Wheeler's knob-tailed gecko

About the species

Nephrurus wheeleri belongs to the knob-tailed geckos, whose short tail ends in a small, round knob. What the knob is used for is not known for certain, but it gives the animal a very distinctive appearance. The body is short and compact, with a large head and big eyes, and the animal looks a little like a small toad. The skin is rough, and the base colour ranges from salmon and rusty brown to dark brown, with broad, pale bands across the back and tail.

The species was described by Arthur Loveridge in 1932 and is named after the American ant researcher William Morton Wheeler. The northern form was long regarded as a subspecies, Nephrurus wheeleri cinctus, but in 2020 it was split off as a separate species, Nephrurus cinctus. This page deals with the southern form, Nephrurus wheeleri in the strict sense.

The split matters for anyone reading further. Older care guides and breeding reports use the old name for both forms, and a large share of the animals in the trade and of the best-documented breeding, including at Perth Zoo, concerns N. cinctus. Several of the figures here are therefore borrowed from the northern sister species, and this is stated in the individual sections. Always check which species a breeder is actually selling.

Adults are small, about 8-10 cm from snout to vent, and the tail is short and broad. There are no reliable weight figures. Lifespan is not documented for the species either, but knob-tailed geckos often live for more than 10 years in captivity, and 10-15 years is an estimate based on its relatives.

The animal is quiet and calm and rarely becomes aggressive. It is mostly an animal to watch, and it is best seen in the evening, when it goes hunting for insects.

Care

The enclosure

An adult can be kept in an enclosure of about 60 × 45 × 30 cm (length × width × height). Height matters little for a ground-dwelling species; floor area does. Many breeders use plastic boxes in racks for breeding, but a somewhat larger, furnished enclosure gives a better chance of seeing the animal's natural behaviour. Juveniles are kept separately in small boxes.

The substrate is fine sand, preferably mixed with a little clay, so that hides and burrows hold their shape. Provide several dark hides with a single opening, for example of cork, and one that is kept damp with sand or sphagnum. Rocks and heavy decor must stand directly on the floor of the enclosure, not on top of the sand, so that the animal is not crushed when it digs. The lid must fit tightly but allow good ventilation.

Males must not be kept together, and most keepers settle for one animal per enclosure. At Perth Zoo, males and females of N. cinctus were kept together in enclosures of 88 × 55 × 60 cm with many hides, but this is an exception.

Temperature

The species needs a clear difference between a warm end and a cool end. Keep the background at 22-27 °C by day and a warm spot in one end at 30-35 °C. At night the temperature may drop to 15-22 °C. The figures are based on Perth Zoo's experience with N. cinctus: in summer 19-26 °C in the air and 31-35 °C at the warm spot, in winter 15-22 °C and 24-28 °C at the warm spot.

Heat from below with a heat mat under one end, controlled by a thermostat, and measure with a digital thermometer at floor level. Many keepers believe that strong light and heat from above stress this nocturnal animal. In winter the temperature can be lowered and the days shortened, so that the animal gets a light winter rest. This is the best way to trigger breeding.

Humidity and water

The species comes from dry regions and must be kept dry, at a humidity of 30-40 %. Mist once or twice a week, no more, and make sure the ventilation is good enough that surfaces are dry again after a few hours. Constant moisture causes skin problems and fungus.

However, there must always be one humid hide with slightly damp sand. This is where the animal lies when it is about to shed, and if the hide is missing, remnants of skin easily stick. Mist the top of the hide now and then too, so that the moisture lasts a couple of days. A shallow dish of fresh water can be left out, but many animals never drink from it.

Lighting and UVB

The species is nocturnal and does not need bright light. Some keepers advise against lamps from above because they stress the animal, while others recommend a low-output UVB light, at most corresponding to Ferguson zone 1, over part of the enclosure when there are plenty of hides. There is no consensus, so UVB is optional.

If you choose UVB, use a low strength, and make sure the animal can always hide from the light. Day length can be 12-14 hours in the breeding season and shorter in winter. The most important thing is that it is dark at night.

Feeding

The species lives exclusively on insects and other small arthropods. Offer crickets or small roaches as the staple and now and then soldier fly larvae, mealworms or waxworms as a treat. Juveniles should have insects of about 6 mm, adults about 12 mm. Most keepers feed juveniles daily and adults three to five times a week.

Dust the insects lightly with calcium, and give calcium with D3 and a multivitamin about once a week. There are no figures for food requirements, so adjust according to the animal's condition. A plump tail base shows that the animal is getting enough, but it should not become fat either.

Behaviour and handling

The animal is calm and tolerates brief handling, but it rarely becomes as tame as a leopard gecko, and too much handling stresses it. Keep sessions short and close to the floor, and do not pick it up during the day, when it sleeps.

A male and a female can be kept together, but males must be kept apart, because they fight. Otherwise the safest option is to keep the animals singly. The tail can be dropped when the animal is frightened, and a new tail often looks different, so never grab it. The animal may also close the entrance to its hide with sand, and this is entirely normal behaviour.

Breeding

Sexual maturity and sexing

Males can be recognised by a distinct bulge at the base of the tail, where the hemipenal pouches sit, and they are often smaller and slimmer than the females. There are no reliable figures for age or weight at sexual maturity, so the field is left empty in the fact box. Wait to breed a female until she is fully grown and in good condition.

Mating

Breeding is triggered by a light winter rest with lower temperatures and shorter days, followed by longer and warmer days in spring and summer. Perth Zoo kept N. cinctus at 15-22 °C in winter and 19-26 °C in summer. Put the female with the male in a spacious enclosure with many hides, and separate them if any unrest arises. The mating itself is only sparsely described for the species.

Egg-laying and clutches

The female lays two eggs at a time and does so several times during the season. The figures come from the northern sister species: at Perth Zoo, four females of N. cinctus laid a total of 40 clutches over four seasons, corresponding to 2-6 clutches per female per year, and American breeders report a clutch every 30-40 days.

The eggs are laid down in the sand, so provide a laying box with 2-4 cm of damp sand, or dig carefully for them. Give the female plenty of calcium and insects so that she is not drained.

Incubation

Perth Zoo placed the eggs of N. cinctus in perlite or vermiculite mixed with water 1:1 or 2:1 and incubated them at 29-30 °C. Only one egg failed to hatch. The eggs must lie as they were laid, without being turned, and they must not dry out.

Incubation time is not reliably documented for N. wheeleri. One account mentions about 67 days, and related species hatch after 55-120 days depending on temperature. The 60-90 days in the fact box are therefore an estimate. It has not been investigated whether temperature determines sex.

Rearing the young

Rearing of young is only sparsely described. Keep each juvenile separately in a small box with fine sand, a small hide and a slightly damp corner at the same temperature as the adults. Offer small insects of about 6 mm dusted with calcium every day, and weigh the young regularly so that you can see that they are growing.

Health and common mistakes

Little is documented about diseases in the species, so the advice is based on common practice for desert geckos:

• Too much moisture, which causes fungus and skin problems. Keep the enclosure dry with one humid hide.
• Remnants of skin on the toes and tail tip, if the humid hide is missing.
• Too little calcium, especially in young animals and egg-laying females. Dust the insects.
• Stress from strong light or too much handling, which can cause loss of appetite.
• Dropped tails after fright or fighting.

A healthy animal has clear eyes, a plump tail and is active at night. See a vet with reptile experience if the animal loses weight, does not eat for several weeks or seems limp.