Northern Blue Tongue Skink Breeding

Northern blue tongue skink breeding depends on four steps done in order. Sex a true pair, cycle both animals through a cooler rest period, introduce them for a short supervised window, then prepare for live birth rather than an egg clutch.

The northern subspecies, Tiliqua scincoides intermedia, is ovoviviparous. The female carries developing young internally and delivers fully formed babies.

This guide covers northern blue tongue skink breeding step by step. It moves through sexing, maturity, cooling, introductions, gestation, birth, litter size, and neonate care in order.

Sexing Adult Northern Blue Tongue Skinks

Visual sexing in Tiliqua skinks is unreliable on its own. In the closely related eastern subspecies, San Diego Zoo Global’s fact sheet notes females run slightly longer than males. Adult males also carry a subtly wider head, though the difference is subtle across wild populations.

A husbandry manual for the eastern subspecies from Western Sydney Institute of TAFE agrees. Females are generally longer with larger bodies and narrower heads.

Males show a broad, heavy head. The manual also flags a common myth: belly color, orange for females and blue for males, is not a reliable guide.

A reptile veterinarian can confirm sex more reliably by probing the tail base for hemipenes, or by popping a young animal, standard techniques used across many lizard species. Confirm sex before attempting northern blue tongue skink breeding. Two animals of the same sex will never produce a litter, however long they are conditioned together.

When Northern Blue Tongue Skinks Reach Breeding Age

LafeberVet lists sexual maturity at 2 to 3 years old for the northern subspecies. In the closely related eastern subspecies, San Diego Zoo Global gives a more precise figure of 561 to 590 days, close to 1.5 to 1.6 years, with maturity size ranging 220 to 371 millimeters, measured snout to vent.

Body size matters as much as age. A skink that has not reached its adult weight and length is a poor breeding candidate, even if it has passed the minimum age.

Wait an extra season for a smaller animal to finish growing before starting northern blue tongue skink breeding. This lowers the risk of a difficult birth.

Winter Cooling Before the Breeding Season

Northern blue tongue skinks breed on an annual cycle. That cycle is tied to seasonal change across their native range in Queensland and northwestern Western Australia. Oakland Zoo, reporting on the species as a whole, places the breeding season in spring, from August through November in the Southern Hemisphere, right after the cooler, drier part of the year.

Smithsonian’s National Zoo places northern births in the middle of the Australian summer, around January. Counting back a 3 to 4 month gestation puts mating in the spring, from about September to October, as the dry season ends.

The only published cooling protocol comes from the eastern subspecies. The TAFE husbandry manual cools eastern breeding adults to 13 to 18 degrees Celsius (55 to 64 degrees Fahrenheit) for two months.

It then warms them gradually. That is a temperate lizard’s winter, and it is too cold for a tropical northern.

No authoritative source gives an exact protocol for the northern subspecies. The common keeper standard is a mild version of the eastern one.

Take a few degrees off the basking spot and cool end, and shorten the days, for several weeks before pairing. Never drop temperatures below the skink’s normal cool end range of 70 degrees Fahrenheit, per LafeberVet.

Treat that mild cooling as a keeper convention, not a confirmed species requirement. Stop feeding a few days before the cool period so the gut is empty.

Introducing Pairs and Mating Behavior

Northern blue tongue skinks are solitary by nature. LafeberVet describes the species as very docile toward keepers overall, but notes it must be housed alone. Individuals, including juveniles, will fight savagely with other blue tongue skinks.

• House male and female separately year round. Bring them together only once both are confirmed healthy, at breeding weight, and past the cooling period.
• Supervise every introduction in person. Separate the pair at the first sign of biting, tail chasing, or repeated lunging.
• Limit cohabitation to the mating window itself. Return each animal to its own enclosure afterward rather than housing a pair long term.

The TAFE manual describes courtship in the eastern subspecies. A receptive female wiggles her tail.

The male approaches, nudges her side, then grips her neck in his jaws to hold her. Minor scuffing near the neck and shoulders is common afterward.

Open wounds, missing digits, or a lethargic animal call for immediate separation and a veterinary check. This introduction stage is the riskiest moment in northern blue tongue skink breeding.

Gestation and Signs of Pregnancy

Once mating succeeds, gestation runs roughly 3 to 4 months, per Oakland Zoo’s species level account. San Diego Zoo Global’s data on the closely related eastern subspecies matches this range closely. The TAFE manual for the eastern puts it at about 100 days.

A gravid female typically shows a visibly rounded, heavier midsection in the final weeks. She often eats less and basks more, working to keep her body temperature elevated to support the developing litter.

Raise the basking temperature slightly during this period. Keep shallow water available at all times. Provide a secluded, well hidden spot away from the busiest area of the enclosure for the final weeks, since a female close to giving birth becomes more defensive.

Litter Size: Sources Differ

Reported litter sizes for Tiliqua scincoides vary by population and source. The figures below should be read as overlapping ranges, not a single fixed number.

Litter size tends to rise with the female’s age and body size across sources that tracked this factor. A first time breeder is more likely to land on the smaller end of these ranges.

An older, larger, well conditioned female is more likely to produce a bigger litter. That pattern shows up across northern blue tongue skink breeding records generally.

Live Birth: What to Expect

Blue tongue skinks give live birth. No eggs are laid and no incubator is needed at any stage. Smithsonian’s National Zoo confirms this directly for the northern subspecies, describing it as live bearing with no eggs produced.

San Diego Zoo Global’s account of birth in the eastern subspecies notes that females give birth during daylight hours after warming their bodies, with the full litter delivered over roughly 1.5 to 8 hours. Each neonate emerges inside a thin membrane and breaks free within moments.

Leave the female undisturbed during and right after birth. Remove any stillborn young or unbroken membranes once she has settled.

Offer her food again once she shows interest, typically within a day or two. This marks the final stage of northern blue tongue skink breeding for that season.

Neonate Size and First Care

Smithsonian’s National Zoo gives newborn northern blue tongue skinks an average length of about 5 inches, close to 127 millimeters, and a starting weight around half an ounce. In the eastern subspecies, San Diego Zoo Global measured neonates at 90 to 130 millimeters snout to vent and 8.4 to 20.7 grams at birth. The TAFE manual gives eastern newborns as 130 to 140 millimeters total length and 10 to 20 grams.

Set up each neonate in its own small enclosure with the same basic requirements as an adult, scaled down. It needs a warm end, a cooler end, UVB lighting, and secure hides at both ends. Add shallow water a small skink cannot drown in.

Newborns need no help feeding. The TAFE manual calls eastern neonates precocious and weaned the minute they are born. It feeds them five times a week on the adult diet, finely mashed.

LafeberVet notes that juveniles of the northern subspecies eat more prey items than adults. Offer suitably sized insects and greens more often than the adult schedule.

Growth is fast when food is plentiful. Smithsonian’s National Zoo reports that northern blue tongue skink neonates can reach adult size in under a year. San Diego Zoo Global notes the eastern subspecies gains its brighter, glossier adult coloration by around 8 to 9 months old.

Separating Neonates

Northern blue tongue skinks must be housed one per enclosure. That rule applies to babies just as strictly as it does to adults. LafeberVet notes the subspecies fights savagely with conspecifics even as juveniles, and the TAFE manual reports that eastern neonates inflict wounds on each other when housed together.

Separate the litter into individual enclosures once each neonate is feeding and moving normally, generally within the first week. Watch early for tail nips, missing toes, or one animal avoiding another. These are early signs that group housing is causing harm.

Keep records of birth date, starting weight, and feeding response for each neonate. Uneven growth within a litter is common. An animal that lags noticeably behind its siblings may need a veterinary check.

For general day to day care once neonates are established, see the northern blue tongue skink care guide.

Related Reading

The northern blue tongue skink is one subspecies within a wider group. Most of the precise reproductive numbers above come from its closely related eastern blue tongue skink, which has been studied far more closely. Treat eastern figures as a guide, not a guarantee, for a northern pair.

A female in breeding condition needs to be well fed but not fat. The northern blue tongue skink diet guide covers the greens heavy ratio and weekly supplement schedule that support a healthy litter.

The fighting described above is the main risk in the whole process. The behavior guide explains the warning signals to watch for during introductions.

The main northern blue tongue skink overview covers identification and general care. Its lifespan in human care is about 15 years, per Smithsonian’s National Zoo, so a female bred at 3 has many seasons ahead of her.

Frequently Asked Questions

Do northern blue tongue skinks lay eggs?

No. They are ovoviviparous and give live birth, with young developing inside the female and emerging already mobile. No incubator or nest box is needed at any point.

How can you tell a male northern blue tongue skink from a female?

Visual differences are subtle, even in the closely related eastern subspecies. Females run slightly longer and males carry a marginally wider head. A veterinarian confirming sex by probing or popping is more reliable than judging by appearance.

What age do northern blue tongue skinks start breeding?

LafeberVet lists sexual maturity at 2 to 3 years old for this subspecies. Breeding readiness also depends on the animal reaching its adult body size, not just its age.

How many babies do northern blue tongue skinks have?

Reports vary by source. Smithsonian’s National Zoo gives 6 to 12 typical for the northern subspecies, with a maximum near 25. Species level and eastern subspecies sources report averages closer to 10 to 15.

How long is gestation for a northern blue tongue skink?

Species level data from Oakland Zoo places gestation at roughly 3 to 4 months from successful mating to birth. San Diego Zoo Global’s data on the closely related eastern subspecies matches this range.

Do northern blue tongue skink babies need to be separated?

Yes. This species fights with conspecifics even as juveniles. Littermates should move into individual enclosures within about the first week after birth.