Sunning or basking, sometimes also known as sunbathing, is a thermoregulatory or comfort behaviour used by humans, animals, especially birds, reptiles, and insects, to help raise their body temperature, reduce the energy needed for temperature maintenance or to provide comfort. They may also have additional functions of ridding animals of ectoparasites, bacteria, or excess moisture.
Birds adopt special postures when sunning, these may include spreading out their feathers, flattening their body on soil, showing either their upper parts to the Sun or facing the Sun. Some authors separate the behaviours into sun-basking and sun-exposure – the former term used when the behaviour is strictly thermoregulatory in function while the latter term may be more appropriate if the behaviour serves functions other than raising body temperature. [1]
In some species, the sunbathing posture is adopted in very hot weather and the birds sometimes stay in close contact with hot soil. Birds may fluff up their feathers, expose their preen-gland, lean to one side and so on. The wings may be turned inside out as in the boobies or held in delta-wing positions as in herons and storks or held outspread as by vultures. [1] [2] Swallows were observed to indulge in the activity for very short durations and this appeared to induce hyperthermia leading to them gaping to cool. Observers have suggested that the purpose might not be thermoregulation in these cases. [3] A theory that birds obtained vitamin D by allowing precursors in the preen-gland secretions to be converted by ultraviolet radiation is considered to be unsupported. [4] [5] Large soaring birds such as Gyps vultures may use sun-bathing postures to help in stiffening their feathers as they used such postures only prior to flying and not during the early morning hours. [6] Another theory is that ectoparasites may be killed or forced to move away from inaccessible parts of the body to more accessible areas where they can be removed through preening. This is supported by the observation that sunning is often followed by preening. [7] [8] Feather-degrading bacteria are known to be killed by the action of sunlight. [9]
Basking is common to most active diurnal reptiles. Lizards, crocodiles, terrapins, and snakes routinely make use of the morning sun to raise their body temperature. Freshwater turtles and terrapins have been found to bask and raise their body temperature close to the highest temperatures that they can tolerate. [10]
Some mammals and most humans make use of the sun to warm their body or to provide comfort. It has been suggested that early mammals, which may have been small and nocturnal, may have basked to rapidly warm their bodies based on observations made on a nocturnal marsupial, Pseudantechinus macdonnellensis . [11]
Many insects require the morning sun to come out of nocturnal torpor and become active. In the higher latitudes, many insects have black on their wings or body to enhance their heat acquisition. This trend for increased darkness in higher latitudes is especially well marked in the Lepidoptera although the trend may be more general and unrelated to thermoregulation as it is also seen in nocturnal Geometridae. [12]
A vulture is a bird of prey that scavenges on carrion. There are 23 extant species of vulture. Old World vultures include 16 living species native to Europe, Africa, and Asia; New World vultures are restricted to North and South America and consist of seven identified species, all belonging to the Cathartidae family. A particular characteristic of many vultures is a bald, unfeathered head. This bare skin is thought to keep the head clean when feeding, and also plays an important role in thermoregulation.
The Eurasian griffon vulture is a large Old World vulture in the bird of prey family Accipitridae. It is also known as the griffon vulture, although this term is sometimes used for the genus as a whole. It is not to be confused with the Rüppell's griffon vulture and Himalayan griffon vulture. It is closely related to the white-backed vulture.
The Himalayan vulture or Himalayan griffon vulture is an Old World vulture native to the Himalayas and the adjoining Tibetan Plateau. It is one of the two largest Old World vultures and true raptors. It is listed as Near Threatened on the IUCN Red List. It is not to be confused with the Eurasian griffon vulture, which is a similar and sympatric species.
The white-rumped vulture is an Old World vulture native to South and Southeast Asia. It has been listed as Critically Endangered on the IUCN Red List since 2000, as the population severely declined. White-rumped vultures die of kidney failure caused by diclofenac poisoning. In the 1980s, the global population was estimated at several million individuals, and it was thought to be "the most abundant large bird of prey in the world". As of 2021, the global population was estimated at less than 6,000 mature individuals.
Rat snakes are members – along with kingsnakes, milk snakes, vine snakes and indigo snakes – of the subfamily Colubrinae of the family Colubridae. They are medium to large constrictors and are found throughout much of the Northern Hemisphere. They feed primarily on rodents. Many species make attractive and docile pets and one, the corn snake, is one of the most popular reptile pets in the world. Like all snakes, they can be defensive when approached too closely, handled, or restrained. However, rat snake bites are not dangerous to humans. Like nearly all colubrids, rat snakes pose no threat to humans. Rat snakes were long believed to be completely nonvenomous, but recent studies have shown that some Old World species do possess small amounts of venom, though the amount is negligible relative to humans.
Torpor is a state of decreased physiological activity in an animal, usually marked by a reduced body temperature and metabolic rate. Torpor enables animals to survive periods of reduced food availability. The term "torpor" can refer to the time a hibernator spends at low body temperature, lasting days to weeks, or it can refer to a period of low body temperature and metabolism lasting less than 24 hours, as in "daily torpor".
Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. A thermoconforming organism, by contrast, simply adopts the surrounding temperature as its own body temperature, thus avoiding the need for internal thermoregulation. The internal thermoregulation process is one aspect of homeostasis: a state of dynamic stability in an organism's internal conditions, maintained far from thermal equilibrium with its environment. If the body is unable to maintain a normal temperature and it increases significantly above normal, a condition known as hyperthermia occurs. Humans may also experience lethal hyperthermia when the wet bulb temperature is sustained above 35 °C (95 °F) for six hours. Work in 2022 established by experiment that a wet-bulb temperature exceeding 30.55°C caused uncompensable heat stress in young, healthy adult humans. The opposite condition, when body temperature decreases below normal levels, is known as hypothermia. It results when the homeostatic control mechanisms of heat within the body malfunction, causing the body to lose heat faster than producing it. Normal body temperature is around 37°C (98.6°F), and hypothermia sets in when the core body temperature gets lower than 35 °C (95 °F). Usually caused by prolonged exposure to cold temperatures, hypothermia is usually treated by methods that attempt to raise the body temperature back to a normal range. It was not until the introduction of thermometers that any exact data on the temperature of animals could be obtained. It was then found that local differences were present, since heat production and heat loss vary considerably in different parts of the body, although the circulation of the blood tends to bring about a mean temperature of the internal parts. Hence it is important to identify the parts of the body that most closely reflect the temperature of the internal organs. Also, for such results to be comparable, the measurements must be conducted under comparable conditions. The rectum has traditionally been considered to reflect most accurately the temperature of internal parts, or in some cases of sex or species, the vagina, uterus or bladder.
An ectotherm, more commonly referred to as a "cold-bloodedanimal", is an animal in which internal physiological sources of heat, such as blood, are of relatively small or of quite negligible importance in controlling body temperature. Such organisms rely on environmental heat sources, which permit them to operate at very economical metabolic rates.
Anting is a maintenance behavior during which birds rub insects, usually ants, on their feathers and skin. The bird may pick up the insects in its bill and rub them on the body, or the bird may lie in an area of high density of the insects and perform dust bathing-like movements. The insects secrete liquids containing chemicals such as formic acid, which can act as an insecticide, miticide, fungicide, or bactericide. Alternatively, anting could make the insects edible by removing the distasteful acid, or possibly supplement the bird's own preen oil. Instead of ants, birds can also use millipedes. More than 200 species of bird are known to ant. A possibly related behaviour, self-anointing, is seen in many mammals.
The violet-green swallow is a small North American passerine bird in the swallow family. These aerial insectivores are distributed along the west coast from Alaska to Mexico, extending as far east as Montana and Texas. With an appearance very similar to the tree swallow, these individuals can be identified by the white rump side-patches that appear to separate their green back and purple tail. Violet-green swallows are secondary cavity nesters, found in a number of habitats including deciduous and coniferous forest. In addition to nesting in tree holes within these habitats, they are also widely observed nesting in the cracks of large cliffs.
Grooming is the art and practice of cleaning and maintaining parts of the body. It is a species-typical behavior.
The tawny frogmouth is a species of frogmouth native to the Australian mainland and Tasmania and found throughout. It is a big-headed, stocky bird often mistaken for an owl due to its nocturnal habits and similar colouring.
The uropygial gland, informally known as the preen gland or the oil gland, is a bilobed sebaceous gland possessed by the majority of birds used to distribute the gland's oil through the plumage by means of preening. It is located dorsally at the base of the tail and is greatly variable in both shape and size. In some species, the opening of the gland has a small tuft of feathers to provide a wick for the preen oil. It is a holocrine gland enclosed in a connective tissue capsule made up of glandular acini that deposit their oil secretion into a common collector tube ending in a variable number of pores (openings), most typically two. Each lobe has a central cavity that collects the secretion from tubules arranged radially around the cavity. The gland secretion is conveyed to the surface via ducts that, in most species, open at the top of a papilla.
The obelisk posture is a handstand-like position that some dragonflies and damselflies assume to prevent overheating on sunny days. The abdomen is raised until its tip points at the sun, minimizing the surface area exposed to solar radiation. When the sun is close to directly overhead, the vertical alignment of the insect's body suggests an obelisk.
Dust 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. 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. In some mammals, dust bathing may be a way of transmitting chemical signals to the ground which marks an individual's territory.
Urohidrosis is the habit in some birds of defecating onto the scaly portions of the legs as a cooling mechanism, using evaporative cooling of the fluids. Birds' droppings consist of both feces and urine, which are excreted together through the cloaca.
Insect thermoregulation is the process whereby insects maintain body temperatures within certain boundaries. Insects have traditionally been considered as poikilotherms as opposed to being homeothermic. However, the term temperature regulation, or thermoregulation, is currently used to describe the ability of insects and other animals to maintain a stable temperature, at least in a portion of their bodies by physiological or behavioral means. While many insects are ectotherms, others are endotherms. These endothermic insects are better described as regional heterotherms because they are not uniformly endothermic. When heat is being produced, different temperatures are maintained in different parts of their bodies, for example, moths generate heat in their thorax prior to flight but the abdomen remains relatively cool.
Comfort behaviours in animals are activities that help maintain the pelage, feathers, integuement or musculoskeletal system and increase the physical comfort of the animal.
Self-anointing in animals, sometimes called anointing or anting, is a behaviour whereby a non-human animal smears odoriferous substances over themselves. These substances are often the secretions, parts, or entire bodies of other animals or plants. The animal may chew these substances and then spread the resulting saliva mixture over their body, or they may apply the source of the odour directly with an appendage, tool or by rubbing their body on the source.
Preening is a maintenance behaviour found in birds that involves the use of the beak to position feathers, interlock feather barbules that have become separated, clean plumage, and keep ectoparasites in check. Feathers contribute significantly to a bird's insulation, waterproofing and aerodynamic flight, and so are vital to its survival. Because of this, birds spend considerable time each day maintaining their feathers, primarily through preening. Several actions make up preening behaviour. Birds fluff up and shake their feathers, which helps to "rezip" feather barbules that have become unhooked. Using their beaks, they gather preen oil from a gland at the base of their tail and distribute this oil through their feathers. They draw each contour feather through their bill, nibbling it from base to tip.