THE MOUSTACHED TAMARIN AND EMPEROR TAMARIN

 

The moustached tamarin (Saguinus mystax) is a New World monkey and a species of tamarin. The moustached tamarin is named for the lack of coloring in the facial hair surrounding their mouth, appearing similar to a moustache. As with all New World monkeys, the moustached tamarin is found only in areas of Central and South America.

Moustached tamarins have a lifespan of about 20 years.^{[citation needed]} They are small, weighing 500 to 600 grams, and range in length from 30 to 92 centimeters, with adult females larger than males.^[3][4]

Moustached tamarin monkeys are characterized by white, curly hair around their mouth, similar to a moustache.^[5] Their face is flat with almond-like shaped eyes.^[5] Their ears are furry and large, and they have long, silky, body hair.^[5] They have a brownish-black body with a white moustache and white nose. They have tegula, which are claw-like nails, on each digit except their big toe.^{[citation needed]} These claws allow them to easily cling to trees while they feed. They have conical or spatulate incisors, which are used for cutting food, and are smaller than their canines.^[4] The lingual and labial sides of their incisors have a thick layer of enamel. Unlike most New World Monkeys, the moustached tamarin monkey has non-opposable thumbs and lacks a prehensile tail.^[5]

Heterozygous females, which make up about 60% of the female tamarin population, have trichromatic vision, while the remaining moustached tamarin population have dichromatic vision.^[3] Trichromatic vision is the capacity to see a broader range of color due to the presence of three color receptors in the retina, at the back of the eye, allowing them to distinguish between greens, blues and reds.^[3] Humans, as well as most species of Old World Monkeys, have trichromatic visual abilities; however, some female New World monkeys do as well. Dichromatic vision is a form of color vision in which only two of the primary colors are perceived.^[3] Trichromatic vision is an evolutionary adaptation that enables females to more easily find and identify fruit. Color vision is a contributing factor for leadership selection in troops.

Moustached tamarins are inhabitants of tropical rainforests in Brazil, Bolivia and Peru.^[4] They live in arid, upland forests in the Amazonian lowland, mostly occupying higher tree branches. The home range of moustached tamarins is between 25 and 50 hectares.^[3]

 

Ecology

Moustached tamarin in Serra do Divisor National Park, Acre, Brazil

Moustached tamarins are omnivorous, frugivorous and insectivorous. Their diet mainly consists of fruits, nectar, gum exudates, invertebrates and small vertebrates. Invertebrates include katydids, stick grasshoppers, and spiders.^[4] Vertebrates include lizards and frogs. Gum feeding is seasonal, however it is a dietary staple during dry and early wet seasons when other resources are scarce. Exudates supplement nutrients and balance mineral intake; which prevent the species from experiencing a range of detrimental effects from a low-calcium and high-phosphorus insectivorous diet. They display a highly opportunistic foraging pattern, and the ratio and variety of their comestibles depend on the availability in their geographical location. Moustached tamarins select trees by the amount of nectar they yield, rather than proximity to their home range. This higher volume of nectar makes the chosen trees more reliable because it allows them to feed for longer periods. Their remarkable spatial memory allows them to quickly recall the location of fruiting trees. Spatial memory is vital because it aids in the exploitation of a widely scattered set of feeding sites and minimizes effort in foraging.^[4]

The moustached tamarin monkey is a crucial seed disperser for many plant species as a result of their diverse diet. They spread the seeds of fruits they ingest, indirectly impacting forest regeneration and maintenance. They are opportunistic feeders, utilizing a wide range of plant resources, allowing them to disperse a variety of seed species, providing significant benefit to their ecosystem.^[4]

Moustached tamarins are territorial, however, they sometimes join with groups of brown-mantled tamarins (Leontocebus fuscicollis) and Geoffroy's saddle-back tamarin (Leontocebus nigrifrons).^[3] These species can cohabit because they have varying locomotor types, hunting techniques, support preference, food selection, and reside in different strata of their forest habitat.^[4] The brown-mantled tamarin and the moustached tamarin do not compete for the same resources. Sharing territory with another species facilitates predator avoidance, increasing survival chances for both groups. Having more eyes and ears provides greater protection.

Moustached tamarins are arboreal, diurnal,^[3] and precocial.^{[citation needed]} Tamarins walk and run on all fours, similar to squirrels and use their claws for stability. The moustached tamarin monkey exercises three types of locomotion. Symmetrical quadrupedalism is the most frequently used locomotion type, followed by asymmetric quadrupedalism, and leaping.^[4] The kind of leap depends on the layer of the forest they occupy. In the lower canopy “trunk-to-trunk” leaps are performed.^[3] These are jumps that are short and quick, only reaching a length of 1 to 2 meters.^[3] While standing on a medium or large-sized trunk, they propel themselves into the air and land on their front limbs on another trunk. They perform “bounding” leaps which allow them to cross between discontinuous trees, extending their legs farther out, reaching up to 2 meters.^[3] In the high canopy, they perform “acrobatic” leaps. These are longer leaps, reaching 5 meters or more, used to travel between treetops.^[3] While in the air, they use their tail to decelerate their body before landing on the crown of a nearby tree.

Moustached tamarin monkeys select densely foliated areas for resting and sleeping to best camouflage themselves because their small size makes them an easy target. Their main tactic is to avoid predation by attracting as little attention as possible. Their predators include eagles and other birds of prey, snakes, tayras, jaguarundis, ocelots and other wild cats.^[4]

Social grooming can be used to develop bonds. The moustached tamarins use their claws to detangle and comb one another's hair and remove parasites and dirt with their teeth and tongue.^[3] Social grooming is not equally exercised by members and the amount of grooming services given and received depends on the social position of the individual.

Scent marking is used to identify territory boundaries and to communicate with others.^[3] Females practice scent marking more frequently than males because it is also used in mate selection.^[3] The three types of scent marking are circumanal marking, suprapubic marking and sternal marking.^[5] Circumanal marking is the most commonly used type of scent marking.

Visual communication includes facial expressions, gestures, tonguing, and head-flicking. Tonguing is when a moustached tamarin moves its tongue across its lips. Head-flicking is when a moustached tamarin rapidly moves its head in an upward motion. Tonguing and head-flicking often co-occur and are used to communicate recognition, curiosity or anger.^{[citation needed]}

Group sizes are usually 4-8 individuals, excluding infants, and each group usually contains 1 or 2 adult females.^[3] However, groups have been observed to reach up to 15 individuals and solitary individuals have been encountered. Routinely, groups of moustached tamarins leave early in the morning to forage for food. They do not feed simultaneously. One of the adults positions themselves near the feeding site and scans the surroundings for predators to protect the group during mealtimes. They then retire at night in highly foliated areas to protect themselves from predators during slumber.^[3]

There is often strife between neighboring groups of moustached tamarins due to limited food resources, especially near large feeding trees.^[3] Vocal battles can arise, with long calls that consist of short syllables at a high frequency.^[6] This type of conflict occurs between groups that are 25 meters or more apart.^[6] Fights can be more aggressive however, often including alarm calls, visual contact, scent marking and a series of chases and retreats.^[6] Adult males attack, inducing combative and loud vocalizations, while subadults chase one another.^[3] Subsequently, there is a period of calm, and both groups forage for food and subadults examine the opposing group for mating opportunities.^[3] The frequency of aggressive encounters increases during the breeding season and the majority of copulations occur during or directly after an aggressive encounter.^[6]

Vocalizations allow moustached tamarins to distinguish between individuals, organize group movements, and ensure all members are accounted for. If individuals become separated, individuals of the same group will produce 2 to 3 second long vocalizations to indicate their location.^[4] These calls consist of repeated short, frequency-modulated syllables ranging from 8 to 12 kilohertz.^[4] In the morning, moustached tamarins make calls to each other to coordinate movement for the day towards specific foraging sites. Young tamarins also make vocalizations while they run and chase each other during play.

The reproduction season of the moustached tamarin monkey is November to March, during which the oldest female reproduces.^[4] Females go into oestrus for about 17 days.^[3] Their gestation period is about 145 days, after which females give birth.^[4] Other members of the group help to take care of the infants, allowing the female to give birth more than once a year. The eldest female frequently bears twins because they ovulate multiple ova during each reproductive cycle.^[3] The twins can be up to a quarter of the mother's size at birth. Females reach reproductive maturity at about 480 days, and males at 540 days.^[4] Both sexes migrate to a different group in adulthood to avoid the risk of inbreeding.^[3] Moustached tamarins practice a variety of mating systems: polyandry, polygyny or polygynandry.^[3] The mothers often receive help from up to 4 or 5 other members of the group. In polyandrous groups, the alpha male tolerates the presence of other males who can provide infant-care.^[3] Not having enough helpers can sometimes lead to infanticide by the mother.^[3]

The population trend for the moustached tamarin monkey is decreasing; however, the IUCN red list categorizes the moustache tamarin as least concerned.^[7] They have demonstrated an ability to adapt to disturbed habitats and proximity to human settlements. They can acclimate well to changes in environmental conditions and their ecosystem. Habitat destruction remains an inevitable threat to their population as for all species living in the Amazonian rainforest. However, their ability to adapt gives hope that this factor will not severely affect their population numbers.

Moustached tamarin monkeys are economically significant because they are used extensively in biomedical research, like other tamarin species. They have been used in the development of the hepatitis A vaccine.^{[citation needed]}

 

 

 

 

 Range of the Mustached Tamarin

 

 

  

 Range of the emperor tamarin

 

 

THE GEOFFROY'S TAMARIN

 

Geoffroy's tamarin (Saguinus geoffroyi), also known as the Panamanian, red-crested or rufous-naped tamarin, is a tamarin, a type of small monkey, found in Panama and Colombia. It is predominantly black and white, with a reddish nape. Diurnal, Geoffroy's tamarin spends most of its time in trees, but does come down to the ground occasionally. It lives in groups that most often number between three and five individuals, and generally include one or more adults of each sex. It eats a variety of foods, including insects, plant exudates, fruits and other plant parts. Insects and fruits account for the majority of its diet, but exudates are also important. But since its teeth are not adapted for gouging trees to get to the sap, it can only eat exudates when they are easily available.

Although a variety of reproductive methods are used, the most common is for a single adult female in the group to be reproductively active and to mate with multiple adult males in the group. After a gestation period of about 145 days, she gives birth to either a single infant or twins. Males contribute significantly to care of the infants. Sexual maturity is reached at about 2 years, and it can live up to 13 years. Geoffroy's tamarin is classified as being "near threatened" by the IUCN.

Like the other tamarins and marmosets, Geoffroy's tamarin is a New World monkey classified within the family Callitrichidae.^[2] In 2001, Colin Groves included the Callitrichids in the family Cebidae, which also includes capuchin monkeys and squirrel monkeys, but in 2009 Anthony Rylands and Russell Mittermeier reverted to older classifications which considered Callitrichidae a separate family.^[1][2] It is a member the genus Saguinus, the genus containing most tamarins.^[1][2] There are no recognized subspecies.^[1] In 1977, Philip Hershkovitz classified Geoffroy's tamarin as a subspecies of the cotton-top tamarin (Saguinus oedipus), which resides exclusively in Colombia, based on fur coloration, cranial and mandibular morphology, and ear size.^[5] However, more recent research indicates that the two taxa differ sufficiently to be considered separate species.^[6][7] According to genetic analyses, the two species diverged approximately 1.2 million years ago.^[8]

In common with other callitrichids (tamarins and marmosets), Geoffroy's tamarin is a small monkey.^[9] With a length of between 225 and 240 millimetres (8.9 and 9.4 in), excluding the tail,^[10] it is the smallest Central American monkey.^[9] The tail length is between 314 and 386 millimetres (12.4 and 15.2 in).^[10] Males have an average weight of 486 grams (17.1 oz), and females are slightly larger on average, with an average weight of 507 grams (17.9 oz).^[10] The fur on its back is variegated black and yellow, with pale legs, feet and chest.^[11][12] Its face is nearly bare, but the head has reddish fur with a triangle-shaped patch in the front of the head.^[11] The tail is chestnut-red and has a black tip.^[11][12]

Like all callitrichids, Geoffroy's tamarin is diurnal and arboreal.^[12] Unlike some other New World monkeys, it does come down to the ground occasionally.^[13] This is normally done only in special circumstances, such as to acquire certain foods or to get to a tree it cannot otherwise reach.^[14] Group size is generally between three and nine monkeys, with three to five being most common.^[10] Groups often consist of more than one adult of each sex.^[15] Adults of both sexes migrate between groups.^[15] Groups show some degree of territorial defense.^[9] Population densities on Barro Colorado Island in Panama range between 3.6 and 5.7 monkeys per square kilometer, but in other areas the population density can be as much as 20 to 30 monkeys per square kilometer.^[10] On average, Geoffroy's tamarin ranges 2061 meters per day.^[10] Home range size varies between 9.4 hectares and 32 hectares.^[3]

Communication occurs both through vocalization and by visual gestures.^[14] Vocalizations that have been recorded include whistles, twitters, trills, loud or soft sharp notes, sneezes and long rasps.^[10] Body postures and displays that reveal more of the white coloration, such as standing on hind legs and piloerection, tend to be associated with aggression.^[14] Females often signal willingness to mate by rapidly coiling their tails.^[14]

Geoffroy's tamarin was previously considered a subspecies of the similar cottontop tamarin, shown above.

Unlike squirrels, which often move through the canopy by climbing and descending vertical tree trunks, Geoffroy's tamarin generally avoids large vertical supports during travel. It prefers to move across thin branches, ascending and descending by long leaps. To the extent Geoffroy's tamarin uses large vertical supports for travel, it uses them most often for ascending rather than descending.^[16]

Geoffroy's tamarin generally avoids sympatric small and medium size monkey species such as the white-headed capuchin and the Panamanian night monkey. Avoidance is spatial with respect to the capuchin, and temporal in the case of the night monkey, since Geoffroy's tamarin is only active during daylight hours and the Panamanian night monkey is only active at night. Geoffroy's tamarin is rarely observed in the vicinity of squirrels, although this appears to be the result of the squirrels avoiding interactions with the larger tamarins. Geoffroy's tamarin generally attempts to escape when birds of prey approach, regardless of whether the bird presents a true danger. However, the tamarins ignore one bird of prey, the double-toothed kite, which sometimes follows the tamarins in an apparent effort to feed on small animals disturbed by the tamarins.^[14]

The diet of Geoffroy's tamarin is similar to some species of tyrant flycatcher birds in Panama, and they share similar vocalizations. The tamarins may use the flycatcher calls to help find favorable food sources. The flycatchers and tamarins have different patterns of activity, which minimizes competition for similar food sources. The flycatchers are most active shortly after dawn and tend to rest in the middle of the day. The tamarins do not become active until about 45 minutes after full daylight, but remain active for most of the remaining daylight hours until an hour or less before sunset.^[14]

Geoffroy's tamarin has a varied diet that includes fruits, insects, exudates (gums and saps), and green plant parts.^[10] The diet varies seasonally.^[10] A study by Paul Garber estimated that the diet was made up of 40% insects, 38% fruit, 14% exudates (almost entirely from Anacardium excelsum cashew trees), and 8% other items.^[10][16] Another study, on Barro Colorado Island, showed 60% fruit, 30% insects and 10% green plant parts, including large amounts of elephant ear tree (Enterolobium cyclocarpum) sap.^[10] Another study showed a diet about equally split between insects (mostly grasshoppers) and fruit.^[10] Unlike marmosets, tamarins do not have dentition adapted for gouging trees, so Geoffroy's tamarin eats sap only when it is easily accessible.^[3][16] It generally hunts for insects by making quick movements on thin, flexible supports.^[16] In contrast, it generally feeds on sap while clinging to large vertical tree trunks.^[16]

In one study, Geoffroy's tamarin drank water from the corollas of Ochroma limonesis flowers.^[10] However, it is believed to also drink from tree holes, similar to other tamarin species.^[10]

 

 Reproduction

A juvenile Geoffroy's tamarin, Gatun Lake, Panama

Geoffroy's tamarin can give birth throughout the year, but the birthing peak is from April to June.^[3][10] A single infant or twins can be born, although it is not uncommon for one of the twins to perish within the first few months.^[17] The gestation period is believed to be about 145 days, similar to the cottontop tamarin.^[3][10] The interbirth period ranges between 154 and 540 days, with an average of 311 days.^[10] The longer interbirth periods occur after twins.^[10] Infants weigh between 40 and 50 grams (1.4 and 1.8 oz) and are born fully furred.^[10] The infant's fur is colored differently than the parents'; the infant has black fur on the body and tail, with a beige blaze and white face.^[10] The infant coloration reduces the visibility of white, which is associated with aggressive displays by the species.^[14]

Both polyandrous and polygynous mating occurs, and males contribute heavily to parental care.^[17] But typically, only one adult female in a group is reproductively active, and reproductively active females mate with multiple males if given the opportunity.^[15] Males carry and groom infants more than females do.^[10] Older siblings may also contribute to infant care, although infants prefer to be carried by their parents than their siblings.^[10] Infants become mobile at 2 to 5 weeks, and begin eating solid food at 4 to 7 weeks.^[10] They are independent at 10 to 18 weeks and are fully weaned at 15 to 25 weeks.^[10] Geoffroy's tamarin becomes sexually mature at about 2 years, and can live up to 13 years.^[11]

Geoffroy's tamarin lives in various types of forest, including primary and secondary forest, and dry and moist tropical forest.^[11] In Panama, it prefers secondary forests with moderate humidity.^[14] It occurs in central and eastern Panama, with the range extending slightly west of the Panama Canal zone and has been observed as far west as Altos de Campana National Park.^[6] It is less common on the Atlantic coast of Panama than the Pacific coast, and is only abundant on the Atlantic coast in areas near the Canal zone that have been modified by man.^[6][14] It occurs in Metropolitan Natural Park, an urban park within Panama City.^[18] In Colombia, it occurs on the Pacific coast west of the Andes, south to the Rio San Juan.^[6] The eastern boundary of its range in Colombia was once thought to be the Rio Atrato, but has been reported further east, including the Las Orquídeas National Natural Park.^[6] Older sources sometimes report the species occurring in southern Costa Rica, but these are most likely erroneous.^[6][19]

The International Union for Conservation of Nature classifies Geoffroy's tamarin as being near threatened.^[3] The main threat is deforestation, which is causing population declines in some areas despite its ability to adapt to some modifications of its habitat.^[3] It is also sometimes hunted and captured for the pet trade in Panama.^[3] A 1985 study in Panama concluded that Geoffroy tamarin population densities are higher in areas where human access is limited.^[20] Human activity in Panama can have both positive and negative effects on Geoffroy's-tamarin populations. While hunting decreases the population, cutting mature forest for agriculture provides more areas of secondary growth, which is beneficial for the tamarin.^[14]

 

 

 

 

 

 

 

 

 

 

 

THE PIED TAMARIN

 

The pied tamarin (Saguinus bicolor), sometimes referred to as the Brazilian bare-faced tamarin, is a critically endangered species of primate found in a restricted area of the Brazilian Amazon Rainforest. It was named the mascot of Manaus, Brazil in 2005.^[3][5] The species is endangered due to the increasing size of the city of Manaus which is encroaching on their native habitat.

 

 Distribution and habitat

 

 

A New World monkey, it is found at the city limits of Manaus, the capital of the Amazonas state of Brazil and up to 35 km to the north and 100 km to the east.^[3] The main distribution is in the rio Cuieiras and rio Preto da Eva interfluvium. Pied tamarins are also found in the adjacent rio Preto da Eva and rio Urubu interfluvium, but are comparatively rare.^[6] There appears to be interspecific competition between the pied tamarin and the red-handed tamarin^[6] with the red-handed tamarin gradually displacing the pied tamarin from areas of its historical distribution.^[7] Therefore there are multiple threats to the long-term survival of the pied tamarin that stem from habitat destruction and from interspecific competition.

The pied tamarin is found in old-growth forests, sand forest and smaller secondary forest fragments. Their density is higher in secondary forest fragments than in primary forest.^[3]

 

Description

 

 

The pied tamarin's body measures 20.8–28.3 cm.; including the tail it measures 33.5–42.0 cm. The tamarin has a brown lower body and a fluffy white upper body. Their face is black and hairless, the reason for its nickname: the Brazilian bare-faced tamarin.

The pied tamarin does not have nails, but instead has claws that they adapted in order to quickly scale trees in order to retrieve food or escape predators. These nails also allow the tamarin to dig into tree bark and extract sap which they then eat.^[5]

Males weigh 428 grams (n = 4).^[8] Its life expectancy is approximately 10 years in the wild.^[9]

Individuals live in groups of 2 to 15 members with little intra-group competition. Average group size in the Reserva Florestal Adolpho Ducke is 4.8 individuals per group (n = 41),^[10] and other areas around Manaus reported mean group sizes of 6.19 ± 2.62 (n = 46).^[11] A tamarin group has a home range of 10-100 ha.

Tamarins are unlike most other mammals in the sense that the females are considered to be the dominant gender. In each group of individuals only one female is selected to breed and reproduce children. This individual is called the "Alpha Female" and reproduction by other females of the group is behaviorally suppressed.^[12] The gestation lasts 140–170 days and mothers typically give birth to twins. Although they generally give birth to twins the fact that only one female per group can produce offspring is a major cause in their reduced population size. Young tamarins are cared for primarily by the father and turned over to the mother only to nurse; however, the entire group helps with the care of the younglings that the alpha female birthed.^[5]

Tamarins are omnivorous, their diet consisting of fruit, flowers, nectar, insects, spiders, small vertebrates and bird eggs.^[6] Its natural predators are small cats, birds of prey, and snakes. In urban settings like Manaus, the main predators are domestic and feral cats and dogs. Because of the destruction of its natural habitat, the species is at risk which is why the species has landed on the IUCN red list for endangered species as well as the top 25 most endangered primates list in Brazil.^[13]

As of 2015, the pied tamarin is rated critically endangered by the IUCN Red List. The pied tamarin's population is expected to decline 80% by 2033 due to anthropogenic threats, competition with golden-handed tamarin (Saguinus midas) and disease. Within the Manaus area, pied tamarins are threatened by domestic and feral cats and dogs, electrocution from power lines, and the pet trade. Additionally, rural settlement and increasing livestock agriculture continue to encroach upon and degrade the pied tamarin's remaining habitat.^[3]

The pied tamarin is protected in some parts of its range, such as in Sumaúma State Park (52 ha), Adolfo Ducke Forest Reserve (18,240 ha) and less than half of Puranga Conquista Sustainable Development Reserve (157,807 ha). The Centro de Instrução de Guerra na Selva (CIGS)(115,000 ha) is an important protected area for the species, however it is not a conservation area but a military jungle training facility and so the area's status is uncertain.^[3] This organism is endangered due to its severe threat of species encroaching on its habitat and this will cause various issues to the ecosystem and environment.

Both European and American zoos and conservation services have pitched in financially to help out in saving the pied tamarin species.^[13] While there are only two areas in the world that are protected for the tamarins, and both are under 50 hectares, the conservation efforts have allowed for the reforestation of these places and the slow and uncertain return of the tamarins native habitat.^[14]

There is an established captive breeding program for the pied tamarin and an official studbook.^[15] As of 2009, there are 172 pied tamarins in captivity and all are registered property of the Brazilian government.^[3] Unfortunately for the tamarins, their captive breeding success rate is limited and thus it is difficult to resurrect the population artificially.^[16]

The tamarins live nearby the rapidly growing city of Manaus, and as the city's area increases in size, the tamarins habitat disappears. When they can avoid the busy automobile traffic and the electric power lines, the pied tamarin reside in the small sections of forest that still remain in Manaus.^[17]

Being an omnivore, the pied tamarins diet consists highly of plants. They pick up plant seeds when they eat and disperse them around their environment, thus bolstering their ecosystem.^[7] They also dine on small animals, which keeps the insect and amphibian populations in check. With the declining tamarin population, the issue becomes bigger than just the primates, but now turns into an ecosystem issue. There is no way to know for certain how the loss of the pied tamarin population will affect the Amazonian ecosystem, but there almost undoubtedly will be effects.^[5]

 

 

 

 

 

 The approximate range of the Pied Tamarin

 

 

 

 

 

 

 

 

 

THE CENTRAL BEARDED DRAGON

 

 

 

 Pogona vitticeps, the central (or inland) bearded dragon, is a species of agamid lizard occurring in a wide range of arid to semiarid regions of Australia. This species is very popularly kept as a pet and exhibited in zoos.

Description

Detail of the "beard"

Adults of this species can reach a total length of up to 60 cm (24 in), with the tail accounting for more than half. Sexes are not strongly dimorphic, but males can be distinguished from females as males have a wider cloacal opening, the base of the tail is wider, the head is usually larger with a larger beard and possess hemipenes.^[1] Males also have more pronounced femoral pores than females (these can be seen as waxy bumps on the underside of the back legs).^[2] Bearded dragons vary widely in colour, including brown, reddish-brown, red, yellow, white, and orange. They are capable of undergoing moderate changes in the shade of their colour to help regulate temperature. The specialized scales along both sides of the throat, neck, and head form many narrow spines which run down the side of the body to the tail. When feeling threatened, a bearded dragon will flatten its body against the ground, puff out its spiny throat and open its jaws to make itself appear larger. The bearded dragon is so named because of the pouch-like projection (also called the guttural pouch) on the underside of the neck and chin area which typically turns darker than the rest of the body. It also boasts spiny projections. Both of these characteristics appear similar to a human's beard. Males typically have a darker "beard" than females, and during mating season and courtship it will typically darken to near-black. The bearded dragon, like most agamid lizards, has strong legs which enable it to lift its body completely off the ground while it moves. This is done to reduce the heat taken in from the ground, as well as to increase the air flow over the belly to cool itself further.
Pogona vitticeps was first described by Ernst Ahl in 1926, who placed it in the genus Amphibolurus.^[3][4]
A studied conducted in 2014 established the existence of endogenous circadian rhythm in pigmentation changes in Pogona vitticeps. In other words, light and dark can influence the color changes of this kind of lizards. If exposed to light, the dorsal skin of the lizard becomes darker, and if exposed to darkness, it becomes lighter. Under constant darkness (i.e. in the subjective night), the lizards’ dorsal skin becomes the lightest.^[5]

 

 

Ecology and behaviour

Zoo Dvůr Králové Czech Republic

Taken at the Cincinnati Zoo

This dragon is native to the semiarid woodland, arid woodland, and rocky desert regions of Central Australia. They are skilled climbers, and often spend just as much time perching on tree limbs, fenceposts, and in bushes as they do on the ground. They spend the morning and early evening sunning themselves on exposed branches or rocks, and retreat to shady areas or underground burrows during the hottest parts of the afternoon.
Bearded dragons do not vocalize, except to hiss softly when threatened. Instead, they communicate through colour displays, posture, and physical gestures, such as leg waving and head bobbing. Bearded dragons are not social animals, but will sometimes gather in groups, especially in popular feeding or basking areas. At these times, a distinct hierarchy will emerge: the highest-ranking animals will take the best - usually the highest or sunniest - basking spots, and all other individuals arrange themselves lower down. If a low-ranking animal tries to challenge one of the dominant dragons, the dominant animal will demonstrate its superiority by bobbing its head and inflating its beard, at which point the challenger may signal submission by waving one of its front legs in a slow or fast circle. If the low-ranking dragon does not submit, it will return the head bob, and a standoff or fight may ensue.
The several different kinds of head bob gestures are:
 

 The male will only wave to show submission to a dominant male, whereas the female will wave, followed by a slow head bob, to show she is ready to mate. Gravid females will often refuse the advances of a male by chasing him and lying on his back.
When under direct attack, the central bearded dragon opens its mouth to display its yellow membranes and extend its beard.^[6] It darkens the colour of its skin and flattens its body, and will hiss and make small jumps towards the attacker. Bearded dragons are not known to attack humans.^[7]
Bearded dragons have been shown to be able to learn from watching the behaviour of conspecifics. An experiment demonstrated that after one individual was trained to open a door to reach a food item, most other bearded dragons watching this action were able to perform it as well.^[8]

 

 

Reproduction

Baby bearded dragon

The age of sexual maturity has not been measured, although it is estimated to be about one or two years.^[9] Body size and growth rates are more important than age when determining sexual maturity in bearded dragons.^[10] Males will become very aggressive towards each other and will assert their dominance by inflating their beards and through fast head bobbing. Breeding typically occurs in the early spring. Females will lay a clutch of 11-30 oblong-shaped eggs in a shallow nest dug in the sand. After being laid, the eggs are buried and are left unattended. The eggs will hatch approximately 60 to 80 days later, depending on the incubation temperature. In captivity, they can be incubated in a styrofoam fish box, but without a male lizard, the female's eggs will not be fertile. However, a female bearded dragon can retain sperm, and thus produce fertile eggs even after being separated from a male.
Courtship involves the male "head bobbing" to display dominance. If the female displays submissive behaviour, the male will use its mouth to grab the back of the female's head and the male will also wrap its front legs around the female's upper torso to keep her from moving. Copulation and insemination are quick. The gestation period averages about a month and a half.

 



A 2016 study showed that high-temperature incubation of eggs transforms genetically male individuals into functional females.^[11]
Normally their sex is determined genetically. Males have ZZ sex chromosomes, females ZW. However, when their eggs are incubated at temperatures above 32 °C (90 °F) some genetic males are born female. These females are fertile, sometimes producing more eggs than the ZW females. ^[12]

 

 Captive breeding

Exhibit at the Henry Doorly Zoo

Several of the Pogona genus are bred in captivity as pets; the two most popular are this species, P. vitticeps, and the western bearded dragon (Pogona minor minor).^[13][14] The bulk of captive-bred bearded dragons today are thought to have originated from stock illegally exported from Australia during the 1970s.^[15]
Captives worldwide are threatened by Agamid adenovirus, a virus that compromises the immune system of the dragon, and leads to death from other diseases. However, the majority of the infections are subclinical. Subclinically infected animals show no symptoms, but are active carriers of the disease and will infect other bearded dragons.
When the female is ready to lay eggs, she will generally stop eating and spend most of her time trying to dig.^{[citation needed]}