Differences between Snake, Lizard, and Turtle eggs
Being able to identify reptile eggs is important as it helps you know whether those eggs in your backyards are simply turtle eggs or the eggs of a more menacing reptile such as a snake and whether you need to relocate them or not.
Additionally, as a reptile breeder or enthusiast, such knowledge comes in handy. As you may already know, not all reptiles lay eggs, some birth live babies.
Reptiles that produce live young are generally referred to as ovoviviparous (meaning the eggs are incubated and hatched inside the mother). While reptiles that lay eggs are referred to as oviparous.
A number of snakes do not lay eggs. Some North American ovoviviparous reptile species include cottonmouth, copperheads, ribbon snakes, rattlesnakes, and the common garter snake. Most American snakes are oviparous (lay eggs), these include corn snakes, milk snakes, pythons and countless others.
The first thing most notice about snake eggs is the leathery feel of the shell. It feels more like a pouch filled with gooey liquid. The leathery nature of the egg makes it more durable and less likely to crack.
Snake eggs are usually elongated and less circular in nature. Snake eggs also tend to be stuck to one another. You usually find snake eggs in sheltered damp spots.
Snakes lay eggs in humid places as the eggs tend to draw water from its environment and swell up. When in a dry environment, the permeable shell allows water to escape the egg leaving the egg shriveled up.
As a snake egg draws water, the albumin grows alongside the egg. A snake egg increase in size until it hatches.
Identifying A Snake Egg
There are several characteristics, such as shape, hardness, and appearance, which you can use to identify a snake egg. We have already spoken about some of these characteristics in the previous section. When identifying a snake’s egg, you need to process with cautious so as not to detach the embryo and kill the egg.
As snake eggs are leathery, if the egg has a hard shell then it isn’t a snake’s egg. It is likely a bird egg. When examined under bright light, you should be able to make out the silhouette of the embryo within the shell. Don’t handle the egg for long. Put it back into its natural habitat.
Snake eggs are generally oblong. They are barely circular in nature. Most American snakes have eggs shaped like that of a bird’s egg. This is a big identifying feature.
To properly identify the egg’s species (or tell whether what you actually have is even a snake egg) you can contact your local zoo, wildlife sanctuary, game warden or herp vet. They may even be able to identify the species. This is rare though, as most snake eggs look the same.
Snake eggs should also be moved carefully and hopefully by a professional (such as a snake breeder) if you find the eggs underneath or in your home, or backyard, and you want them moved. If you find snake eggs in the wild, it is best to leave them as they are so as not to damage them.
The eggs usually take between 50 to 60 days to hatch dependent on temperature. The higher the temperature, the shorter the incubation period is. Snake eggs must be kept in an incubator. Incubation temperature is usually around 80 F. The eggs must be placed in humid substrates such as moist peat moss, coco coir or even paper towels.
There are two types of sex-determining mechanisms in reptiles. This includes genotypic sex determination (GSD) and temperature-dependent sex determination (TSD). With genotypic sex determination, the sex of the unborn young is determined by sex chromosomes passed on by the parents, like in the case of humans and all snakes.
Snakes have Z and W chromosomes, the males are homogametic and have only Z chromosomes (ZZ). Females are heterogametic and have ZW chromosomes.
Turtles, unlike snakes, are strictly oviparous and as such lay eggs. These include aquatic turtles, semi-aquatic turtles, and land turtles.
Unlike snake eggs, turtle eggs are usually rounder although some species lay slightly oblong eggs. Turtle eggshells are white to cream. While some turtle eggs are hard to touch such as a bird’s egg, some are leatherier to touch.
The hardness or rubbery nature of a turtle’s egg depends on whether or not the egg needs to absorb water. Hard-shells are less permeable and allow less water through, unlike leathery shells. Also, turtle eggs are smaller in size as compared to snake eggs.
This is because turtle eggs pass through narrower gap. Turtles generally lay fewer eggs than snakes than do. The number of eggs a turtle can lay in a go is directly proportional to the turtle’s size.
While smaller turtle species such as common musk turtle (Sternotherus odoratus) lay as few as 1 to 9 eggs, large species such as the leatherback sea turtle (Dermochelys coriacea) can lay as much as 400 to 500 eggs per season.
Turtle gestation depends on the species. Incubation usually takes between 45 to 75 days depending on incubation temperatures. For instance, for Trachemys scripta, gestation period usually lasts for 60 to 95 days. For another species, such as musk turtles, the gestation period can last for 63 to 84 days. Most turtles lay several clutches a year.
We have already talked about the two types of sex-determining mechanisms in reptiles – namely genotypic sex determination (GSD) and temperature-dependent sex determination (TSD).
As we already mentioned genotypic sex determination (GSD) is based on genetic material (chromosomes of the parents). The sex of most turtles is determined by temperature. As such, small changes in temperature can result in drastic changes in the sex ratio of a nest.
With turtles, generally low temperatures, which include 71 to 80 F (22 to 27°C), results in one sex, while eggs incubated in high temperatures, which include 86 F (30°C) and above, result in the other sex.
Of course, these temperatures vary from one turtle species to another. For the popular pet turtle species Trachemys scripta, which includes turtles such as the Cumberland slider (Trachemys scripta troostii), the red-eared slider (T. s. elegans), and the yellow-bellied slider (Trachemys scripta scripta), temperatures of 79 to 82.5 F (26 to 28 C) produce all males, while temperatures of 88 F (31 C) and above produce all females.
Temperature between 82.5 F (28 C) and 88 F (31 C) produce a mix of males and females with lower temperatures producing more males.
While most lizards lay eggs, not all lizards do. Some popular lizards that are lay eggs include most chameleon species, all gecko species, most iguanid species, all monitor lizard species, and water dragons. Lizard eggs vary in sizes as well as in shape and color.
As already mentioned lizard eggs vary in size just like snake eggs. Like snake eggs, most lizards have leathery eggs which allow water to enter the egg, Lizard species with hard-shelled eggs include arid-living lizard species.
This is necessary to prevent moisture loss. Infertile lizard eggs are generally very soft with a texture of a water balloon. They also usually look shriveled. Similarly, If moisture content of the incubation substrate is low, lizard eggs usually shrivel up and die.
Identifying A Lizard Egg
Identifying characteristics include feel, shape and size. Lizard eggs are generally leathery to the touch and are quite small, much smaller than snake eggs.
It isn’t advisable to examine a lizard’s egg under bright light. Lizards aren’t chickens and its likely you won’t see anything special. Since lizard egg embryos attach themselves to one side of the egg, flipping the egg can cause it to die. It is very easy to pick up a lizard’s egg and not put it back right.
As with snake eggs, most lizard eggs are oblong. Small lizards lay small eggs. For instance, the leopard gecko and crested gecko eggs are about half an inch long when freshly laid. Larger lizards such as the argentine black and white tegu lay larger eggs over an inch in size.
Since lizard eggs look similar to snake eggs, telling them apart can be near impossible if they are of the same size. Generally, lizard eggs are smaller than snake eggs are.
The incubation period of lizard eggs also depends on the species. As lizard eggs are leathery, it is important that the incubation medium is moist. For geckos, incubation usually takes 35 to 89 days depending on the temperature.
The sex of some species is determined by temperature while some are determined by sex chromosomes. The sex of geckos is generally determined by temperature.
For leopard geckos, temperatures of 80 F produce all females, while temperatures of 88 F (31 C) and above produce about 98 percent males. At a temperature of about 87 F an equal number of males and females are produced.
The sex of the bearded dragon, on the other hand, is determined by a ZZ/ZW sex chromosome system just like snakes. Makes possess two Z chromosomes, while females possess ZW sex chromosomes. However, at high temperatures, beardies with male chromosomes may develop as females.
Since many snakes, lizards, and turtles lay eggs near human settlements, it’s important to be able to tell the difference between different reptiles’ eggs.
For starters, the size of the egg is usually related to the size of the animal. As such, the smaller lizards and turtles lay smaller eggs. Most eggs with leathery shells that are over an inch in size are usually snake eggs.
Additionally, a lot of snakes such as rat snakes and corn snakes lay eggs that are stuck together. If you have any comments or information regarding snake, lizard and turtle eggs, we would love to hear them.