Nephrurus Laevissimus (Smooth Knob Tailed Gecko) is a solitary species of terrestrial gekkonid which is primarily endemic in the arid regions of the Australian continent from Southern Northern Territory to Northern South Australia and incorporating the Western Australian region. The average captive bred female specimen has a snout to vent length of 2.6″ (61 mm), while the male is 2″ (52mm) in length.
This species in the Nephrurus genus is not widely kept in captivity but is becoming more popular with experienced breeders only due to a sustainable percentage of specimens having been successfully bred to cater for demand. I believe there are more enthusiasts who endeavor to keep this species but due to its finicky and somewhat skittish behavior had deterred many individuals from adding this unique species to their collections.
After a considerable amount of time in researching this species behavioral pattern, it has come to my opinion that they can be catered for inexpensively and easily as long as some major factors are considering in their husbandry.
Originally when I first acquired Nephrurus Laevissimus as part of my research I was advised of its nature and felt that this was, in fact, the challenge I was looking for, even though many a breeder had advised me that the most challenging part of their husbandry would be accustoming a typical middle to southern state species to the humid and hot temperatures of Tropical North Queensland.
Typical requirements for sub-adult or adult Nephrurus Laevissimus was to accommodate each specimen separately in its enclosure except when introducing the male to the female for breeding purposes and endeavoring to have an enclosure that mimicked the species native origin or the conditions it was accustomed to. This setup incorporated the use of heat cords and glass tanks that had the capacity to hold up to 25cm of a deep substrate on the heated moist end which slowly flowed down to a dry substrate side with a depth of 12–15cm. These requirements were to reduce stress or anxiety by allowing them to burrow to realistic depths as is typical in nature, particular when gravid females were about to lay.
I successfully incorporated these methods into their husbandry and further added the extra security by placing black contact around the outside of all the enclosures so that visual concerns from outside the enclosures were eliminated. The ambient temperatures are set at 77-79°F (25–26°C) during the summer months with a hot end reaching a maximum temperature of 80°F (30°C) 24/7 during both summer and winter months. The only variance during the winter months was dropping the ambient temperature so to mimic natural temperature patterns, also reducing daylight hours during the winter period.
Accustomed to the fore-mentioned methods and taking visual notes on the individual’s behavior during both day and night hours made one start to think, are they accustomed to these conditions due to a natural built-in mechanism or due to their previous catered conditions?
The progeny would be the key to gathering information and determining whether I was correct in my assumptions. During the breeding season from October 2006 through to March 2007 I had produced a total of 22 fertile eggs from 3 adult specimens. On average each egg measured a length of 3/4-1″ (17–18mm) and a width of 1/2″ (9–10mm). All eggs predominately were always laid by the females at the base of the deep moist heated substrate end which was a chore having to dig down 9&3/4″ (25cm) of the substrate to collect them. Collection always took place within the first 24 hours of being laid. From one single mating, the females cycled and laid every 14–16 days and produced an average of 4 clutches within that season.
I wondered whether slowing the incubation process down could or would produce more vigorous hatchlings with the determination to feed. I incubated with the use of vermiculite at a ratio of 250ml to 25mls of water and placed individual clutches into air tight containers and incubated at a lower temperature predominately 73-75°F (23–24° Celsius). At these temperatures, the incubation period was extended, and typically juveniles were hatching out between 75–85 days.
All individual juveniles were housed in small glass or plastic containers measuring 14cm x 9cm with white sand as a substrate measuring a depth of only 1cm with a small plastic hide (plastic hides are ideal as crickets find it hard to climb and hide on the top of the inside, thus easy access to finding food for juveniles).
These small enclosures were completely covered on the outsides by black contact and then 1/3 of the containers placed on 25W heats cords. The substrate above the heat cord was constantly kept moist, and 2–3 small crickets were introduced with the first part of the hopper legs being trimmed to slow them down for easy access.
Crickets were offered within 24–48 hrs from hatching and I found juveniles would eat before going through their first shed. Small crickets were consistently offered and were devoured religiously, even though on introducing crickets made many specimens seek refuge, it eventually made them curious and kept them continually enticed and entertained. They seem to be a species that needs to be stimulated by moving prey so to keep them actively hunting.
Juveniles grew quite fast from the constant stimuli of food that they were never allowed to burrow, and they were never over handling. Within 7–8 months of age all Nephrurus Laevissimus were full grown and even as adults they were still never allowed to burrow, except when gravid females were to lay, at which the substrate depth was increased to only 10–12cm, with some females preferring to lay in the shallow end which had a depth of only 5–6 cm. After laying all females were transferred back to the same enclosure styles except only on a 1cm depth of the substrate.
All 22 specimens that hatched out and grew vigorously to over 12 months of age are all still going strong with not a single death to date. Many of these juveniles have gone to new homes with the similar requirements they were accustomed to after hatching.
I stand by the fact that I believe if they are not accustomed to anything different then how do they know what they should or should not be stressed about.
However, they are a very finicky species when compared to other members of Nephrurus and would advise only those individuals who have had experience with geckos in the past to consider them as a new addition to their collection. They are not a first gecko species.
All views outlined above regarding Nephrurus Laevissimus are based on my experiences with this species and should not be understood as a contradiction to other breeders techniques.