Breeding Crested Geckos

The short version

• Breed females only at 40 grams or more and at least 18 months old; males at 30–35 grams [16][17].
• Two eggs per clutch, about every 4–5 weeks, for around 6–8 clutches a season [16][17][18].
• Eggs hatch at room temperature, 65–78°F (18–26°C), in about 60–120 days [16][17][18].
• Temperature does not reliably set the sex of the babies [19].
• Calcium loss is the biggest risk to a breeding female. Give her a winter rest every year [17][18].
• Plan for about 10 babies per female per year, each needing its own space for months.

Crested geckos are one of the easiest lizards to breed. No incubator is strictly required, pairs will breed on their own at room temperature, and a healthy female lays small clutches on a steady schedule for most of the year. The hard part is not getting eggs. It is keeping the female in good condition, not over-breeding her, and finding good homes for 10 or more babies per female each year. Read the Genetics and morphs chapter before pairing any geckos with named morphs.

Sexing

Crested geckos are sexed by looking at the underside of the tail, just behind the vent.

• Hemipenal bulge. Males develop a clear, paired bulge at the base of the tail; females stay flat [15]. This bulge usually becomes visible at about 18–25 grams, and sex cannot be confirmed until it develops (or does not) [15]. One hobby guide says differences may show at 8–10 months, with reliable sexing at about 12–14 months [18]. Fast-growing geckos can reach that weight sooner, so weight is a better guide than age.
• Pre-anal pores. Males also have a row of pores on the scales in front of the vent. Some breeders sex earlier by looking for these pores with a jeweler's loupe, but the method is not always accurate [15]. Females can show small pits that look like pores under magnification, often called "false pores," which is why pore-sexing young geckos is unreliable.
• Skin type matters. One breeder reported that very fine-skinned Super Cappuccino geckos were hard to pore-sex, and some males were mistaken for females until 8–9 grams [21].

We recommend treating any young crested gecko as "unsexed" until the bulge is obvious. Mis-sexing is one of the most common disappointments for new breeders.

Maturity and minimum breeding size

Published breeder guidance agrees that weight matters more than age, and that females should be heavier than many people expect.

We recommend females at 40 grams and at least 18 months old, and males at 30–35 grams. A 35-gram female can physically lay eggs, but every source that gives a firm minimum puts it at or near 40 grams [16][17]. A female bred too small tends to stop growing and use up calcium she does not have (see "Protecting the female's calcium" below).

Pairs should be similar in size and outwardly healthy [17]. Keepers report that a big size gap leads to more stress and injury, though this is keeper experience, not proven. Keep a log, and weigh breeders every two weeks during the season [18].

Pairing and group sizes

• Standard setups. One male with one female, or one male with two females, per enclosure is the norm [17]. You can simply place an adult male and female together. Mating may happen within hours or days. Because females store sperm, the pair does not need to stay together all season [16]. Some keepers leave the male in anyway and remove him only if he harasses the female.
• Enclosure size. A pair needs at least an 18×18×24 in (46×46×61 cm) enclosure. A trio or larger group needs something very large and very tall. Larger enclosures also mean less tail loss from chasing and nipping [17].
• Never two males. Males fight, especially with females present [2].
• Sperm storage. Females store sperm for a couple of months after mating [16], so a female can keep laying fertile eggs well after the male is gone. An adult female from another keeper may also lay fertile eggs, even if she was never paired with your male.
• Watch for trouble. Bite marks on the female's crests or sides, weight loss, or a female hiding all day while the male hovers all mean it is time to separate them and let her recover.

Breeding season and the winter rest

Crested geckos do not need a formal brumation, but breeding females do need a break.

Natural rhythm. The breeding cycle runs about 8–9 months, from spring through fall [16]. In the Northern Hemisphere, interest usually drops off from about late October to mid-March [18].

Why a rest matters. A female kept warm with a male year-round may keep laying with no break. Breeders report that this is how females are lost to calcium crash and exhaustion.

How to give the rest (October or November to February or March, 3–4 months):

• Separate the male from the female or females.
• Let the room cool. One hobby guide recommends winter days of 70–72°F (21–22°C) and nights of 63–65°F (17–18°C), with daylight cut to about 11 hours, compared with 13–14 hours in summer [18]. Crested geckos tolerate winter nights in the 60s°F [2].
• Keep feeding. The rest is a chance to rebuild weight and calcium, not a fast.
• Warm back up and lengthen the light in mid-to-late March, then put the male back in [18].

In a cold-winter home, a spare room with the heat turned down often does the job. Do not let the enclosure stay below the low 60s°F (about 16°C) for long.

Egg laying

• Clutch size. Two eggs per clutch is the rule. Single-egg clutches happen, especially at the start and end of the season [16][17][18].
• How often. Sources give a clutch every 30–45 days [16], about once a month [17], or every 20–30 days [18]. Plan on roughly every 4–5 weeks.
• Clutches per season. A healthy female lays about 6–7 clutches a year over 5–7 months, and pushing past 7–8 is not advised [18]. An 8–9 month season at 30–45 day intervals works out to a similar 6–9 clutches [16]. Ten clutches is what happens to a female kept warm too long, and it is not a goal.
• Checking fertility. Shine a small light through the egg ("candling"). A red ring of blood vessels means a developing embryo; yellow or misshapen eggs are usually infertile [17]. The first clutches of a season are often infertile ("slugs"), even from proven females.
• Signs she is gravid. You can often see or feel the eggs as two lumps through her belly skin. Females usually lose a little belly weight after laying [17]. Check lay boxes daily during the season [17].

The lay box

A female without a good place to lay may hold her eggs, dig frantically, or drop them somewhere they dry out.

• Container: a plastic tub about 8×5×5 in (20×13×13 cm) with an entry hole, filled about 4 in (10 cm) deep with damp sphagnum moss [16]. Another breeder uses a few inches of slightly damp coconut fiber and fir bark, roughly half and half [17]. Either works; eggs are easier to spot in moss.
• Moisture: damp, not wet. Do not spray misters into the lay box. Soaked substrate can stop a female from laying or kill the eggs [17].
• Placement: on the enclosure floor, partly hidden by plants.
• Bioactive enclosures: females will lay directly in deep substrate. Check corners and under cork every few days, or you may find hatchlings instead of eggs.
• Mark the eggs with a soft pencil dot on the top before you move them, and keep that side up [17]. Do not turn them.

Incubation

Setup

• Shoebox method: a plastic shoebox two-thirds full of moist incubation medium (such as vermiculite, perlite or a commercial hatching substrate), five to eight 1/8 in (3 mm) air holes in the lid, eggs buried about 1/4 in (6 mm) deep, kept in a cool, dark place [16].
• Deli cup method: 16 oz (475 ml) deli cups half-filled with medium, eggs set about three-quarters of the way in, humidity around 80%, and the lid opened about once a week for fresh air [17].
• One breeder reports hatch rates just over 10% better on a commercial hatching medium than on vermiculite [17]. That is one breeder's figure, not a controlled study.

Temperature and time

This is the species' big advantage: room temperature works [16].

Working range: 65–78°F (18–26°C), and expect 60–120 days or more. Cooler is slower, and that is fine. Many breeders deliberately incubate cool because they believe longer incubation produces larger, stronger hatchlings [19]. This is breeder experience, not proven.

Do not put crested gecko eggs in an incubator set for leopard geckos or ball pythons at 82–88°F (28–31°C). Adults need a cooler room once temperatures pass 87°F (31°C) [2], and breeders consider eggs even less heat-tolerant. If you use an incubator, choose a digital or pulse-proportional thermostat; mechanical ones swing too much [17]. Temperature swings during incubation can kill embryos [18].

Does temperature set the sex?

Not reliably. Hobby sites repeat a rule of thumb that the first two weeks at 80–84°F (27–29°C) favor males and 68–73°F (20–23°C) favor females [18]. In a recent community discussion, experienced breeders described any effect as slight at best (roughly a 55/45 lean), reported mixed sexes from cool clutches, and said there has never been meaningful evidence for it in this species [19]. No peer-reviewed study on temperature and sex in crested geckos has been published.

We recommend incubating for healthy babies (cool and steady), not for a particular sex.

Hatching

Hatchlings slit the shell ("pip") and may rest inside the egg for up to 24 hours while they absorb the last of the yolk [16]. Leave them alone. Keep them in the incubation box until their first shed, usually 12–24 hours after hatching, and make sure the shed comes off completely [16][17].

Hatchling care and first feeds

Housing. Keep it small and simple: a small plastic pet carrier, a 6-quart tub, or a 5 gallon tank at most, with a paper towel floor, one small plant and a vine or piece of cork [16][17][18]. House hatchlings one per tub or in small groups of the same size, and separate any that bully or outgrow the others [18]. Never house hatchlings with adults, especially males [17]. Keep them on paper towel, with no loose substrate, until about 4–5 months old to avoid impaction [17].

Humidity. Mist twice a day [16][17]. Most hatchlings drink droplets off the walls and leaves after misting; a shallow jar lid of water is optional [16]. Add a small moist hide: a container with an entry hole and damp sphagnum moss [16]. Shedding problems in babies are almost always a humidity problem.

First feeds. Expect a fast of a few days. The yolk carries them, and most will not eat for the first 3–4 days [18]; some sources say 2–3 days [20]. Offer food from day one anyway, so it is there when they start looking.

• A complete powdered gecko diet mixed to a paste in a bottle cap or a 1.5 oz deli cup lid, replaced every 24–48 hours [17][20]. One breeder feeds a dime- to nickel-sized blob every other day [17].
• Tiny insects such as pinhead crickets or fruit flies, nothing over 1/4 in (6 mm), once or twice a week, lightly dusted [18][20].
• No fruit purees until they are a few months old [18].

Weight. Weigh weekly on a gram scale. Early gains run about 1–2 grams a month [20]. A hatchling that loses weight for two weeks in a row needs a closer look for stuck shed on the toes, bullying or dehydration.

Handling. Give new hatchlings several days to settle, ideally a couple of weeks, before handling [17].

Protecting the female's calcium

Egg production pulls calcium out of a female faster than almost any diet can replace it. Even on a supplemented diet, egg-laying uses up much of her calcium storage [18]. This is the single biggest health risk in crested gecko breeding.

The calcium sacs. Crested geckos store calcium in a pair of sacs on the roof of the mouth, toward the back, that look like two whitish lumps. Gently opening the mouth (a soft fingertip at the snout, never forced) lets you see them. Full, plump white sacs mean good reserves; small, flat or grey sacs mean she is running low. Check a breeding female's sacs at least a couple of times each season, and if they shrink a lot or start out small, do not breed her until they look healthy [17]. How to read the sacs is breeder guidance; there is no veterinary reference specific to calcium in breeding crested geckos.

Warning signs of a calcium crash: trembling or twitching limbs, a rubbery or kinked jaw, weak grip, a wavy spine or tail, tiredness, or stopping laying mid-season. These are signs of low calcium and metabolic bone disease and need a vet visit, not a wait-and-see. Remove her from the male right away.

Prevention:

• Feed a complete powdered gecko diet year-round as the staple, not fruit [17][18].
• Dust feeder insects with calcium [2][18]. The powdered diet already contains D3, so use calcium with D3 only if you do not use UVB, and never stack several D3 products; too much D3 can be toxic.
• Many breeders keep a small dish of plain calcium (no D3) in the enclosure during the season so she can help herself. This is breeder experience, not proven.
• Weigh every two weeks. A laying female who keeps losing weight is being pushed too hard [18].
• Give her the 3–4 month winter rest.
• Do not breed a female under 40 grams.

Egg-binding can follow calcium shortage or a missing lay site. A visibly gravid female who has not laid in 6–8 weeks, is straining, or stops eating needs a vet.

Retirement

Crested geckos live 15–20 years with good care [2]. Healthy females can breed to about 10 years old, but 7–8 is more typical, and clutch counts drop with age [18]. A sensible plan:

• First season at 18–24 months and 40 grams or more.
• Full breeding seasons from about age 2 to age 7–8.
• Retire a female early if she loses condition two seasons in a row, has had a calcium crash, or lays mostly infertile eggs.
• A retired female makes an excellent pet. If you rehome her, tell the new owner she may lay a clutch or two from stored sperm.

Males can breed much longer than females but still benefit from the winter rest.

How many babies to expect

These figures are worked out from two eggs per clutch every 30–45 days over a 5–9 month season [16][17][18], with 6–7 clutches as normal and 7–8 as the ceiling [18]. The 75% hatch rate is a planning estimate (breeder experience, not proven). First-season females and the first clutches of any season usually do worse.

What this means for you. One pair, bred responsibly, gives about 10 babies a year. Each needs its own tub and 3–4 months of care before it is ready for a new home. Breeders commonly wait until a baby weighs at least 5 grams and is eating well on its own; this is a hobby rule of thumb. Three breeding females can mean 30 or more babies, and 30 or more tubs, by late summer. Plan space, food and good homes before you add more breeders.

Breeding checklist

1. Female 40 grams or more and at least 18 months old; male 30–35 grams; both parasite-free and in good body condition.
2. Check her calcium sacs before pairing and twice more during the season.
3. One male with one or two females in an 18×18×24 in (46×46×61 cm) or larger enclosure, with the lay box in place before the male goes in.
4. Check the lay box daily. Mark the eggs and move them to deli cups of damp incubation medium.
5. Incubate at 65–78°F (18–26°C) in a closet or on a shelf. Expect 60–120 days, and open the lids weekly.
6. Leave hatchlings in the cup until the first shed, then house them on paper towel. Offer food from day one, and expect 3–4 days before they eat.
7. Remove the male in October or November and give the female a 3–4 month cool rest. Keep feeding her well.
8. Weigh every gecko every two weeks and write it down.
9. Never pair Lilly White with Lilly White, or Cappuccino with Cappuccino. See the Genetics and morphs chapter.

Wash your hands with soap and water after touching your crested geckos, their eggs, their enclosures or anything in them. The CDC says children under 5 should not touch reptiles, and reptiles are not recommended for homes with children under 5, adults 65 and older, or people with weakened immune systems [6].