The Red Fox is a small, slender animal with large pointed ears, an elongated muzzle, long slender legs, and a large bushy tail. The size varies dependent on individuals, and they are typically pale, yellowish-red, to deep, brownish-red on the upper parts of their body, and white or off-white on the underparts of their bodies. The Red Fox is scientifically referred to as the Vulpes vulpes, and is classed as a mammal.
The Fox can survive in arctic tundra – arid desert landscapes, being found in urban, alpine and semi-arid areas of Australia, and are typically found in agricultural landscapes, which offer a variety of food and shelter. Due to being a scavenger, red foxes will eat almost anything, preying on small land mammals and birds, and eating insects and fruits during the summer when other food is less abundant. Due to being an invasive species, there aren’t many natural predators for the fox, however fox cubs are vulnerable to birds of prey and dogs. There is also evidence that predation from Dingoes has suppressed local fox populations, as well as human intervention and droughts.
Males and females are both sexually mature at the age of one and reproduce both monogamously (a process of having one mate) and polygamously (a process of having multiple mates). Reproduction occurs from mid-June to the end of July, due to the infertility of males from September to March. Cubs are born during August and September in dens, and are usually born in litters of 3-5.
Cubs leave the den by the age of 8-10 weeks and begin to live on the surface, where they start to hunt for small animals and gain independence. A large percentage of female foxes (vixens) reproduce in the first year of their lives, with both males and females being sexually mature by 9-10 months of age. Red foxes are short lived mammals, with most foxes who survive their first year living to 2-3 years of age, around 60% of red foxes die before they are 1 year old.
Invasive species – a species that is non-native to the ecosystem and whose introduction is likely to cause economic or environmental harm. Invasive species can be plants, animals and other organisms such as microbes.
Introduced species – a species that has been moved by humans into an environment that it is not native to. The introduction of the species can be intentional or accidental, and can refer to animals, plants and micro-organisms.
Pest species – Animals or plants that bare harmful effects towards humans, their food production, and other aspects of human life. They pose threats to things such as crops, livestock and forestry.
The Red Fox fits into all three categories, being an invasive, introduced and pest, species. They were deliberately introduced by the Europeans during the 1850’s for hunting and other recreational activities and spread quickly throughout most of Australia. Due to their non-nativity and harmful effects on local ecosystems and human practices, the Red Fox is considered an invasive, pest species.
The Red Fox was purposely introduced in Victoria in 1855 for recreational hunting purposes. Originating from Europe, the Fox adapted well to the Australian environment, evading its hunters and quickly spreading throughout most of Australia, with populations becoming established in the wild by the 1870’s. Within 100 years the European Red Fox had spread across most of Australia, inhabiting over 75% of the land including Victoria, New South Wales, Queensland, South Australia and Mainland Australia. It currently inhabits most parts of the continent except for the far tropical north and a few off-shore islands, with current population numbers being estimated around 7.5 million. The Red Fox never fully established itself in Tasmania due to competition with the native Tasmanian Devil, however it was illegally reintroduced in 1999 and 2000, with eradication efforts beginning in 2002.
Many measures are being taken to reduce and eventually eradicate the Red Fox from Australian ecosystems. Preventing the spread of Foxes to new areas, such as islands is key to ensure the eradication of the European Red Fox, as they can often provide refugee habitats when mainland areas are being cleared. Current methods such as fencing, baiting and poisoning are being used throughout Western and Eastern Australia, to lessen and prevent the impact the Red Fox has on local ecosystems and human industries. In 1999, the Australian government developed the ‘Threat Abatement Plan for Predation by the European Red Fox’, which aimed to diminish the impact of predation by Red Foxes. The plan aimed to achieve this by; preventing foxes from inhabiting new areas, improving effectiveness of current management methods, promoting the recovery and maintenance of native species, and increasing understanding and awareness of Red Fox impacts.
The Red Fox is mainly unchallenged in Australian ecosystems, facing little competition, and mild predation from native Dingoes. It mainly preys on many small primary consumers, such as the Greater Bilby. However due to being a scavenger it also feeds on producers (plants) and animals in its own trophic level (such as Lizards and the Greater Stick-Nest Rat). The surplus killing methods the Red Fox exhibits puts many native species at risk, and has led to the extinction of many small mammals and ground birds. Foxes are essentially a species that reduce biodiversity within Australia, impacting the survival of native prey over large ecosystems. They do however prey on other invasive/pest species such as the rabbit, however this positive is little compared to the negative effects. Overall the Red Fox has a negative effect on the Australian environment, due to the damage it causes to local biodiversity and ecosystems.
The Red Fox quickly established itself in Victoria when it was introduced, and continued to spread across most of the country. This vast expansion across Australia has allowed the Red Fox to be successful within the local environments, and has contributed to the ineffectiveness of control methods, due to the widespread nature of the population. The Red Fox has a wide tolerance range, being able to live in many different environments and habitats, tolerating cold and warm ecosystems.
The Red Fox has developed many adaptations, leading to a wide range of tolerances to abiotic factors, such as temperature (as previously mentioned).
Structural adaptations have allowed the Red Fox to be a successful predator. The Red Fox utilizes a variety of senses, and has adapted both its hearing and sight to allow it to hunt successfully during the night time. Its hearing has evolved allowing it to pinpoint and locate sounds to within a degree of where they originated. This allows the Red Fox to detect its prey, before it can be visually recognized. Their eyes have also adapted to work better in low light, due to their retinas being dominated by rods (photoreceptive cells that do not produce colour or as sharp images, but allow for better visual recognition during low light). The hind legs are also longer than other canids, allowing for greater precision and propulsion when pouncing on prey, the preferred method of catching living food. These structural adaptations allow the Red Fox to be a diverse predator, being an effective nocturnal and diurnal hunter.
The Red Fox has developed a behavioral adaptation called catching, a process in which an animal stores food for later use and or consumption. During this process the Fox will catch and kill its prey, then store and camouflage it in a hole. If a hunt is unsuccessful, the Fox is injured, or there is an unreliable availability of prey, the Fox can retrieve food from a cache. If food were to become unavailable, the Red Fox would have a reliable source a food to maintain itself until availability increased.
These physiological, structural and behavioral adaptions allow for the Red Fox’s success in many different ecosystems. Thermoregulation allows the Red Fox to inhabit many different areas of Australia, ranging from the colder areas of Victoria to the warmer areas of mainland Australia. The structural adaptations make the Red Fox a fierce predator of many native animals such as the Greater Bilby, while behavioral adaptations like catching, allow the Red Fox to maintain itself during times of low food availability.
The Red Fox has adapted to many ecosystems and environments throughout the world, and has largely been successful due to its lack of specialist adaptations. Not being adapted to any particular ecosystem, but rather having a set of adaptations that allow its wide success, has seen the Red Fox become the most widely spread carnivorous mammal in the world.
One of the Red Fox’s most important physiological adaptations is Thermoregulation – the maintenance of a constant temperature of an organism independent of the temperature of the environment (defined by http://www.yourdictionary.com/ ). The Red Fox controls body temperature by, increasing blood flow and dilating blood vessels when it is warm, and decreasing blood flow and constricting blood vessels when it’s cold. Areas of short fur, which make up 1/3rd of the body’s surface area, also allow for heat dissipation. It is also inferred a separate brain cooling mechanism may be present, due to the difference in heat between the part of the brain responsible for heat control (the preoptic anterior hypothalamus) and the body. This thermoregulatory control allows the Red Fox to live in cold environments, as well as much warmer habitats.
he Red Fox has developed several biotic relationships within the Australian environment, however it is arguably the lack of fierce competition and predators that has allowed the Red Fox to establish itself. Developing relationships with small mammals and pest rabbits has allowed to Red Fox to maintain a consistent food supply. The past has shown that the Tasmanian Devil is too fierce a competitor for the Red Fox to maintain itself in Tasmania, however this isn’t a problem in the main continental areas where Tasmanian Devils are absent. Predation from Dingoes may suppress Fox numbers, however it does not pose any serious threat to the established populations.