Have you ever wondered how lizards have babies? The answer is actually more complicated and curious than you might think!
In this guide we explain the most common forms of lizard reproduction and how to identify lizard eggs.
4 Ways That Lizards Reproduce
Lizards are pretty unique animals when it comes to reproduction. Depending on the lizard species, they can give birth to live young, lay eggs, or even combine the two processes where their eggs “hatch” inside their bodies, making it appear as if they are giving birth to live young.
Some lizards are even able to decide which method to use depending on the suitability of their environment! So how exactly do lizards give live birth and lay eggs, read on to find out.
Oviparity (egg-laying)
Oviparity means an animal’s eggs are fertilized internally and then develop inside the female’s body to a certain point. Once they have reached a specific point, the female lizard will dig a nest, lay her eggs inside, and leave them to develop on their own.
The time it takes for lizard eggs to develop until they are fully mature and ready to hatch can vary significantly. They can take anywhere from just a few weeks to hatch all the way up to several months or even a year; it all depends on the species!
Most lizards lay eggs (scientists estimate up to 90%). Examples of oviparous species include asian water dragons, bearded dragons, geckos, iguanas, chelonians and crocodilians.
Viviparity (live-birth)
About 10% of lizards are viviparous, in other words they give birth to live young.
Viviparity can be an advantage for reptiles as it protects the babies from danger for longer, but it also takes quite a toll physically on the female lizard.
Viviparity is not common in reptiles because they are not altricial animals. Altricial animals are born without being fully developed and must rely on their parents until they are developed enough to be truly independent.
The majority of viviparous lizards belong to the skink family, Scincidae.
How Do Lizards Give Birth?
During the viviparous process, the growing lizard embryo absorbs nutrients directly from their mother’s body via the placenta. Fertilization and the full duration of embryonic development happen within the mother’s body, and she will give live birth to fully-formed baby lizards.
Essentially, this means the lizards are born fully developed without the aid of an external egg or any kind of shell!
Ovoviviparity (combination of egg laying and live birth)
Some female lizards develop their babies’ embryos inside of a shell inside of their bodies until they are ready to hatch! This is a combination of oviparity and viviparity.
This often happens in species that live where environmental conditions are not optimal for egg development. Either the temperatures are too cold or the humidity levels are too low or too high and would either dry out or drown the egg.
When the eggs are ready to hatch, the mother’s body will have contraction-like muscle spasms to help break the eggs open (while the eggs are still inside her body!) and then push the baby lizards out.
After the lizard babies have all been ‘born,’ the broken eggshells and any unhatched eggs (also known as “slugs”) will be passed, too. Fortunately, lizard eggs’ shells are soft, flexible, and leathery rather than being firm and rigid like those of birds.
Due to the size of the eggs relative to the size of the mother’s body, these clutches are very small and often only consist of one or two baby lizards being born. Sungazer lizards are an example of ovoviviparous lizards.
Bimodal Reproduction
Bimodal reproduction is where different lizards within the same single species will lay eggs and give birth to live young.
Zootoca vivipara and Saiphos equalis, are an example of a species with bimodal reproduction. Depending on the environment and quality of their surroundings, these lizards can either lay eggs or give birth to live young!
Amazingly, scientists recently discovered that the bimodally reproductive three-toed skink can do both but within the same pregnancy. The Australian lizard was recorded laying eggs and then giving birth to a live baby a few weeks later, with all the babies coming from a single pregnancy. It’s the first time that a vertebrate animal has been discovered to do that so it was pretty exciting news!
How Many Eggs Does a Lizard Lay?
The number of eggs in each clutch also varies and is largely dependent on the size of the lizard. The average clutch is two to four eggs per clutch. Anoles lay just one egg per breeding season, while asian water lizards lay an average of 9 eggs.
Large lizards will lay large clutches. Green iguanas, for example, can lay over 50 eggs in a single egg clutch!
The number of eggs a lizard lays usually increases as the lizard gets older, so younger lizards will usually lay smaller clutches.
What Do Lizard Eggs Look Like?
Lizard eggs are soft and leathery when they are laid. Most species’ eggs will stay soft and slightly pliable throughout their development. This is because they are semi-permeable, which means water can get in and out of the egg through the shell.
The eggshell will grow with the lizard as the embryo grows and becomes fully formed. However, some lizard eggs become hard if there is a danger of losing too much moisture due to poor habitat conditions.
Lizard eggs are oblong in shape and are usually an off-white color. They are also often incredibly tiny! Lizard eggs can be as small as 0.39 inches in length! Depending on the species, you might mistake its egg for an insect’s egg or a pebble!
Where Do Lizards Lay Their Eggs?
Female lizards start to look for safe nesting places to lay their eggs soon after mating.
Lizards lay their eggs in very sheltered areas like under piles of wood, in drain pipes, in rock crevices, under sheds or steps, in long grass, in tree hollows or under dense shrubs where there is ample moisture.
The ideal nesting place will be quiet, dark, moist, and away from predators to boost the chance of survivability for their young.
Once a suitable nesting place is spotted, the female will dig a shallow nest for her eggs and lay them. In some instances, lizards who do not have access to this type of nesting site will lay their eggs in a rock crevice to protect them from the elements.
This means you could find lizard eggs in your backyard, on your school grounds, or out on a hike! It is always best to leave these eggs alone and not to disturb them, as you run the risk of detaching the embryo inside the egg, which will cause it to suffocate and die. Lizard eggs are very fragile due to their small size and soft, flexible shells.
Clutch sizes vary significantly amongst different kinds of lizards. A lizard’s age can also influence the size of her clutch. Young female lizards do not know the best nesting sites and do not lay many eggs in their first couple of breeding seasons. However, older females are more experienced and thus more inclined to lay larger clutches because they have usually found optimal nesting sites.
Lizards that give birth to eggs do so in similar places that snakes and turtles do. That’s why it’s important to know the difference between the eggs that you may find in your garden.
How Do Lizards Mate?
The average lizard procreates during a mating season. This is typically between spring to August although it can vary by lizard species.
Usually, the mating ritual will involve the male trying to attract a female whether that’s through dancing, bobbing their head, releasing a particular scent or displaying attractive colors in the case of chameleons. The female will choose the male which she believes will give her the best chance of producing healthy babies.
Once mating is complete, the female lizard will look for somewhere to lay her eggs (if she’s oviparous). The male snake will look for another female to mate with.
Asexual Reproduction
Some lizards can reproduce asexually in a process called parthenogenesis. All females in the Lacerta genus as well as all female whiptail lizards are able to produce eggs that contain all the DNA they need and do not need to be fertilized by a male.
Eggs produced in this way result in baby lizards that are direct copies of their mother. Certain gecko species, some spectacled lizards, and lizards belonging to the Teiidae genus are also known to undergo parthenogenesis.
Lizard Reproduction FAQs
Do lizards lay eggs?
Yes, 90% of lizards are oviparous (egg-laying). Lizard species such as skinks, anoles and many geckos are egg laying.
Do lizards give live birth?
Yes, some lizards are viviparous (so they give birth to live young). The European lizard, skink species such as the Schmidt’s Helmet skink and the Jackson’s chameleon are examples of live birthing lizards.
Can female lizards have babies without a male?
Yes, some female lizards can reproduce without a male lizard. Female lizards in the Lacerta genus as well as all female whiptail lizards are able to produce eggs that don’t need to be fertilised by a male lizard. The babies are identical clones of their mothers!
What animals eat lizard eggs?
Lizard eggs are scrumptious snacks for many foraging animals. Foxes, dogs, cats, owls, various other birds of prey, raccoons, opossums, other lizards, and snakes all love to find and eat lizard eggs.
Lizard eggs are high in both fat and
Do lizards’ mothers stay and protect their eggs and babies?
Most lizards are precocial, which means they are born fully developed and ready to face the world. As a result, their mothers do not stick around to raise them or protect them from predators.
Some lizards, however, exhibit a tiny degree of parental care. The parent lizards do not necessarily care for and fend for their young. Rather, the baby lizards are allowed to stay with their parents in a family group for a couple of months. This has been documented with prehensile-tail skinks.
I found eggs in my garden; who do they belong to?
The eggs in your garden could belong to birds, snakes, lizards, tortoises, or turtles!
Bird eggs are pretty easy to identify. They are very brittle, have a hard, calcified shell, and are usually found in a nest. You might find them under a nest if the egg has fallen out of the tree.
Tortoise and turtle eggs will be buried underground and will have a leathery feel to them.
Snake eggs and lizard eggs are the most similar out of all of these. Both types of eggs are oblong and shaped a lot like Tic Tacs. They are very leathery and soft to the touch.However, there are some other key differences, such as size and location.
Have a look at our guide to the differences between snake eggs vs. lizard eggs for more information.
Scurrying Off…
The answer to the question, “How do lizards have babies?” is a surprisingly long, nuanced, and complex one.
Oviparity, viviparity, and ovoviviparity (as well as parthenogenesis) all developed in different species of lizards to suit their natural habitats and lifestyles.
This can make it tricky to breed many species of lizards. Some lizards need ultra-specific care in order for their reproduction to be successful. If you’re interested in breeding your pet lizard, make sure you do plenty of research and get advice from a reptile vet.
