the world by size. The Commonwealth of Australia was formed in 1901 by the merging of the six colonies of Queensland, Victoria, New South Wales, South Australia, Western Australia, and Tasmania. King Edward VII officially granted the Commonwealth of Australia it's own Coat of Arms in 1908.
First Coat of Arms
The Commonwealth Coat of Arms, granted in 1908, featured a shield of blue and white with six smaller shields along the border, and the the cross of St George at the center. The shield was held by a kangaroo on the left and an emu on the right standing on a grassy mound. Above the shield was a seven-pointed star and below the shield were the words "Advance Australia" on a banner.
Second Coat of Arms
In 1912, King George V granted the Commonwealth of Australia a second Coat of Arms. The new coat of arms replaced the grassy mound with a backing of golden wattle (Acacia pycnantha), Australia's national flower. St George's cross was replaced by symbols of the six states of Australia. The banner beneath the shield was changed to say only "Australia."
Significance of the Animals on the Coat of Arms
Because of their inclusion on the Commonwealth Coat of Arms, the red kangaroo (Macropus rufus) and the emu (Dromaius novaehollandiae) have become known as Australian symbols.
The red kangaroo is one of the most popular and well-known native Australian animals. It is the largest terrestrial mammal endemic to Australia and is found all across the mainland. Their total population is now nearly 50 million, almost double the human population of Australia. Given the harsh weather of the Australian continent, many animals cannot live across vast swathes of the continent in much the same way that the red kangaroo has been able to. This has placed the red kangaroo in the ICUN conservation category of "least concern." Red kangaroos have front limbs with small claws and two muscular and robust hind-limbs that are mainly used for jumping. They also have a strong tail which is used for support when standing in an upright position and balance while leaping. In a typical leap, the male kangaroo can cover 8-9m while reaching heights of 1.8-3m, though the average is 1.2-1.9m. A prevailing theory is that kangaroos cannot easily walk backward, moving only forwards.
The emu is another animal endemic to Australia. It is the second tallest bird in the world and the largest native bird in Australia. The flightless bird is found throughout most of the Australian continent. Their stable population and wide range has placed them in the the ICUN conservation category of "least concern" alongside the kangaroo. The emu is an important animal in Australian Aboriginal mythology, included in creation myths and cultural dances. Although flightless, emus have specialized musculature to enable them to run very quickly. They also use their large wings to stabilize themselves while running. The average step is 3.3 ft while walking, but can reach 9 ft at a gallop, reaching almost 50km/h in speed and covering large distances.
It is widely thought that the two animals were chosen because of their difficulty in moving backwards. This would match the idea of the words "Advance Australia" included on the banner of the first coat of arms. The two animals then would represent Australia's attempts at progression, moving only forwards and never backwards. This idea is widely debated, however, with claims that both animals can move backwards, just not easily.
Another possible explanation is that both animals were chosen due to their popularity and size. It is suggested that kangaroos have at some points actually outnumbered humans populations in Australia. They are widely seen within the country, and a popular symbol of Australia to the rest of the world. In regards to size, the average high of the red kangaroo when standing upright is approximately 1.5 m (4.9 ft) tall. The high of the emu ranges between 4.9 ft to 6.2 ft. When placed on either side of the shield, the depictions of the red kangaroo and emu would be of similar heights.