Turtles are undoubtedly one of the most unique anatomies in the animal universe. With an attached shell that protects them from predators, and an innate ability to swim, turtles are one of the few species that spend significant time both on land and in water.
Now this might make you wonder, how are turtles born? Are they born in the water or on land? Well, you should know that turtle eggs are always laid on land. However, they have a unique egg composition that allows them
Do turtles have amniotic eggs?
Yes, turtles do have amniotic eggs. This allows baby turtles to stay protected from predators, while also providing a semi-aquatic environment that helps them develop and grow.
Amniotic eggs were a huge evolutional advancement for turtles, as it allowed turtles to lay their eggs in dry environments. This capability is one of the main things that separate them from amphibians, who can only lay their eggs in wet environments. The development of the amniotic eggs is one of the main reasons turtles have been able to live on dry land.
In short, an amniotic egg is unique in that it provides protection for the embryo, while also allowing carbon dioxide and oxygen to pass through the shell. To fully understand the importance of an amniotic egg, you should know what it is made of.
What is an amniotic egg made of?
An amniotic egg is comprised of four key sacs, all of which play a key role in the development of the embryo. The four sacs are:
- Chorion: The chorion is responsible for allowing oxygen to penetrate the shell and reaching the embryo. It also helps collect carbon dioxide released from the embryo, and removes it from the shell.
- Amnion: The amnion is located inside of the chorion. Its main responsibility is to ensure that the embryo remains moist. The embryo is at risk of improper development or even death if the shell becomes too dry.
- Allantois: The main responsibility of the allantois is to collect waste from the embryo and remove it from the shell. It also helps the chorion with the transportation of oxygen and carbon dioxide.
- Yolk: The yolk is essentially the stomach of the egg. It is responsible for storing and digesting the nutrients for the embryo. Essentially, the yolk is what the embryo eats while is incubates inside of the egg. As the embryo grows larger, the yolk decreases in size.
Below is a picture of an amniotic egg
What animals have amniotic eggs?
Now you might be wondering what other animals have amniotic eggs. Animals with amniotic eggs include reptiles, birds, and mammals. Now you might be confused to see mammals on the list.
Mammals do in fact have amniotic eggs. The eggs are just stored inside the mother’s womb, in the placenta, instead of being released outside of the mother’s body. The only mammal that releases eggs outside of the mother’s womb is the duck-billed platypus.
