Goat (feral or wild)

Common name: Goat (feral or wild)

Scientific name: Capra hircus

Origin: Asia

Feral goat with large horns, mix of black blonde and white long hair

Animal status

Goats (feral or wild) are declared as established pest animals in the state of Victoria under the Catchment and Land Protection Act 1994 (CaLP Act)

Read more about the classification of invasive animals in Victoria.

Populations

History of spread

Feral goats have been present in Australia since early European settlement, with wild populations becoming established because of accidental escape or deliberate release. Early populations were initially concentrated near settlement areas, but they have since spread across 35% of Australia and occur on many offshore islands.

Goats were introduced to many areas by early settlers, miners and railway construction gangs for meat and milk.

Cashmere and Angora goats were also introduced to Australia in the mid-1800s for the fibre industry. When this industry collapsed in the 1920s, many goats were abandoned in preference for wool which added to the feral population.

The mixed origins of Australia’s feral goats are reflected in the genetic diversity seen in wild populations.

The greatest numbers of feral goats occur in the arid and semi-arid pastoral regions of Queensland, New South Wales, South Australia and Western Australia. However, it appears their numbers are increasing in parts of the Great Dividing Range.

Distribution in Victoria

There is little information available regarding feral goat distribution and density in Victoria, but anecdotal information suggests their largest populations occur where large tracts of forested or semi-arid areas offer protection from predators. Feral goats have also been sighted in many state and regional parks and forests throughout Victoria.

Factors that influence feral goat distribution include food, water and shelter. Occurrence of parasites and diseases, and predators such as wild dogs are also influential.

Animal biology

Appearance

There are over three hundred distinct breeds of goat throughout the world, but the Australian feral goat population consists of a mix of Angora, Cashmere, Anglo-Nubian, British Alpine, Saanen and Toggenburg breeds.

Both male and female goats have distinctive curved or corkscrew shaped horns, although some may be hornless. Their coats vary widely depending on breed and so does their hair type with it being either short, long, curled, silky or coarse. Goats may also have wattles (hanging fleshy lobes) on the neck and beards.

An adult male goat is called a buck, the female is called a doe and juveniles are referred to as kids. Adult males may also be referred to as 'billies' and females as a 'nannies'. Adult goats weigh between 40 and 60 kg while kids weigh about 2.6 kg at birth. Male kids are heavier than females and this is a difference that they retain throughout their lives.

Behaviour

Feral goats are highly social animals that form family units typically consisting of an adult female goat and her recent offspring. Family social units associate together to form what is known as a herd.

Male kids eventually leave their mothers to form 'bachelor' herds with other similar aged males. Feral goat bachelor herds overlap with the female's home range during breeding periods but may range over much larger areas for the rest of the year. Feral goat home ranges can vary from one square kilometre to 600 square kilometres depending on resource availability.

Female goats leave the group to give birth in a protected place such as a rock overhang cave or dense vegetation. Goat kids can follow their mothers soon after birth, but many remain hidden for the first few days and are only visited by their mothers for feeding.

Feral goats are most active during the day and rest at night in regular camp sites. Herd dynamics varies depending on seasonal changes, birth rates and the movements of the male bachelor herds. Feral goats tend to use high or difficult-to-access areas as their night-time camp sites to minimise the risk of predation.

Feral goats often use sense of smell rather than sight to find food and detect predators. Therefore, they prefer to graze facing into the wind to detect scent.

Goats are reliant on access to water and their home range will revolve around it. The frequency at which goats drink is influenced by environmental conditions. Generally, a herd of feral goats is led by a dominant male, and he shares leadership with a dominant female who will usually outlast several dominant males throughout her time.

Adult male goats display dominance through a variety of contact and non-contact methods. Non-contact threats include staring, facing a rival with the chin down and horns forward, rushing or rearing. Encounters where physical contact occurs include pushing, head butting, engaging horns and rearing up and clashing. Other signs of dominance include horn size, physical condition and scent.

Feral goats are highly social animals that have complex systems of communication including smell, sight and sound. Alarm behaviour in feral goats is highly developed, making them difficult to drive/muster. When a female goat detects danger, she will stand rigid with ears towards the potential danger. Kids respond by running to the relative safety of the female. Female goats may also snort loudly and repeatedly to alert nearby goats. Depending on the threat, the group may flee, move away slowly, or return to their previous activities.

Diet

Feral goats are opportunistic browsers that generally select the highest quality foods available. They will eat:

grass
leaves
twigs
bark
flowers
fruit
roots
plant litter
seeds
fungi.

Despite their tendency to select high-quality foods, feral goats can eat most plant species in Australia including many that are toxic, spiny and bitter.

An average-sized goat requires between 2 and 4.5 litres of water per day, depending on temperature. Despite this, some goats in cooler and wetter climates can obtain most of their water from their food, meaning can survive in some areas with limited permanent fresh water.

Preferred habitat

Feral goats can survive where food, water and protection from predators is available. In Victoria, feral goats tend to occur in the semi-arid environments of the north-west and the mountainous areas of the Grampians, Alpine and East Gippsland regions.

Predators

Wild dogs and dingoes are the most significant predators of feral goats in Australia. Feral pigs foxes and large eagles may also prey upon feral goats, particularly goat kids.

Diseases and parasites

Feral goats are susceptible to many exotic livestock diseases that are not present in Australia including:

foot-and-mouth disease
scrapie
rinderpest
Rift Valley fever
rabies
blue tongue.

Feral goats are also susceptible to several endemic diseases currently found in Australia including:

Johne's Disease
Q fever
tetanus
leptospirosis
hydatids
pulpy kidney
blackleg
various parasitic worms of the gastrointestinal tract.

Reproduction

Feral goats can breed all year round, but breeding tends to peak during autumn.

Feral goat breeding is influenced by environmental factors including drought, population dynamics, food and water availability. Despite variations in breeding seasons, all sexually mature female goats commonly come into oestrus at about the same time.

Feral goats have a higher proportion of females than males, so population growth can be high. It is generally accepted that a population has the potential to double in size every 1.6 years, without human influence or control.

Female goats are sexually mature from six months of age and can produce young twice a year, with a gestation period of only 150 days. Twins and triplets are relatively common among domestic and in feral goat populations, but most feral goats tend to have singles or twins.

Dispersal

Dispersal of feral goats depends on availability of food, water and shelter. Feral goats prefer to maintain a small home range and traditional camp sites where possible, but they will disperse when food and water becomes scarce. Young female goats will stay with their family group throughout their lives, while males will leave these groups at puberty and join bachelor groups.

From day-to-day large herds may will separate into smaller subgroups during the day and re-unite at night at common camp sites.

Impact

Impact on ecosystems and waterways

Feral goats cause considerable environmental impacts through:

soil damage
over grazing
browsing.

As a selective browser, feral goats can drastically impact specific plant communities over a relatively short period.

Goats are also capable of climbing trees where branches and trunks are on suitable angles, enabling them to graze much higher than kangaroos or sheep. Even when adult trees can survive, goats will destroy seedlings affecting the rate of recruitment and limiting the survival of that plant community.

Feral goats compete with many animals for resources. Goat dung around water ways, together with goat carcasses that have fallen into the water, is likely to affect water quality.

Competition and land degradation by feral goats is listed as a key threatening process under the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

Agricultural and economic impacts

Feral goats are a major agricultural pest throughout Australia.

Economic losses can be split into four areas of costs:

to primary production
associated with exotic diseases
of land degradation caused by goats
to the public to manage goats.

In other Australian states, some costs can be recouped by mustering and selling feral goats. Due to lower numbers and difficult terrain, it’s generally not practised in Victoria.

The monetary value of economic losses in Victoria is unknown. However, the cost to Australia is estimated to be around $25 million per annum.

While feral goats are found mostly on public land in Victoria, they are also found on private property in some areas. Feral goats and domestic livestock have overlapping diets and habitats which can cause competition with domestic livestock for food, water and shelter. Feral goats can also out-compete and outlast sheep and kangaroos in time of drought.

Primary producers who own domestic goats may incur costs by having to prevent male feral goats from mating with their females. Foresters also incur costs to production caused by goat damage to their seedlings.

Feral goats are known to be susceptible to several diseases of livestock including Ovine Johne's Disease, foot-and-mouth, rinderpest, rabies and blue tongue. Unchecked wild herds could potentially play a major role in the spread of exotic disease if they are introduced into Australia.

Management

Recommended control measures for feral goats include:

trapping
shooting
mustering
exclusion fencing.

The department recommends integrated pest management using all suitable control measures implemented in coordinated manner at a landscape scale.

Read more about management and control of feral goats.

Image credits

Figures 1 to 4 courtesy of Jason Wishart

Page last updated: 18 Apr 2023