Lizards are fascinating creatures that have been around for millions of years. If you’ve ever wondered how lizard eggs work and develop, you’ve come to the right place!

If you’re short on time, here’s a quick answer to your question: Lizard eggs are soft and leathery, unlike bird eggs which have hard shells. The eggs are often laid in warm, humid places to incubate. After laying the eggs, the female lizard provides no further care.

In this comprehensive guide, we will cover all the details about lizard egg biology, reproduction, incubation, hatching, and care.

Lizard Reproduction and Egg Development

How Lizards Reproduce

Lizards reproduce sexually, with both males and females needed for breeding. The male lizard uses his hemipenes to transfer sperm to the female’s cloaca during mating. Once the eggs are fertilized internally, the female then lays the eggs in a nest or burrow she has prepared.

Most lizard species are oviparous, meaning they lay eggs. However, some species like skinks and gila monsters are ovoviviparous – they give birth to live young. The gestation period varies by species, but can range from 4-12 months before eggs are laid or live babies emerge.

Stages of Egg Development

Once fertilized, the lizard eggs undergo several stages of development before hatching:

  • Cleavage – The single-celled zygote begins rapidly dividing into multiple cells
  • Blastulation – A fluid-filled cavity called a blastocoel forms within the dividing cells
  • Gastrulation – Cells migrate to form 3 distinct cell layers that will become specialized tissues and organs
  • Organogenesis – Organs begin developing in the embryo from the specialized cell layers
  • Growth – The embryo continues growing inside the egg, nourished by the yolk

The length of these developmental stages depends on the species. For example, leopard gecko eggs hatch in 60-90 days, while bearded dragon eggs take 60-75 days on average.

Egg Structure and Composition

Reptile eggs come in a variety of shapes, sizes, and colors depending on the species. But they share some common structural features:

  • Shell – Made of calcium carbonate, the shell protects and supports the developing embryo.
  • Membranes – Inner and outer membranes surround the embryo and yolk.
  • Albumen – Watery proteins that cushion and nourish the embryo.
  • Yolk – Main food source for the growing embryo, contains fats, proteins and nutrients.
  • Chalazae – Twisted strands that anchor the yolk and keep it centered.

The eggshell is porous to allow gas exchange for the embryo to breathe. Its thickness and pliability depend on where the eggs are laid – buried eggs need thicker, harder shells while eggs in humid nests can have softer, more permeable shells.

The yolk size also varies, with more yolk needed to sustain embryos of species with longer incubation periods.

Turtle Spherical shape, leathery flexible shell, lots of yolk
Lizard Oval shape, moderately pliable shell, moderate yolk
Snake Elongated leathery shell, very little yolk

As you can see, lizard eggs are generally oval-shaped with a moderately pliable shell and contain a sufficient but not excessive amount of yolk. The special composition provides protection, optimal gas exchange, and nutrients to support embryonic development in diverse nest environments – allowing lizards to continue thriving on our amazing planet!

How to Incubate Lizard Eggs

Choosing an Incubator

When selecting an incubator for lizard eggs, there are a few key features to consider. Many reptile owners opt for still-air plastic incubators that allow for easy adjustment and monitoring of temperature and humidity levels (example).

Important factors in an incubator include tight temperature and humidity control, sufficient ventilation, and ease of access for checking on the eggs.

An ideal incubator will allow temperature to be maintained within 1° to 2°F of the level needed for the specific lizard species. Tight humidity control, generally within 5%, is also crucial. Some more advanced incubators now come with built-in hydrometers and thermostats to automate these processes.

Setting Up the Incubator

When setting up the incubator, it is key to achieve stable conditions before placing the lizard eggs inside. Recommended steps include:

  • Determining the optimal temperature and humidity levels for the lizard species.
  • Allowing the incubator to run empty for 24 hours, adjusting as needed to achieve suitable levels.
  • Using a separate thermometer/hydrometer to double check readings.
  • Preparing a suitable substrate, like perlite or vermiculite, moistened to proper specifications.

Once the incubator environment is stabilized, the eggs can be gently placed in the prepared substrate, taking care not to shift their orientation. Continued monitoring and minor adjustments may still be needed at first before leaving the eggs to develop.

Maintaining Proper Temperature and Humidity

Consistent temperature and humidity is vital for proper embryonic development and hatching success. For most species, temperatures between 80°F and 90°F are required. Each lizard has specific humidity needs, like 50% for bearded dragons and 80% for chameleons.

Fluctuations beyond a few degrees or percentage points in either direction can negatively impact eggs or even terminate development. So consistent monitoring and adjustments are essential. Some tips include:

  • Checking temperature and humidity twice per day, adjusting as required.
  • Adding water to substrate gently with pipette if humidity drops.
  • Using a secondary thermostat or dimmer switch to fine tune heating elements.
  • Ensuring sufficient water reserves in the incubator system.

With close attention, the optimal incubation environment can be provided, giving young lizards the best chance to develop fully before emerging.

Candling the Eggs

Candling lizard eggs involves shining a bright light through them to observe development and check for viability issues. It should be done sparingly to avoid disturbing the embryos or altering incubation conditions. But brief weekly candling sessions can provide useful insights.

Key things to look for when candling include:

  • A dark mass indicating normal growth – this will increase in size over time.
  • Enlarging blood vessels as oxygen needs rise approaching hatching.
  • Unfertilized eggs appearing yellowish without vessels or embryonic development.

If problems like interrupted vessel growth or odd shapes occur, undesirable incubation factors may be affecting normal development. So candling helps ensure conditions stay on track right up to the exciting moments when the young lizards start breaking out!

Caring for Lizard Eggs and Hatchlings

Protecting the Eggs

Once a female lizard lays a clutch of eggs, it is up to the owner to ensure they are kept safe and healthy while incubating. Ideal incubation temperatures range from 82°F to 88°F depending on species, with humidity around 80%.

The eggs should be placed in a secure container with ventilation holes and a substrate that holds moisture well, such as vermiculite or sphagnum moss. Keep the substrate slightly damp but not soaked. Check regularly that the temperature and humidity levels are in the optimal zone.

Also make sure the eggs are not disturbed, as vibration can harm the developing embryos.

Assisting with Hatching

When lizard eggs are close to hatching after 30-80 days, reduce the humidity slightly to help the baby lizards fully emerge. Never try to manually open an egg, as this can fatally injure the hatchling inside.

Gently brushing an emergent opening with a soft paintbrush can assist the lizard if it is struggling to break out. Their egg tooth, a temporary sharp protuberance on their snout, will fall off a few days after hatching. Avoid handling hatchlings at this stage as they are vulnerable.

Place food such as small crickets or flightless fruit flies close to the eggs so the babies can easily find sustenance after they fully emerge.

Caring for Hatchlings

The tiny hatchlings are extremely fragile for the first few weeks, so leave them undisturbed in the incubation setup until they triple in size. Then they can be moved to room temperature housing with proper heating and UVB lighting.

Start with a basic 10 gallon tank, upgrading once they reach adulthood. Make sure hatchlings feel secure by providing hiding spots. Feed daily with size-appropriate live insects and calcium powder sprinkled on them. Light misting provides necessary hydration if bowls are not utilized.

As they grow, adjust to larger feeder insects and vegetables. Proper care in these early days ensures your amazing baby lizards will thrive for years to come! For more tips, check out the detailed guides at


We’ve covered everything you need to know about lizard egg biology, incubation, hatching, and care. Proper incubation is crucial for the eggs to develop healthily. Once hatched, the tiny lizards require attentive care as they grow.

We hope this guide gave you a comprehensive understanding of the amazing process of lizard reproduction and development!

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