How Do Lizards Mate?

Written by Rebecca Mathews
Published: March 22, 2023
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Lizard reproduction is so different from the mammals we are more familiar with that it might seem strange, even frightening! However, nature knows what it is doing, and in the case of lizards, they are an extremely successful species, so they must be doing something right! So, let’s find out a bit more about lizard reproduction and answer the question “how do lizards mate” because it’s not a straightforward answer.

What Is a Lizard?

Before we look at lizard mating and reproduction in more depth, it’s worth finding out exactly what a lizard is because this will shed some light on their mating behavior.

Lizards are squamate reptiles, and there are more than 7,000 species ranging from tiny half an inch chameleons to massive ten feet long Komodo dragons. Most have four legs (although some, like the Western Eurasian Anguis fragilis, have lost their legs through evolution) and are usually carnivores. So, for example, small lizards eat insects, whereas Komodo dragons prey on huge water buffalo.

Some lizards, like Komodo dragons and Gila monsters, are venomous, but smaller lizards, like skinks, tend to rely on camouflage and fast speed to keep safe. Some, like the five-lined skink, drop their tail when caught, so the predator is left holding a few inches of the tail tip as the skink makes a speedy escape.

These incredible reptiles exist on every continent except Antarctica; many make excellent pets.

Komodo Dragon Stretching

Komodo dragons are the biggest lizards in the world.

©GUDKOV ANDREY/Shutterstock.com

How Do Lizards Mate?

Male lizards have not one but two penises on the underside of their bodies, so they are known as hemipenes.

Sperm from the right testicle enters the right hemipenis, and it’s the same for the left side. Hemipenes often have spines, hooks, or knobs which line up with projections in the female cloaca. During mating, males deposit sperm inside a female lizard’s cloaca, fertilizing her eggs.

A cloaca (pronounced “clo–acre”) is an opening that a female lizard’s digestive and genital tracts open into. It’s unfortunately named after the Latin for “sewer”! Birds, amphibians, and reptiles have a cloaca, but mammals do not.

When lizards mate, the male holds the female lizard’s head or neck in his mouth to stop her from running away. Then, when she is receptive (some experts think the male’s grip on her head is an indication of strength and, therefore, superior genes), the male places his tail beneath hers and, at the point of mating, forms a “hammerlock” twisting his body over hers. Then, sperm is placed inside the cloaca.

Often, the pair will remain like this for some time. Mating lizards have been observed remaining in an awkward mating position for ten hours, and experts think it’s due to the hemipenes’ hooks and spines. This makes them vulnerable to predators, so the mating season is dangerous for predated lizards.

If you find lizards in the mating position, don’t interfere or try to move them because it can damage their internal organs. It’s a natural process; just move on!

But wait, because not all lizards mate. Some are asexual and able to produce offspring without a partner. More on that later.

A couple of Carolina Green Anoles mating on brick material.

©iStock.com/Rachel Fleming

How Do Lizards Reproduce?

Most lizards sexually reproduce, which means sperm fertilizes female eggs, and fertilized eggs mature into baby lizards. Fertilization can take place outside their bodies or inside, depending on their species and their environment.

The Egg Layers

Egg-laying female lizards (oviparous) choose a safe, warm spot where eggs can mature without any interaction. Popular spots are beneath vegetation, pits, under logs, and in garden compost bins. Lizard eggs don’t look like hens’ eggs because they are not hard but leathery, much like snake eggs but smaller. A lizard’s egg is usually half to one inch in length.  

Eggs are very vulnerable to predators, which include foxes, snakes, possums, raccoons, and birds.

The amount of laid eggs depends on the species. For example, Anoles lizards lay one, skinks usually two, but both abandon the eggs, which hatch two to four weeks later.

The Live Birthers

Some female lizards give birth to live young and don’t lay eggs.

This is called being viviparous and means the lizard nourishes its young internally. It’s more common in harsh environments and extreme climates and the rarest way for reptiles to reproduce.  

Popular blue-tongued skinks reproduce this way, as does the Eurasian common lizard (Zootoca vivipara), which is named after its ability to birth live young. Live young stay with their parent for a short time to keep safe and improve their chances of survival.

Do Lizards Lay Eggs - Lizard Eggs

Lizard eggs don’t look like hens’ eggs because they are not hard but leathery. A lizard’s egg is usually half to one inch in length.

©Rashid Valitov/Shutterstock.com

But Here’s a Twist!

Some lizards, like the Zootoca vivipara and the three-toed skink, can do both!

While they usually birth live young, they are also capable of laying eggs. Experts think the process is down to the environment. For example, three-toed skinks lay eggs near Sydney, Australia, but live young in northern New South Wales, Australia, where the climate is more extreme.

What Lizard Is Asexual?

Asexual lizards have the ability to produce offspring without mating. There are 20-50 known lizard species capable of this “parthenogenesis” process, and experts think it may be widespread across lizard species.

One such lizard is the New Mexico whiptail lizard (Aspidoscelis neomexicana). Most asexual animals produce clones of themselves, but experts have discovered whiptail lizards actually produce new genetic material by themselves.

In other lizards, like the Caucasian rock lizard, a form of asexual reproduction is implemented. Mating and sperm from a male lizard activate female eggs, but the male’s DNA is not used to create babies.

Lizards really are weird and wonderful creatures!

Asexual lizards have the ability to produce offspring without mating. New Mexican Whiptail lizards can produce new genetic material by themselves.

©iStock.com/nameinfame

Do Lizards Have to Mate to Lay Eggs?

Lizards don’t need to mate to lay eggs, but usually, mating is required to make babies. As a result, unfertilized eggs don’t hatch, and lizard keepers dispose of them.

Common Lizard Mating Behavior

Most lizards that need a sexual partner display mating behaviors when they are ready to mate. Here are some of the most common.

Visual Displays

Instead of fighting, lizards, like the red-headed agama, change their skin color to bright red with a blue tail to ward off other males. The green anole lizard inflates its dewlap skin to epic proportions to ward off competitors and impress females.

One of the most common visual displays is head bobbing and press-ups. These might look comical to us, but female lizards are impressed by the most enthusiastic displays, and competitor male lizards feel intimidated by their strength. In turn, it can avoid physical confrontations that cause injuries. Of course, captive lizards sometimes head bob and employ press-ups to catch their owner’s attention too!

Scent

Some females release a pheromone scent that attracts males from femoral pores on their inner thighs. A desert iguana (Dipsosaurus dorsalis) also emits lipids that attract ultraviolet light and highlight their position to males.

Fighting

Some male lizard species fight for breeding rights, and the defeated male will leave the area soon after the battle. These battles are fierce and capable of leaving life-changing wounds. For example, Komodo dragons are a lizard species that engage in ferocious fighting over females, often vomiting and defecating before the battle, then rearing up on powerful hind legs and slashing their competitors with sharp claws.

Sounds

Auditory calls are used by predator lizards who are not afraid to draw attention to themselves. Predated lizards do not usually emit mating sounds.

green anole

The green anole lizard inflates its dewlap skin to epic proportions to ward off competitors and impress females.

©victoria.schell/Shutterstock.com

Recap: How Do Lizard Mate?

We’ve uncovered that not all lizards need to mate to produce offspring, but those that need a sexual partner have a range of signs, postures, and sounds to indicate they are ready to mate.

Lizard sexual reproduction looks unusual! The male holds the female’s head in his mouth and deposits sperm in her cloaca; after mating, they can remain twisted together for hours, potentially due to the spines, hooks, and knobs on their genitals.

Lizards are incredible animals, and this is highlighted in their reproductive abilities. Some lizards don’t even need a partner to produce babies!

The photo featured at the top of this post is © Huy Thoai/Shutterstock.com


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About the Author

Rebecca is a writer at A-Z Animals where her primary focus is on plants and geography. Rebecca has been writing and researching the environment for over 10 years and holds a Master’s Degree from Reading University in Archaeology, which she earned in 2005. A resident of England’s south coast, Rebecca enjoys rehabilitating injured wildlife and visiting Greek islands to support the stray cat population.

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