captive breeding and maintenance of Rough Knob-tailed Geckos Nephrurus amyae and N. asper Text by Rob Porter Introduction knob-tails and the rough knob-tails. Centralian Knob-tailed Gecko The latter group includes four spe- (N. amyae) Knob-tailed geckos are endemic cies, N. amyae, N. asper, N. sheai and to the more arid regions of Austra- N. wheeleri. The latter two species This is the largest species in the lia. There are a total of nine species, are restricted to Western Australia genus, with records of snout-vent some of which are further divided and the northwestern Northern Ter- lengths close to 140mm. Needless into subspecies. The genus can ritory and are poorly to say, the poor excuse of a tail does be roughly divided into two represented in cap- not add much to the overall length! groups; the smooth tivity. The former However, their size and robust build two species are place them amongst the largest Aus- more widely tralian geckos, at least by mass, with maintained weights exceeding 50 grams. Bed- and will be ford & Christian (1993) recorded one dealt with specimen of N. amyae (reported as in this ar- N. asper) at over 61gms. It is also the ticle. spiniest of the group, especially over the posterior part of the body and hind legs. Colouration is fairly consistent with an overall sandy brown to rusty brown background with scattered markings of a lighter shade. Some of the individual tubercles are light creamy-brown, especially on the flanks, often forming bands across the body, while others are slightly darker or the same as the background co- lour. There is usually a darker collar marking around the neck area. The head is often further marked with a reticulated pattern of thin dark lines. The underside is pale creamy-white. The eyes are large with a vertical pu- pil and tend to be greyish in colour and exquisitely patterned with deli- cate black lines. True to its name, the Centralian knob-tail is restricted to the red centre of Australia around the Alice Springs area, north to Barrow Creek in the Northern Territory. Here it in- habits open or lightly wooded coun- try on stony soils or rocky hillsides. The day is spent in shallow burrows or hiding beneath large rocks. Im- 6 6 may be maintained together with or without females in some cases. Ide- ally, a group of a pair or three geckos (one male and two females) would be housed together. These may be successfully kept in one enclosure all year around, with breeding occur- ring regularly every year. However, mediately after dusk the some keepers believe they achieve animals emerge to forage, better breeding success if sexes are stalking a wide range of in- kept apart for most of the year and sects, scorpions and other simply introduced for breeding at the lizards, including geckos, appropriate time. until the early hours of the An enclosure measuring around 60 morning. x 30 x 30cm will adequately house a pair of N. asper, a little larger for Queensland Knob- a trio. For N. amyae a bigger enclo- C. tailed Gecko sure is required, say 75 x 30 x 30 for (N. asper) a pair 100 x 30 x 30 for a trio. All The Cape York population differs in habitat, both N. amyae and N. asper knob-tails are terrestrial lizards so no Muchthat it maysmaller inhabit than heath land vegeta- are tough and hardy captives. As long vertical height is required. In fact, if its tiondesert as wellcousin, as woodlandthe or savan- as temperature extremes, especially a cage with relatively smooth sides is Queenslandnah. They species are widespread rarely and abun- at the upper end, are avoided, there used, e.g. a glass aquarium, no lid is exceedsdant over110mm northeastern snout- and central is no reason to believe these geckos required if the sides are over about ventQueensland. length. The colour would not happily survive in excess of 20cm as their robust built rather in- and pattern is also less 20 years in captivity. hibits any agile movements such as strikingCaptive in a dark Husbandry brown or Although normally solitary in the jumping. grey-brown with several wild, they appear to be relatively tol- Good ventilation is essential. Most bandsAs aacross reflection the ofbody. the arid and se- erant of other specimens housed in of the top of the enclosure should Thesevere banks characteristics may be ir of- their natural the same enclosure; even two males either be open or covered with regular, indistinct or even absent in some specimens. Lines of creamy-white tu- bercles are often present on the back and tail. The flanks become gradually lighter, eventually becom- ing creamy-white on the ventral surface. As with N. amyae, the head often has a black reticulated pat- tern, although this may be difficult to see in older or very dark lizards. Speci- mens from the northern part of the range often possess a more distinctly banded pattern and the colour may be an attrac- tive purplish brown. Activity patterns are similar to the Centralian knob-tail and the habi- tat is usually open, rocky woodland or stony plains. 7 7 mesh to permit efficient air circula- bulb is also provided at the same end. seen active during the day, especially tion. Ideally, this would be combined The combination of these two will N. amyae. with some mesh vents around the produce a heat gradient ranging from Knob-tails are not fussy eaters. enclosure sides nearer the base. This 32–33°C at the hottest point, down Almost any suitably sized insect is a will provide an excellent airflow, the to mid to low 20’s at the cooler end. potential food item. My animals are warmer air leaving through the top In winter temperatures can be safely maintained totally on a diet of cricket, being replaced by cooler fresh air en- lowered a further 10–12°C and this gut-loaded with rodent pellets and tering through the vents at the bot- cool period is important to ensure fresh vegetables. Cockroaches, grass- tom. successful reproduction the follow- hoppers, mealworms, pink mice and Fine sand, such as red desert, beach ing spring. Although ultraviolet light even other small lizards would all be or plasterer’s sand make ideal sub- is probably not essential to these ani- readily accepted. Feeding for adults strates. They are cheap, readily avail- mals, a Reptisun 5.0 tube, controlled takes place 2–3 times per week dur- able and easy to keep clean. A layer by a timer, is positioned 30cm above ing the warm months, once a month of approximately 4cm is provided for the substrate surface. This provides during cooler times. If temperatures rough knob-tails. They are not avid a strong, natural photoperiod, which drop below 18°C no food is offered. burrowers (unlike the smooth spe- is adjusted seasonally, as well as of- Juveniles are offered food every sec- cies) as long as other shelter is pro- fering potentially beneficial ultravio- ond day. Food is dusted with a good vided. Some keepers maintain their let light. The lizards are occasionally quality calcium/multivitamin powder rough knob-tails on a paper substrate quite successfully (Wagner & Lazik, 1996) and this is certainly better for hygiene purposes. However, I pre- fer a more natural cage covering and this also reduces cage maintenance. Once a week any droppings are re- moved from the sand surface, a task taking about a minute for each enclo- sure. Once every 2–3 months the substrate is totally replaced. Other furnishings include a glass water dish approximately 3cm in di- ameter and 2cm deep and two or three up-turned flower pot saucers of appropriate size with an entry hole cut in one side. The geckos will read- ily use these as a home site and by providing several in different areas of the cage the lizard can chose a warm, cool, moist or dry home. A flat rock is also included, which is positioned di- rectly over a heat pad. This provides a good thermoregulation area for the reptiles. A small amount of water is poured onto the sand on one side of one of the pot saucers once per week. This provides a moist, humid refuge if required by the animals. Suf- ficient water is added so that the sand almost dries out within the next 4-5 days. As well as a low wattage heat pad underneath one end of the enclosure, a 25 or 40 watt incandescent light B. 8 8 once per week and at other feeds Sexing adult rough knob-tailed geck- being visible through the abdominal only a calcium powder is used. Knob- os is relatively straightforward once body wall of the gravid female, the tails will readily learn to accept food the animals have reached around 12 sand beneath one home site is kept from forceps even during the day. months of age. Males are noticeably constantly moist by adding additional Keepers should endeavour to prac- smaller than females in length and water. This area will be utilised by tise this method as much as possible bulk in both species. They also pos- the female for an oviposition site. as it ensures each animal receives its sess a pair of hemipenal swellings at The eggs are usually buried some fair share of food and it also guaran- the base of the tail just anterior of the 30–100mm deep in the sand. Females tees that the food items is at its peak vent. Wagner & Lasik (1996) claim will continue to produce clutches of nutritionally when it is eaten.