The 2019/2020 Australian bushfires caused the burning of 10 million hectares of natural habitat, affecting 1.25 billion animals. An estimated 30% of the koala population worldwide has been affected, placing the species at a new level of threat (Gonzalez-Astudillo et al., 2019; World Wide Fund for Nature, 2020). Although forest fires have recently become a serious threat to the species, the Koala population has been decreasing since the 18th century, when Europeans settled in Australia. This population decline can be partially attributed to several introduced threats that the population is not anatomically equipped to deal with. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Because of their diet, Koalas are arboreal animals, meaning that much of their locomotion consists of climbing and moving between tree branches. The functional anatomy associated with climbing in the Koala is best described when compared to its closest terrestrial relative: the Wombat. Koala and Wombat are both marsupials (Louys et al., 2009) and have many similarities including molecular data, dentition, posteriorly directed pouch and a rudimentary tail which highlight their close relationship (Grand and Barboza, 2001). However, due to their environment and diet - eucalyptus trees and leaves for Koalas, burrows and grass for Wombats - they have many derived traits. Koalas' sedentary position when climbing and feeding has resulted in their soles and palms facing medially allowing them to grasp the ground. trunk or branches of trees, while the Wombat has palms and plantigrade plants that allow stability and distribution of pressure during the load (Fig.1)(Young, 1881). Supination of the forelimbs of the Koala is facilitated by the deeply arched radius while the compact radius of the Wombat limits supination (Fig. 2) (Grand and Barboza, 2001). While this skeletal orientation aids climbing, it hinders Koalas' ability to travel between habitats in search of quality food sources and mates - however terrestrial locomotion is becoming increasingly important as human interference results in a habitat of increasingly fragmented eucalyptus (Grand and Barboza, 2001; Narayan and Williams, 2016). Compared to Wombats, Koalas also have an elongated humerus and a reduced olecranon (Fig. 2), this allows them to fully extend their forelimbs, increasing stride length (Grand and Barboza, 2001). Increased stride length is common in tree species and is hypothesized to reduce destabilizing peak forces when traversing narrow branches. This morphology further prevents excessive terrestrial locomotion as the slender humerus is not designed to support weight on solid surfaces with greater resistance. The lack of a notable olecranon also reduces stability against hyperextension of the elbow joint during loading (Gaschk, Frère, & Clemente, 2019). In addition to medial rotation of the limbs, Koalas also have an opposable big toe on each foot and two opposable digits on each hand to give them greater grip strength. All of their fingers are equipped with large, curved claws that allow them to further fix their position on a tree and cling to the bark (Young, 1882; Grand and Barboza, 2001; Gaschk, Frère, and Clemente, 2019). However, these also hinder land movement as they force the hands and feet to be spread apart and the fingers to be hyperextended when in contact with the ground, resulting in significant lateral displacement when the limbs are swung forward;this is very inefficient when considering speed versus energy consumption (Grand & Barboza, 2001; Shipley, Forbey, & Moore, 2009). These claws reduce the speed of terrestrial locomotion as they increase the stance phase required due to an increased reliance on precise finger placement to correctly apply pressure for propulsion (Gaschk, Frère, & Clemente, 2019). Similar to the forelimbs, the adaptations in the hindlimb musculature are also reversed. The lack of an iliac attachment for the external gluteus, the absence of the soleus, and a single origin of the biceps femoris together with the occasional attachment of the gracilis to the marsupial bone encourage medial rotation of the hindlimb (Young, 1882). These muscular dispositions also result in reduced mobility of the hip joint which contributes significantly to the biomechanical inefficiency of ground movement (Grand and Barboza, 2001). Due to their slow land speed and antisocial behavior, most koalas travel rather as individuals than in packs - Koalas are particularly vulnerable on land as they are exposed to road deaths and predator attacks, particularly by dogs ( Lassau et al., 2008; However, recent climate changes and developments in human settlements mean that eucalypt habitat is becoming increasingly fragmented (Narayan and Williams, 2016). Therefore, the Koala is forced to spend long periods of time moving on land between suitable habitats in search of food, water and mates (Gaschk, Frère, & Clemente, 2019). Because koalas have very few natural predators, they lack the adaptations needed to escape or defend themselves when threatened. Around peri-urban areas, wildlife habitats have been replaced with an area of ​​intense human activity full of threats in which Koalas are unable to thrive. Aside from their anatomical adaptations to the arboreal lifestyle, the other major components of Koala anatomy that place them at a significant disadvantage in today's environment are the adaptations that have arisen as a result of their diet. As a gut fermenter, the Koala is one of the few species capable of digesting the highly fibrous eucalyptus leaf and extracting limited nutrition and energy from the source. To allow the Koala to extract maximum nutrition, the species has an enormous caecum relative to its body size (Grand & Barboza, 2001; Shipley, Forbey, & Moore, 2009). Koalas are considered one of the most highly specialized folivorous mammals (Shipley, Forbey, & Moore, 2009). With over 93% of their diet composed of 120 tree species of the Eucalyptus genus, they are the most obligate consumers of eucalyptus (Grand and Barboza, 2001). It is hypothesized that Koalas have adapted to eating the eucalyptus leaf due to the lack of competition for the food source as it is highly toxic to many other species (Moore and Foley, 2000). Koalas' eucalyptus-based diet is notoriously low in energy and difficult to digest. With a diet high in indigestible waxes, toxic terpenoids and mass fiber, but low in calories, the Koala requires 19-22 hours a day of eating and sleeping just to meet basal energy needs and fund an average of 4 minutes a day of active movement ( Grand and Barboza, 2001 ; Johnson et al., 2018 ). They are unable to save energy for excessive movement or socializing, leading them to lead a sedentary and antisocial lifestyle. The low energy available to Koalas means that they require a basal metabolism significantly lower than the average of other mammals of similar size (Grand and Barboza, 2001). This led them to be conservationistsmetabolic in all possible ways. To minimize the energy spent regulating body temperature, koalas have highly insulating skin that keeps them warm in the windy treetop environment (Degabriele and Dawson, 1979). . When trying to keep cool, Koalas rely on the shade provided by the eucalyptus canopy and an area of ​​thin skin over the breastbone that press against cool areas of soil or bark to reduce body temperature (Smith, 1979) . However, although they reduce basic energy costs, their highly insulating skin led to the species being exploited by the fur trade in the 19th and 20th centuries, resulting in millions of casualties (Johnson et al., 2018). In addition to this, as climate change intensifies, causing more extreme weather, and their habitat continues to fragment, it is unlikely that the species will be able to maintain a healthy body temperature using these methods alone. The increasingly elusive nature of shade and cool surfaces poses a particular threat; high temperatures and limited water availability can lead to the death of many koalas due to dehydration or overheating. 91% of the energy that can be used from eucalyptus by koalas comes from digestion of cell contents rather than from the cell wall (Lanyon and Sanson, 1986), so it is important that the cellulose walls are broken down as much as possible to expose the maximum amount of content. This is done during chewing in Koalas, the grinding motion of the jaw breaks down the cell walls and maximizes the surface area to aid fermentation later. Because such importance is placed on the exposure of cellular contents, the species' dentition has adapted to maximize it (Lanyon and Sanson, 1986). Koalas use lateral jaw movements to crush leaves to a pulp before swallowing. They also have a disproportionately large oral cavity for the size of their skull which allows them to chew more food at any one time. Consequently, a decrease in brain size can be observed in the fossil record as more emphasis has been placed on the chewing process which causes an increase in the size of the masticatory muscles and their attachment sites (Grand and Barboza, 2001; Louys et al ., 2009). ). Grand and Barboza (2001) described the skull of a modern koala as “a chewing machine that houses a small brain.” Smith (1979) hypothesized that the brain size of koalas, which is one of the smallest brains relative to body size observed in any mammal, may be responsible for koalas' lack of adaptability and social skills. Smith suggested that because they are not opportunistic animals, like primates or carnivores, they are able to simply analyze whether or not what is put in front of them is a palatable food source or not, based on appearance, odor and moisture content without the need to evaluate the surrounding environment in detail. These findings are supported by Moore and Foley (2000) and Ellis et al. (2010). This lack of ability to process alternative environments, caused by small brain size, may further limit Koalas' ability to adapt to new habitats, as different species of the Eucalyptus genus may present differently, leading Koalas to reject perfectly suited food sources good based on their capabilities. differences in appearance (Moore and Foley, 2000). The toxic nature of the eucalyptus plant is partially caused by plant secondary metabolites (PSMs) and has made it an abundant food source for koalas, which have enhanced detoxification capabilities that allow them to digest it (Moore and Foley,.