Sea turtles are one of the most fascinating marine reptiles CRAM Foundation (Conservation and Recovery of Marine Animals), which focuses on the study and conservation of these animals, we want to teach you the most possible about them. For example, could you tell how many eggs they lay in their nests at a time and how is their incubation?
How many eggs can sea turtles lay
It is difficult to be able to say exactly how many eggs sea turtles lay , since not only do we find that each species lays a different amount, but also, within the same species, there are many fluctuations in the volume of eggs they lay at each clutch. These variations may depend on genetic factors, environmental factors and the age of the animal, among other aspects.
Trends in the number of eggs laid by sea turtles by species are as follows:
- Green turtle: they can lay between 110-130 eggs.
- Loggerhead or loggerhead turtles: those from the Florida area usually score between 100-125 and those from the Mediterranean and Cape Verde areas usually score between 70-150. The most common is that they are around 100, but occasionally there are nests that are around 30 eggs.
- Hawksbill turtle: the egg laying of this species ranges from 80 to more than 200.
- Olive tortoise: in this species the clutches are between 87-120 eggs.
- Leatherback or leatherback turtle: they can make nests with an average of 110 eggs.
- Olive ridley, olive ridley or bastard turtle: they lay between 80-150 eggs in their nests.
- Australian flat turtle: This species lays 110 eggs on average in their nests.
What is the breeding season for sea turtles ? Is it different according to the species? The truth is that the season can change between the different species and, within it, there are even turtles that reproduce at different times.
These marine reptiles can have seasonal reproduction , such as the leatherback or leatherback turtle , or reproduction with more homogeneous patterns , such as the loggerhead or loggerhead turtle . In the case of the leatherback species, its reproductive season occurs when the climate where it nests is humid and warm. For example, in the American tropics it occurs between the months of February and July and, on the other hand, on the Atlantic coasts of Africa it occurs between the months of November and March. In the case of the loggerhead species, normally, reproduction occurs in early spring in all nesting areas.
Furthermore, sea turtles reproduce sequentially with very little variation throughout life.
- There are species that can make annual layings , that is to say every year, as in the case of olive ridley and olive ridley turtles.
- Other species make biannual layings , that is to say one year yes and the next year no, as in the case of the loggerhead and hawksbill turtles.
- There are also species that mix and there are seasons that present biannual clutches and seasons that present triennial clutches , such as the green turtle and the leatherback turtle.
How Sea Turtles Lay Eggs
Where do sea turtles lay their eggs? We might think that living in the seas they put them right there, but the truth is that they do mate in the water, but to lay their eggs they go to the beaches.
Some species have philopatry, that is, the females return to nest on the same beaches where they were born , the males do not. On the other hand, other species, such as the leatherback or leatherback turtle, vary greatly from one beach to another , returning less to the ones that were born and can even go to several beaches that are separated by many kilometers. However, what we do not know with complete certainty is what are the criteria that they follow to choose a beach, when it is not the one in which they were born. It is considered that they select it according to several criteria such as, for example: temperature, the absence of light, the type of sand and the texture it has, the underwater topography of the area, the rock formations and the vegetation on the beach , among others.
The process of laying eggs for sea turtles is as follows:
- The females of some species make their spawn entirely individually or with a few coincidences, but others do it in groups or massive arrivals.
- They choose a site in the sand and sometimes some females go there every time they go to nest.
- They use the fins to make the nest, removing the sand until they consider it to be an optimal size. Specifically, they use the front fins to make the camera and the rear ones to make the hole in the nest, in which they spawn.
- With their oviduct they lay the eggs in the nest, which are piled up.
- When they finish laying them, they cover the nest with the surrounding sand, which is what they have moved before, using mainly their back flippers and then camouflaging it with their front ones.
- As soon as they consider that the nest has been well covered, they return to the sea, already exhausted by the effort, and do not return to the nest at all.
Regarding how many nests each female makes in a single season , it is just as complicated to specify as the number of eggs for the same reason: various factors intervene that determine the laying of eggs. The trends in terms of the number of spawns per season and the days that elapse between one and the other are as follows according to the species:
- Loggerhead turtle: they make between 3 and 7 clutches and between one and the other they spend 10-15 days.
- Green turtle: they make between 3 and 5 nests and between them they spend from 12 to 15 days.
- Leatherback turtle: this species has an average of between 3 and 14 spawns and allows between 9 and 11 days between them.
- Olive turtle : they lay eggs between 1 and 3 times, allowing between 14 and 24 days to pass between nests when they do them alone, but they allow up to 30 days to pass when they make massive nests.
- Hawksbill turtle: this species lays eggs between 3 and 5 times per season and allows between 13 and 15 days to elapse between layings.
- Australian flat turtle: they make between 2 and 4 spawns each season, allowing between 13 and 18 days between them.
- Kemp’s ridley, olive ridley or bastard turtle: this species makes between 2 and 3 spawns and between each one they allow about 20-28 days to elapse.
As we have indicated before, the sea turtle eggs are left alone in the nest, because after laying them the mother does not stay to incubate, monitor and protect them. Therefore, the eggs are incubated thanks to the environmental conditions of the nest area. Depending on the temperature of the nest , the sex of the turtles can vary. Depending on the species, this changes, but, for example, in the case of the loggerhead, the average maintained 29.5 ºC is the temperature at which similar percentages of both sexes can emerge . On the other hand, if the temperature is higher than 29.5 ºC more or less maintained, more females will come out and, on the other hand, if it is lower, more males will come out.
After the incubation period, which varies in each species but, for example, in the case of the loggerhead it is usually about 2 months, the young begin to be born. ¿ How sea turtles are born exactly? Here we mention some aspects about the process:
- The small hatchlings found inside the nest tend to blend in at birth, as it has been observed that they emit sounds that could be used to warn each other.
- To break the shell of the egg and get out of it, they use their beak and their fins.
- When the eggs have hatched, the hatchlings remain underground for a few days, for example, in the case of the loggerhead or loggerhead it is 4 days, and then they begin to dig a way out of the nest.
- All hatchlings emerge at the same time , or practically all, to facilitate their exit from the nest hole and to ensure that more of them reach the sea.
- The percentage of newborns that reach the water is usually high, but it depends on each case. Normally, it was believed that only one out of 1,000 hatchlings would survive, but the success of hatching and emergence varies greatly between species and nests. This is due to natural predation and anthropic threats to which they are exposed from an early age, among other factors.
- The main strategy of these species to survive is called strategy R and it is about laying many eggs, but not spending energy on caring for them in order to spend energy on laying more eggs, ensuring that at least some turtles, which are much less than the number of Eggs laid but sufficient for the species to survive, reach reproductive age to continue the cycle.
How we can help sea turtles
As many of these turtle species are in danger of extinction or in a state of vulnerability, there are associations, foundations and other entities that are dedicated to caring for and studying them, as well as fighting for their conservation. This is the case of the CRAM Foundation (Conservation and Recovery of Marine Animals), which is dedicated to conserving marine life . This foundation is in charge of helping to conserve marine beings on the Catalan coast, especially the Mediterranean turtles.. When they receive a warning that a nest has been detected on a beach in this region, they guard it and take care of it until the young leave it. Once these emerge, a small percentage of the young are transferred to the CRAM Foundation facilities until they reach an optimal weight and size to avoid the first predators. This helps to ensure that it is somewhat easier for some of the new generation to survive until they reproduce.
If you ever see a turtle that needs help on the beach or in the water or if you detect a nest in the sand, do not hesitate to notify the emergency department, which in the case of Spain is number 112, and from there they will notify the foundation, association or entity dedicated to helping these species, such as the CRAM Foundation (Conservation and Recovery of Marine Animals). If you want to find out more about how you can help these animals, we encourage you to enter here and find out How to help the CRAM Foundation , as there are many options for this, such as, for example, collaborating by donating from € 1 per month to the amount you consider or Well, volunteering to do jobs at the recovery center.