Fat-tailed Geckos are ectothermic, and require moderately high temperatures to survive and thrive. Fat-tailed Geckos usually prefer temperature ranging between 80-90 degrees Fahrenheit. As mentioned, the role of humidity is not well understood in these geckos, but they do shed their skin like other gecko species, and thus require moderate humidity on occasion to carry out the shedding process properly. The elevation of the habitats inhabited by these geckos averages 1000 m, and may be higher or lower than this depending on which areas within West Africa the gecko is found. In addition to temperature and humidity requirements, Fat-tailed Geckos are also accustomed to living in specific types of terrain within West Africa. They live in rocky woodlands and savannas and are adept at hiding beneath available surface debris or uninhabited burrows (Bartlett and Bartlett, 2009). Fat-tailed Geckos are adapted for rocky and uneven surfaces and given the fact that they are nocturnal, in daytime they will likely be found in various shelters (under rocks, in burrows or other make-shift hide outs) where they will hide and sleep. These specific burrows or shelters may also be favored by these geckos because they are territorial, thus this gives them a specific territory to inhabit and defend against other geckos. (Bartlett and Bartlett, 2009; Bauer, et al., 2006)
Fat-Tailed Geckos are terrestrial eublepharine geckos; they lack toe pads, and unlike so-called "true" gecko species (gekkoninae), they have true eyelids. These stocky geckos can weigh as much as 75 grams, and are usually around 8 inches (20 cm) in maximum length, though some adults may be smaller due to age, diet or gender. Fat-tailed Geckos tend to brown or tannish in color, with a variable pattern of light and dark blotches or broad bands across the upper back and tail. The patterns of these geckos can vary depending on their age. Some specimens may also show a central white strip that starts at the head and continues down the back and onto the tail. These striped geckos still retain the normal brown-banded color pattern possessed by most Fat-tailed Geckos. Another key feature of this species is that they seem to wear a permanent "smile" due to the shape of their jaw. Another unique characteristic of Fat-tailed Geckos is their bulbous "fat" tails. The tails can also possess differing forms; a common variation is a teardrop shaped tail that seems to mimic the shape of the gecko's head, which could be used as a defense mechanism to confuse predators in the wild. Another use for these tails is the storage of fat, which can provide energy when food is scarce. The health of Fat-tailed Geckos can be determined by the thickness of their tails; when healthy and able to find adequate prey, the gecko's tails can be around 1.25 inches thick or more.
Fat-tailed geckos display sexual dimorphism, with the males being on average larger than the females. Determining the sex of these geckos can be done by looking for the presence or absence of femoral pores on the underside of the gecko's tail. In comparing the areas immediately anterior and posterior to the cloacal opening (anus), sexually mature males will have a vaguely chevron-shaped series of enlarged preanal pores and a proportionately more bulbous tail base (Bartlett and Bartlett, 2009). ("Gecko", 2013; Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
Fat-tailed Geckos will lay eggs at various times throughout the year as long as the temperature is ideal (humidity may also play a factor in some cases). Females productivity will depend on their health and amount of nutrition that was available to them. Fertile eggs are moist when first laid, but soon become harder and almost chalky to the touch. Infertile eggs will remain very soft (Kaplan 2013).
Once eggs are laid, incubation time varies with temperature. The average incubation period is around 6-12 weeks, with higher temperatures rresulting in shorter times to hatching. After hatching, the young geckos can reach maturity in a little less than a years time. The young are essentially miniatures of the parents.
Fat-tailed Geckos exhibit temperature dependent sex determination. Experiments have been conducted testing the different ratios of males and females in different incubation temperatures. If the incubation temperatures are low (around 24 to 28 degrees C), the offspring produced will be predominately female. Higher temperatures (31-32 degrees C) produce mostly males, while temperatures of 29 to 30.5 degrees C will result in both sexes in roughly equal numbers.
Although the gender of Fat-tailed Geckos is determined by incubation temperatures, this does not seem to have a direct effect on the size of the newly hatched geckos. Hatchlings from differing nest temperatures did not significantly differ in mass or length at hatching. Fat-tailed Geckos do exhibit sexual dimorphism not only in terms of reproductive organs, but males are also larger than females. Hatchling growth however tends to be similar until about 350 days after hatching, then the males begin to diverge from the females in development (become larger and develop the male-specific femoral pores) (Viets,1993). (Bartlett and Bartlett, 1995; Bartlett and Bartlett, 2009; Kaplan, 2013; Viets, 1993)
Fat-tailed Geckos are a species in which males are larger than females; males tend to dominate and mate with several females throughout their breeding season. Females can lay multiple clutches of eggs during their breeding season depending on how many males mate with them during the season. Mating begins at the start of their breeding season (from November-March). During courtship, the male grabs the neck of the female, and holds tightly while proceeding to mate. Males will compete for females, and both genders are highly territorial. Fat-tailed geckos can be classified as polygynandrous (both genders have multiple mates during the breeding season) (Viets 1993; Badger 2006). (Badger, 2006; Bartlett and Bartlett, 2009; Viets, 1993)
Fat-tailed Geckos have a breeding season of around 5 months in length each year. During this time, female geckos can lay up to five clutches of eggs, though many will lay fewer clutches in a year. In captivity the incubation period for these geckos depends on the temperatures at which the eggs are kept. Lower temperatures (80-85 degrees Fahrenheit) will result in a longer gestation period compared to higher temperatures (88-90 degrees Fahrenheit). Once the gestation period is complete, geckos grow at equal rates (starting with a mass around 4 grams once they hatch) regardless of gender until they being to reach maturity around 8-11 months after hatching.
One interesting feature of Fat-tailed Gecko reproduction is that competition (or ability to acquire mates) is present in males of this species, but not among females. Due to the fact, larger animals are more likely to dominate smaller males and have greater reproductive success. The aggressive and territorial nature of these geckos most likely results in females that are more willing to mate with males that have secure territories and are able to keep other geckos away. Clutch sizes in females are fixed around 1-3 eggs, and because there is no reported advantage to producing larger or smaller eggs, females of this species do not face much competition compared to males. Being larger in size is only advantageous to male Fat-tailed Geckos. (Viets 1993) (Bartlett and Bartlett, 2009; Viets, 1993)
Females provision their eggs with energy (as yolk) prior to oviposition. There is no post-oviposition care of eggs or young in this gecko. Hatchling Fat-tailed Geckos, while fragile, emerge as precocial miniatures of the adults and can fend for themselves immediately. Even though few studies have looked at this species in the wild, extensive experience with breeding them in captivity certainly suggests that parental care does not extend post-egg laying. It has been documented that hatchling Fat-tailed Geckos are intimidated by the presence of older or adult geckos within the same area, and may not eat and become stressed if forced to stay in proximity (Kaplan 2013; Viets 1993). (Bartlett and Bartlett, 2009; Kaplan, 2013; Viets, 1993)
Although most knowledge about Fat-tailed Gecko longevity comes from captive breeding programs, some information about their lifespan in the wild is known. In captivity, if fed a proper diet and kept in a suitable environment, these geckos do very well and can live 15+ years, with the maximum perhaps about 20 years. The potential lifespan of these geckos in the wild, while not researched in depth, is thought to likely be similar to their lifespan in captivity, reaching around 10 to 15 years in their native habitats. Whether in captivity or in the wild, there are factors that could influence the longevity of these geckos. Poor nutrition or lack of good housing and care may reduce the lifespan of a captive gecko. In the wild these geckos are subject to predation, illness. or other factors that often lead to an early death. (Bartlett 2009; Viets 1993) (Bartlett and Bartlett, 2009; Viets, 1993)
Fat-tailed Geckos are territorial and thus is probably largely solitary and unlikely to be seen in groups. These are mobile creatures, but generally do not travel great distances. Fat-tails are a nocturnal species, meaning they are active at night (hunting, out of hiding etc...), and would likely be sleeping or hiding during the day. There has not sufficient research to determine if social hierarchies exist within this species, however, the geckos do exhibit some interesting social and hunting behaviors.
Although Fat-tailed Geckos are not thought to be very social creatures, they do exhibit unique behaviors that help to settle disputes with other geckos. Males can vocalize, and use a number of of quiet squeaks or clicks during territorial disputes. Males may use these sounds to warn off other males or even warn or attract females. A common behavior seen in many gecko species, including Fat-tailed Geckos, is the ability to lose and then regenerate the tail. Tail loss may occur for many reasons, and serves the purpose of enabling the gecko to escape predation. In Fat-tailed Geckos especially, the tail mimics the shape of the head, and may save the gecko from death during an attack from a predator. By attracting the predator to the expendable tail, the gecko can make a quick escape before the predator realizes they've grabbed the wrong end. The tail later regenerates within a few weeks. Tail loss is not without cost, as it does serve in energy storage and balance, but the ability to lose (autotomize) the tail has surely saved the lives of numerous geckos from predator attacks (Bartlett 2009).
Another use of the tail occurs especially during hunting for food. When a Fat-tailed Gecko is nervous or hunting prey, it elevates its tail and waves it sinuously. The specific purpose of tail wagging/waving is unknown, but many believe it is to distract potential prey or perhaps distract predators while the gecko is otherwise focused on its food. (Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
There is currently no data on the territory or hiome range sizes of wild Fat-tailed Geckos. These geckos have been mainly studied in captivity, and more research is needed to discover aspects of this gecko's life and home range in the wild. From studying and breeding these geckos in captivity it has been concluded that they are very territorial animals, thus two males should not be housed together. Females of this species may also compete, therefore it is best to house a single gecko alone unless breeding. As these geckos are territorial in captivity, it might be predicted that in their native environment the geckos defend small territories as well (Bartlett 2009; Bartlett 1997; Badger 2006). (Badger, 2006; Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
Little research has been conducted with this species in the wild and most information comes from observations on captive geckos. The most common way for this animal to communicate with others is by using vision. This species apparently perceives its environment mainly through sight and touch. This species is sexually dimorphic (males are larger than females) and may depend on visual cues to identify potential mates. Fat-tailed Geckos also rely on vision to find prey. As noted above, these geckos use vocalizations to ward off other geckos from a certain area or territory. Vocalizations seem to be reserved for settling territorial disputes. (Bartlett 2009).
As noted above, Fat-tails do display a unique behavior of tail wagging/waving, and although its purpose is not entirely known, it is thought to be used in hunting to distract or attract prey. The tail wagging may also be an additional way in which these geckos perceive their environments, by making vibrations (if the tail is contacting the ground) or making visual cues with their tails these geckos are able to attract or better hunt prey. (Bartlett 2009)
These geckos may also use odors and pheromones to interact with their environment and other geckos, but this has not been studied in this species. (Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
Fat tailed Geckos are apparently completely carnivorous, and are not known to consume any plant materials. They are primarily insectivores, feeding on various kinds of insects and other invertebrates within their habitats (for example different types of worms, crickets, possibly beetles or roaches etc...). Fat-tails are nocturnal, and thus (in their native habitats) hunt for various insects at night. Fat-tailed Geckos in captivity are usually fed insects that are mainly from two categories. They are fed crickets or various types of larval insects (mealworms, wax-worms, hornworms etc...). When kept in captivity (as pets) additional supplemental nutrients may also be needed in the gecko's diet to ensure that all of the required vitamins and minerals are obtained. This is accomplished by "dusting" crickets or other feeder insects with a calcium (or other vitamin powder) powder, or "gut loading" the insects. Gut loading the insects is the process in which feeder insects are fed a diet high in protein and other nutrients prior to feeding. In addition to these food sources, small frozen mice can are readily eaten by adult geckos. However. mice are given only rarely, as a treat and not a staple food in the gecko's diet (Bartlett 2009).
Fat-tailed Geckos also consume their shed skins. There has been research done on shed skin eating among various reptiles, and the main point of this consumption seems to be for recovering calcium and other vitamins found in the skin that would otherwise just be lost from the body. Shed skins represents a loss of energy and nutrients to the animals unless it is consumed. Geckos and many other reptiles shed skin very often, and thus must compensate for this loss in some way. Other hypotheses for this behavior have been noted, including the consumption of shed skin to reduce signs of their presence to predators; these predictions need further testing to be confirmed (Weldon et al. 1993). (Bartlett and Bartlett, 1995; Bartlett and Bartlett, 2009; Weldon, et al., 1993)
Known natural predators of Fat-tailed Geckos have not been well documented, and warrant further study. It is assumed that the predators of these geckos are likely similar to those recorded for other species of geckos, including various snakes and larger lizards such as monitor lizards. In addition to these, predators likely include various small mammals and birds native to West Africa (Gecko, 2013).
The use of the tail and tail autotomy in defense against predators has already been noted above. Other defenses include crypsis, as the varying brown and red color patterns likely assist the geckos in camouflage in their rocky habitats. Fat-tailed Geckos also spend a majority of their time hiding in dark places such as under rocks or burrows, so staying hidden and being able to find shelter from predators is another key adaptation for this species. ("Gecko", 2013; Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
Due to the limited research on Fat-tailed Geckos in the wild, and the fact that they are often reclusive in their native habitat, there is little known on all of the roles this species may have in its natural ecosystem. Fat-tailed geckos are not known to create habitats, but instead find shelter in abandoned burrows or other shelters. One definite effect these geckos have on their natural ecosystem is that they consume a variety of insect species (some which may be thought of as pests) and also serve as prey to many other species in the area as well. In addition to this, Fat-tailed Geckos can also serve as hosts for a variety of different parasites including various worms and other parasitic agents. (Bartlett 1997; Bartlett 2009) (Bartlett and Bartlett, 1997; Bartlett and Bartlett, 2009)
The main positive impact that these geckos have in regards to people is their value in the pet trade. Fat-tailed Geckos are available as pets throughout the world, and are one of the most popular reptiles on the market today. Fat-tails are known for being docile and easy to care for, and are potentially long-lived pets, making them one of the preferred reptile species for people wanting a non-allergenic pet. Captive breeding programs for this species assure that capture from the wild is unnecessary; they are readily available online and at almost any pet store (Bartlett 2009).
Although the main importance these geckos provide for humans is through the pet trade, they are sometimes known to be used for research and other studies. "This species is common in the pet trade and commercially purchased specimens from Bénin have also been used in laboratory studies, accounting for numerous museum specimens without specific locality data" (Bauer et al. 2006) Fat-tailed geckos, are very understudied in their natural environments, which explains the large amounts of specimens lacking information and other data. Research conducted with these geckos is not explained well, therefore in order to further knowledge on what these geckos contribute to humans, further research must be done with the species. (Bartlett and Bartlett, 2009; Bauer, et al., 2006)
Fat-tailed Geckos are too small to offer any threat to humans, and do not cause any conceivable economic or agricultural damage.
Fat-tailed Geckos have been evaluated by the IUCN Red List, and are listed as "least concern". According to IUCN, they are considered as least concern because they are widespread throughout their natural habitat and are not threatened by human activity. Intensive agriculture and collection for the pet trade are the only potential threats. In addition to this, the IUCN states that it is unknown whether or not any action is needed to conserve this species due to the fact that they naturally occur in protected areas. This species of gecko is not specifically mentioned on CITES, however the family in which they belong to (Gekkonidae) is listed under Appendix I. This species is not found on the US federal list or the State of Michigan list. (IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2., 2013)
Katherine Gerster (author), Michigan State University, James Harding (editor), Michigan State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
uses sound to communicate
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
An animal that eats mainly insects or spiders.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
one of the sexes (usually males) has special physical structures used in courting the other sex or fighting the same sex. For example: antlers, elongated tails, special spurs.
uses touch to communicate
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.
A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
young are relatively well-developed when born
2013. "Gecko" (On-line). Animals A-Z. Accessed October 29, 2013 at http://a-z-animals.com/animals/gecko/.
Badger, D. 2006. Lizards. Minnesota: Voyageur Press.
Bartlett, R., P. Bartlett. 1995. Geckos. New York: Barron's Educational Series Inc.. Accessed October 21, 2013 at http://books.google.com/books?id=k8uCOlAXDLAC&pg=PA74&dq=Hemitheconyx+caudicinctus&hl=en&sa=X&ei=BCtKUuzGKena2wWgqICwBQ&ved=0CC0Q6AEwAA#v=onepage&q=Hemitheconyx%20caudicinctus&f=false.
Bartlett, R., P. Bartlett. 2009. Leopard and Fat-Tailed Geckos. New York: Barron's Educational Series Inc.. Accessed October 21, 2013 at http://books.google.com/books?id=ruV4njkeiU8C&printsec=frontcover&dq=african+fat-tailed+gecko&hl=en&sa=X&ei=QipKUvfOA-mc2QWG2oHwBA&ved=0CDgQ6AEwAA#v=onepage&q=african%20fat-tailed%20gecko&f=false.
Bartlett, R., P. Bartlett. 1997. Lizard Care from A to Z. New York: Barron's Educational Series Inc..
Bauer, A., S. Tchibozo, O. Pauwels, G. Lenglet. 2006. A review of the gekkotan lizards of Bénin, with the description of a new species of Hemidactylus (Squamata: Gekkonidae). Zootaxa, 1242: 1-20.
Boozalis, T., L. LaSalle, J. Davis. 2012. Morphological and biochemical analyses of original and regenerated lizard tails reveal variation in protein and lipid composition. Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology, 161/1: 77-82.
Hatcher, R. 2013. "Fat-Tailed Gecko" (On-line). Herp Care Collection. Accessed October 21, 2013 at http://www.anapsid.org/fattailgecko.html.
IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2., 2013. "
IUCN Red List of Threatened Species" (On-line). Accessed May 06, 2014 at www.iucnredlist.org.
Kaplan, M. 2013. "Leopard and African Fat-Tailed Gecko Breeding, Egg Laying and Incubation" (On-line). Herp Care Collection. Accessed October 21, 2013 at http://www.anapsid.org/lepgeckbreed.html.
Viets, B. 1993. "Lizard reproductive ecology: Sex determination and parental investment" (On-line). ProQuest. Accessed October 21, 2013 at http://search.proquest.com.proxy1.cl.msu.edu/docview/304036438/abstract?accountid=12598.
Weldon, P., B. Demeter, R. Rosscoe. 1993. A Survey of Shed Skin-Eating (Dermatophagy) in Amphibians and Reptiles. Journal of Herpetology, 27/2: 219-228. Accessed October 21, 2013 at http://www.jstor.org/stable/1564942.