Dust bathing (also called sand bathing) is an animal behavior characterized by rolling or moving around in dust, dry earth or sand, with the likely purpose of removing parasites from fur, feathers or skin. [1] Dust bathing is a maintenance behavior performed by a wide range of mammalian and avian species. For some animals, dust baths are necessary to maintain healthy feathers, skin, or fur, similar to bathing in water or wallowing in mud. [2] In some mammals, dust bathing may be a way of transmitting chemical signals (or pheromones) to the ground which marks an individual's territory.
Birds crouch close to the ground while taking a dust bath, vigorously wriggling their bodies and flapping their wings. This disperses loose substrate into the air. The birds spread one or both wings which allows the falling substrate to fall between the feathers and reach the skin. The dust bath is often followed by thorough shaking to further ruffle the feathers which may be accompanied with preening using the bill.
The California quail is a highly sociable bird; one of their daily communal activities is a dust bath. A group of quail will select an area where the ground has been freshly turned or is soft. Using their underbellies, they burrow downward into the soil about 2–5 cm (1–2 in). [3] They then wriggle about in the indentations, flapping their wings and ruffling their feathers, causing dust to rise in the air. They seem to prefer sunny places in which to create these dust baths. An ornithologist is able to detect the presence of quail in an area by spotting the circular indentations left behind in the soft dirt, some 7–15 cm (3–6 in) in diameter.
Birds without a uropygial gland (e.g., the emu, kiwi, ostrich and bustard) rely on dust bathing to keep their feathers healthy and dry.
Dust bathing has been extensively studied in the domestic hen. In normal dust bathing, the hen initially scratches and bill-rakes at the ground, then erects her feathers and squats. Once lying down, the behavior contains four main elements: vertical wing-shaking, head rubbing, bill-raking and scratching with one leg. The dust collects between the feathers and is then subsequently shaken off which may reduce the amount of feather lipids and so help the plumage maintain good insulating capacity and may help control of ectoparasites. [4]
Hens exhibit preferences for dust bathing substrate. When given a choice between wood shavings, lignocellulose (soft wood fibre, pelleted), Astroturf mat without substrate, or food particles, the time spent dust bathing and number of dust baths were higher in lignocellulose compared with wood shavings, food particles, and Astroturf. The average duration of a single dust bath was longer in food particles compared with lignocellulose and wood shavings. Most vertical wing shakes and scratching bouts within a single dust bath were observed in lignocellulose. Bill raking occurred more frequently in wood shavings and lignocellulose in comparison to the other substrates. No differences in the relative durations of behavioral patterns within a single dust bath were found. [5] In contrast, other research shows that straw or wood-shavings were no more attractive than feathers as a substrate for dust bathing. [6]
Dust bathing is motivated by complex interactions between internal factors which build up over time, peripheral factors relating to the skin and feathers, and external factors, such as the sight of a dusty substrate.[ citation needed ]
The tendency to dust bathe fluctuates according to time of day, with more dust bathing occurring in the middle of the day [7] [8] which suggests some type of endogenous circadian rhythm of motivation. If birds are denied the opportunity to dustbathe, the tendency to dustbathe increases with time, suggesting a Lorenzian build-up of motivation. [7] [9]
Peripheral factors seem relatively unimportant in controlling dust bathing. Deprivation of dust bathing results in an increase in lipids on the feathers and a subsequent increase in dust bathing activity when this is allowed. [10] However, although it has been speculated that the function of dust bathing is probably removal of excess lipids on the feathers, [11] lipid accumulation as a major cause of dust bathing has not been proven. [12] A 1991 experiment by Van Liere, et al. of the Wageningen Agricultural University of the Netherlands could only increase the duration of dust bathing bouts marginally by spreading lipids, equivalent to 1–2 months' accumulation, on birds' feathers. Moreover, removal of the oil gland in chicks, which eliminated the main source of lipids, had no effect on subsequent dust bathing. [13] It therefore seems that the main effects of deprivation of dust bathing in hens act through a central mechanism and not a peripheral one. [14]
Environmental temperature is an important external factor; the frequency of dust bathing is greater at 22 °C (72 °F) than at 10 °C (50 °F). Addition of supplementary visible light also increases components of dust bathing, and when hens are individually housed, the presence of a group of hens dust bathing in an adjoining pen with a dust bath increased dust bathing compared with the amount occurring when the hens were absent from the pen., [14] i.e. there is a strong influence of social facilitation. [15]
Wrens and House Sparrows frequently follow a water bath with a dust bath (one reason to suspect an anti-parasite function for dusting). Overall, the amount of time and effort birds put into bathing and dusting indicates how critical feather maintenance may be. Keeping feathers functional requires constant care. [16]
Battery cages for domestic egg-laying hens usually have no dust bathing substrate. This is considered to be a welfare concern and as a consequence, dust bathing has been closely studied in domestic egg-laying hens. In the absence of substrate in cages, hens often perform sham dust bathing, a behavior during which the birds perform all the elements of normal dust bathing, but in the complete absence of any substrate. [17] [18] [19]
Many mammals roll in sand or dirt, presumably to keep parasites away or to help dry themselves after exercise or becoming wet. A sand roll, which is a stall or yard covered with deep sand, is traditionally included as part of stable complexes for use by racehorses after exercise. [20]
Dust bathing has been suggested to have a communicatory function in several mammals such as the common degu (Octodon degus), [21] the long-eared jerboa ( Euchoreutes naso ), [22] and possibly in Belding's ground squirrel as they leave a "pungent" odor in the dust bathing areas. [23] It has been suggested that wallowing (a behavior similar to dust bathing) may serve functions such as thermoregulation, providing a sunscreen, ecto-parasite control and scent-marking. [24]
Mammals that perform dust bathing include:
Beak trimming, or beak conditioning, is the partial removal of the beak of poultry, especially layer hens and turkeys, although it is also be performed on some quail and ducks. When multiple birds are confined in small spaces due to farming practices, they are more likely to hurt each other through pecking. Beak trimming aims to avoid damage done by pecking, although the practice is criticized by animal welfare organizations and banned in several European countries. Beak trimming is most common in egg-laying strains of chickens. In some countries, such as the United States, turkeys routinely have their beaks trimmed. In the UK, only 10% of turkeys are beak trimmed.
The common degu, or, historically, the degu, is a small hystricomorpha rodent endemic to the Chilean matorral ecoregion of central Chile. The name degu on its own indicates either the entire genus Octodon or, more commonly, just the common degu. Common degus belong to the parvorder Caviomorpha of the infraorder Hystricognathi, along with the chinchilla and guinea pig. The word degu comes from the indigenous language of Chile, Mapudungun, and the word dewü, meaning 'mouse' or 'rat'.
The domestic turkey is a large fowl, one of the two species in the genus Meleagris and the same species as the wild turkey. Although turkey domestication was thought to have occurred in central Mesoamerica at least 2,000 years ago, recent research suggests a possible second domestication event in the area that is now the southwestern United States between 200 BC and 500 AD. However, all of the main domestic turkey varieties today descend from the turkey raised in central Mexico that was subsequently imported into Europe by the Spanish in the 16th century.
Breed broiler is any chicken that is bred and raised specifically for meat production. Most commercial broilers reach slaughter weight between four and six weeks of age, although slower growing breeds reach slaughter weight at approximately 14 weeks of age. Typical broilers have white feathers and yellowish skin. Broiler or sometimes broiler-fryer is also used sometimes to refer specifically to younger chickens under 2.0 kilograms, as compared with the larger roasters.
Poultry farming is the form of animal husbandry which raises domesticated birds such as chickens, ducks, turkeys and geese to produce meat or eggs for food. Poultry – mostly chickens – are farmed in great numbers. More than 60 billion chickens are killed for consumption annually. Chickens raised for eggs are known as layers, while chickens raised for meat are called broilers.
Vacuum activities are innate fixed action patterns (FAPs) of animal behaviour that are performed in the absence of a sign stimulus (releaser) that normally elicit them. This type of abnormal behaviour shows that a key stimulus is not always needed to produce an activity. Vacuum activities often take place when an animal is placed in captivity and is subjected to a lack of stimuli that would normally cause a FAP.
Feather pecking is a behavioural problem that occurs most frequently amongst domestic hens reared for egg production, although it does occur in other poultry such as pheasants, turkeys, ducks, broiler chickens and is sometimes seen in farmed ostriches. Feather pecking occurs when one bird repeatedly pecks at the feathers of another. The levels of severity may be recognized as mild and severe. Gentle feather pecking is considered to be a normal investigatory behaviour where the feathers of the recipient are hardly disturbed and therefore does not represent a problem. In severe feather pecking, however, the feathers of the recipient are grasped, pulled at and sometimes removed. This is painful for the receiving bird and can lead to trauma of the skin or bleeding, which in turn can lead to cannibalism and death.
Abnormal behavior of birds in captivity has been found to occur among both domesticated and wild birds. Abnormal behavior can be defined in several ways. Statistically, 'abnormal' is when the occurrence, frequency or intensity of a behaviour varies statistically significantly, either more or less, from the normal value. This means that theoretically, almost any behaviour could become 'abnormal' in an individual. Less formally, 'abnormal' includes any activity judged to be outside the normal behaviour pattern for captive birds of that particular class or age. For example, running rather than flying may be a normal behaviour and regularly observed in one species, however, in another species it might be normal but becomes 'abnormal' if it reaches a high frequency, or in another species it is rarely observed and any incidence is considered 'abnormal'. This article does not include 'one-off' behaviours performed by individual birds that might be considered abnormal for that individual, unless these are performed repeatedly by other individuals in the species and are recognised as part of the ethogram of that species.
Sham dustbathing is a behaviour performed by some birds when kept in cages with little or no access to litter, during which the birds perform all the elements of normal dustbathing, but in the complete absence of any substrate. This behaviour often has all the activities and temporal patterns of normal dustbathing, i.e. the bird initially scratches and bill-rakes at the ground, then erects its feathers and squats. Once lying down, the behaviour contains four main elements: vertical wing-shaking, head rubbing, bill-raking and scratching with one leg. Normal dustbathing is a maintenance behaviour whose performance results in dust collecting between the feathers. The dust is then subsequently shaken off which reduces the amount of feather lipids and so helps the plumage maintain good insulating capacity and may help control of ectoparasites.
Toe pecking, an abnormal behaviour of birds in captivity, occurs when one bird pecks the toes of another using its beak. This behaviour has been reported in hens and ostriches. Studies have shown that hens exposed to toe pecking have significantly enlarged adrenal glands, indicating increased physiological stress. Hens exposed to toe pecking will step off a raised platform more quickly than control hens, possibly suggesting a heightened fear of elevation. They have also been reported to show depressive behaviour when afflicted by toe-pecking. The act of toe pecking leads to open wounds which are viable for infection and disease to develop. In severe forms, toe pecking can be classified as a cannibalistic behaviour and has been reported as a cause of mortality.
Animal welfare science is the scientific study of the welfare of animals as pets, in zoos, laboratories, on farms and in the wild. Although animal welfare has been of great concern for many thousands of years in religion and culture, the investigation of animal welfare using rigorous scientific methods is a relatively recent development. The world's first Professor of Animal Welfare Science, Donald Broom, was appointed by Cambridge University (UK) in 1986.
Cannibalism in poultry is the act of one individual of a poultry species consuming all or part of another individual of the same species as food. It commonly occurs in flocks of domestic hens reared for egg production, although it can also occur in domestic turkeys, pheasants and other poultry species. Poultry create a social order of dominance known as pecking order. When pressure occurs within the flock, pecking can increase in aggression and escalate to cannibalism. Cannibalism can occur as a consequence of feather pecking which has caused denuded areas and bleeding on a bird's skin. Cannibalism can cause large mortality rates within the flock and large decreases in production due to the stress it causes. Vent pecking, sometimes called 'cloacal cannibalism', is considered to be a separate form of cannibalistic pecking as this occurs in well-feathered birds and only the cloaca is targeted. There are several causes that can lead to cannibalism such as: light and overheating, crowd size, nutrition, injury/death, genetics and learned behaviour. Research has been conducted to attempt to understand why poultry engage in this behaviour, as it is not totally understood. There are known methods of control to reduce cannibalism such as crowd size control, beak trimming, light manipulation, perches, selective genetics and eyewear.
Chicken eyeglasses, also known as chicken specs, chicken goggles, generically as pick guards, and under other names, were small eyeglasses made for chickens intended to prevent feather pecking and cannibalism. They differ from blinders in that they allow the bird to see forward, whereas blinders do not. One variety used rose-colored lenses, as the coloring was thought to prevent a chicken wearing them from recognizing blood on other chickens, which may increase the tendency for abnormal injurious behavior. They were mass-produced and sold throughout the United States as early as the beginning of the 20th century.
Consumer demand tests for animals are studies designed to measure the relative strength of an animal's motivation to obtain resources such as different food items. Such demand tests quantify the strength of motivation animals have for resources whilst avoiding anthropomorphism and anthropocentrism.
Comfort behaviours in animals are activities that help maintain the pelage, feathers, integuement or musculoskeletal system and increase the physical comfort of the animal.
Social facilitation in animals is when the performance of a behaviour by an animal increases the probability of other animals also engaging in that behaviour or increasing the intensity of the behaviour. More technically, it is said to occur when the performance of an instinctive pattern of behaviour by an individual acts as a releaser for the same behaviour in others, and so initiates the same line of action in the whole group. It has been phrased as "The energizing of dominant behaviors by the presence of others."
Wallowing in animals is comfort behaviour during which an animal rolls about or lies in mud, water or snow. Some definitions include rolling about in dust, however, in ethology this is usually referred to as dust bathing. Wallowing is often combined with other behaviours to fulfil its purpose; for example, elephants will often blow dirt over themselves after wallowing to create a thicker "coating", or pigs will allow the mud to dry before rubbing themselves on a tree or rock to remove ectoparasites stuck in the mud.
Communal burrow refers to the habitat built by some species of mammals as a community habitat. There are some species that build burrows, but not communal burrows; and there are some species that live in communal groups, but do not construct burrows or any other type of habitat.
Therese Mary Foster is a New Zealand behavioural psychologist, and is professor emerita at the University of Waikato. Her research focuses on animal behaviour and behavioural analysis.