Greater Bilby

Greater bilbies used to be found (>70%) throughout continental Australia, with populations in South Australia, Western Australia, the Northern Territory, and New South Wales. In southwestern Queensland, there were also small populations. The home range of Macrotis lagotis was drastically decreased when Europeans introduced feral cats (Felis silvestris), red foxes (Vulpes vulpes), and rabbits (Oryctolagus cuniculus). Bilbies are now restricted to about 20 to 30 percent of their historical range. The Great Sandy, Tanami, and Gibson deserts of northwest Australia, as well as the southwest tip of Queensland, are home to Macrotis lagotis. In South Australia, greater bilbies are now presumed extinct. Due to the installation of predator-proof enclosures and intensive monitoring of reintroduced populations, reintroduction operations have begun in southern South Australia, southwestern Queensland, western New South Wales, and regions of Western Australia, with some success.


Habitat

Greater bilbies live in dry, hot environments such as deserts, dunes, and grasslands. There are three basic types of vegetation that are typically seen in a bilby environment. Tussock grassland, which may be found on hills and uplands, mulga woodlands and shrublands, and hummock grassland, which can be found on dunes and sandy plains, are all examples. Greater bilbies are fossorial, meaning they live in rocky or clayey regions.


Physical Description

Greater bilbies have huge, hairless ears that resemble rabbit ears, as well as long pointed snouts having sensory vibrissae and a hairless pink nose. Their fur is silky, soft, and bluish-grey in appearance, with a fawn mix over the bulk of their bodies. The fur on the belly is white or cream. The first 40 percent of the tail is the same blue-grey as the body, with the rest black and the final 40 percent pure white. Females' pouches open to the back to prevent soil from filling them up during burrowing. Three clawed digits and two clawless digits make up the strong forelimbs. The hind limbs of greater bilbies are thin and resemble those of kangaroos. Bilbies gallop around the desert with their legs rather than hopping. Termites are easy to catch because their tongues are long, sticky, and slender. Males and females are sexually dimorphic, with males having double the body mass as females (800 to 2500 g for males relative to 600 to 1100 g for females). Males have larger foreheads and longer canines in addition to being larger.


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Reproduction

They have a polygynous mating system. The most dominant male will mate with the most dominant female and additional females, whereas lower males will mate with females that are equal to or below them in the social order. Males approach and follow females for reproduction. 

Greater bilbies can breed at any time of year, but whether or not they do so is dependent on the circumstances. Females in dry regions may delay reproducing until conditions are suitable for supporting the nutritional demands of nursing and the young's independence. When the habitat is right, a female bilby can have up to four litters each year, each with one to two offspring, though up to four offspring have been observed. Greater bilbies attain sexual maturity at roughly 5 months (or 560 g), whereas males need roughly 8 months (or 800 g) to attain sexual maturity. The oestrus cycle in women lasts about 21 days. The gestation period of greater bilbies is one of the shortest of all mammals, at only 14 days. The tiny, premature child climbs inside its mother's pouch after fertilisation, attaches itself to a nipple, and stays there for 75 days. For an additional 14 days, the mother looks after the children. The young will thereafter be released from their mother's burrow and left to fend for themselves.

Females are the only ones who look after the children. Young greater bilbies climb into their mother's pouch after a brief gestation period, where they spend the majority of their time with her. During the 75 days that the young bilbies are in the pouch, the babies continue to grow at a rapid rate, reaching a weight of 200 g by the time they depart. The children get all of their nutrition from their mother's milk when they're in the pouch. Female bilbies have nipples that hang outside the pouch and nipples that are deep inside the pouch. For kids living outside the pouch vs within the pouch, each type of nipple produces a distinct sort of milk. 

The young do not return to their mother's pouch once they have emerged. Frequently, the female has already mated, and a fresh litter enters the pouch shortly after the last one has gone. The mother hides these tiny juveniles in one of her burrows, where she will return every two weeks to allow her kids to feed. The young exit the burrow after two weeks and are left to fend for themselves with no more parental care. Only around a quarter of the offspring produced will reach adulthood, with the rest becoming food for predators or succumbing to the weather.


Lifespan/Longevity

Although the usual maximum lifespan in captivity is 6 to 7 years, the oldest larger bilby in captivity lived for around 10 years. The wild longevity of bigger bilbies is unknown.


Behaviour

Greater bilbies are mostly solitary creatures, though some may live in pairs (usually two females). Greater bilbies are semi-fossorial animals that dig slightly swirling burrows up to 3 metres long and 2 metres deep. Multiple exits are possible in these tunnels, which is especially crucial if the burrow is invaded by a predator. A single bilby can have many burrows scattered over its territory. Predators, as well as the harsh sun and other environmental factors, are all protected by these burrows. They also serve as a haven for the young while the parents forage. Greater bilbies emerge from their burrows when the sun sets to feed and look for mating possibilities. 

Greater bilbies may return to their burrow to relax or if they are threatened by a predator at any time during the night. Males, females, and young home ranges are likely to overlap, although social contact is minimal outside of mating. Male bigger bilbies in captivity, on the other hand, appear to have a clear social structure. This hierarchy is not maintained by high amounts of aggression, as it is with bandicoots. Outside of burrows, scent markings appear to indicate where an animal is in the dominant order.


Communication

Greater bilbies have weak eyesight and rely on hearing and smell to navigate their surroundings. They have a keen sense of smell, which they utilise to detect food buried underground as well as other people's scent markings. Greater bilbies use their large ears to listen for insects underneath as well as predators. Hearing, on the other hand, appears to be far less significant than olfaction. Greater bilbies' ears are also utilised to control body temperature. Scent marks are the most common way for males to communicate. Males leave their urogenital region rubbed around the burrow opening to indicate the outside of their burrows. 

Males may also leave their mark on burrows where they have mated with females. Scent marking appears to be linked to dominance; dominant males mark over regions previously marked by less dominant males. Less dominant males also avoid entering dominant males' burrows. Females do not scent mark their areas very often. Because males are rarely, if ever, aggressive towards females, scent markings by males have little influence on females.


Food Habits

Greater bilby does not drink water; instead, it gets their water from the food they eat. Seeds, especially those of the grasses Dactyloctenium radulans and Yakirra australiense, bulbs, larvae, termites, ants, spiders, fruit, fungus, lizards, and occasionally eggs, snails, or small mammals, make up their opportunistic diet. The ratio of insect to plant matter in their diet varies according to the area and season. Greater bilbies have superb hearing in addition to a sharp sense of smell. Greater bilbies can hear termites and other insects digging underground by pressing their large ears against the earth. They then dig up insects, bulbs, and other buried food using their keen claws and muscular forelimbs. Greater bilbies dig tunnels leading to termite chambers and lap them up with their long, slender tongues since their soft fur does not protect them well from termite bites. Unfortunately, this feeding strategy consumes a significant amount of soil and sand. Greater bilbies benefit from controlled burns because they encourage the growth and seed development of their favourite feeding plants.


Predation

While natural species such as carpet pythons (Morelia spilota), monitor lizards (Varanidae), and some raptors (Accipitridae) can attack greater bilbies, these species are the most common and devastating predators. Dingoes, red foxes, and feral cats are non-native species that hunt on bigger bilbies. In 1855, European settlers brought red foxes to Australia for the purpose of leisure hunting. Red foxes swept across continental Australia within 100 years of their arrival, and they now live in every region except the tropical northern part of the continent. Domestic cats were first distributed over Australia in 1855 to control the populations of European rabbits, mice, and rats, as well as other unwanted species. Domestic cats soon spread across Australia's whole continent, eradicating many native species.


Ecosystem Roles

While they provide food for a variety of predators, both native and foreign, Macrotis lagotis' most significant job is that of an "ecosystem engineer." “Organisms that modify, maintain, generate, or destroy structure within the physical environment” are ecosystem engineers (Eldridge and James, 2007). Foraging for bulbs, seeds, and insects, bigger bilbies dig pits up to 25 cm deep, which are then abandoned. Seeds, water, and other organic materials settle in these pits, where they begin to decay. In the Australian desert, greater bilby pits become "fertile patches," where some seeds give additional nourishment to help them germinate in an otherwise hostile environment. Environments without bigger bilbies and a related, native fossorial group, bettongs (Bettongia), were compared to those with these two native species. Despite the presence of rabbits, which also dig burrows, it was concluded that habitats without these native fossorial animals experienced devastating losses of native Australian wildlife.


Economic Importance for Humans

Greater bilbies were previously a popular traditional food and fur source for Australia's Aboriginal people. Due to the rarity of greater bilbies and their protected status, this practice has all but disappeared. The Commonwealth of Australia Endangered Species Program uses greater bilbies as a mascot. They're also displacing rabbits as the Easter icon in Australia, with chocolate bilbies being offered instead of bunnies.


Conservation Status

Bilby numbers have been declining since the 1800s due to habitat loss due to land-use alteration, as well as increased predation and competition due to species invasions. The International Union for Conservation of Nature (IUCN) listed the bilby as an endangered species on its Red List of Threatened Species between 1982 and 1994. The animal's status has been raised to vulnerable by the IUCN since 1994. Although bilby reintroduction initiatives have been developed in New South Wales and Southern Australia, as well as some sections of Western Australia and Queensland, it is estimated that less than 10,000 bilbies survive in the wild.

The greater bilby and the European rabbit (Oryctolagus cuniculus), an invasive species which has become a plague in Australia's agricultural industry, are known to compete for food. In 1991, members of the Foundation for Rabbit-Free Australia Inc. launched a campaign in Australia to replace the "Easter bunny" with the "Easter bilby" in order to boost public awareness of bilby conservation while still educating Australians about the ecological devastation caused by introduced rabbits.


Facts

  • The greater bilby is known as urgata in the local indigenous language.

  • The rabbit-eared bandicoot is another name for them.

  • In Australia, rather than the Easter bunny, the Easter bilby is widely celebrated, and chocolate bilbies are widely available.

  • Greater bilbies are one of two kinds of bilbies that once lived in Australia. The lesser bilby, on the other hand, became extinct in the 1930s.

  • They are the largest bandicoot species in Australia


Conclusion

Bilby (Macrotis lagotis), also known as the greater bilby, dalgyte, or greater rabbit-eared bandicoot, is a little, burrowing, nocturnal, long-eared marsupial that is native to Australia and belongs to the Thylacomyidae family. Bilbies occupied habitats spanning more than 70% of Australia prior to the advent of Europeans. They are currently only found in the Great Sandy, Tanami, and Gibson deserts of northwestern Australia, as well as a tiny area in southwestern Queensland. Bilbies are closely related to bandicoots, which belong to the Peramelidae family. The bilby has a long nose, blue-grey fur, a white underbelly, and long, hairless ears that look like rabbit ears. 

A prominent band of black hair runs down its tail, terminating in a white tuft that surrounds a bare, spurlike tip. Males are roughly twice as large as females in this species, with the greatest males reaching 55 cm (about 22 inches) in length and weighing 2.5 kg (about 5.5 pounds). The forelimbs' ends are made up of five digits, the middle three of which have claws. Bilbies have hind limbs that are similar to those of kangaroos, but instead of hopping, they lope like hares.

FAQs (Frequently Asked Questions)

1. How Many Bilbies are Left?

Ans: Because Bilbies are exclusively found in Australia, it is estimated that there aren't many left in the globe. There are roughly 600-700 bilbies left in the world, according to estimations.

2. Where Can We Find Greater Bilby?

Ans:  Greater Bilby is a generalist animal that used to be present in 70% of Australia. The Tanami Desert in the Northern Territory, the Gibson, Little, and Great Sandy Deserts, the Pilbara and Kimberley regions of Western Australia, and the Mitchell Grasslands in southwest Queensland are now home to about 15% of the population.

3. What are Threats to Greater Bilby?

Ans: Bilby populations dropped dramatically in the early twentieth century, and 10% of that reduction occurred in the last 12 years, with the present population believed to be fewer than 1,000. Competition for food from cattle and introduced species like rabbits, as well as predation by foxes and feral cats, are the two main dangers. Bilbies are known for enclosing themselves in their tunnels to protect themselves from predators who may often try to follow them in. Bilbies have been impacted by changing fire patterns. That's why it's critical to carry out conventional patch burning in regions where Bilbies still exist.