I often hear people talking about "candling" eggs to check if the animal inside is still alive or not.

What is this and how does it work?

  • 1
    Short answer: an egg is slightly translucent, so holding a candle behind an egg will allow you to see movement inside it cast by the shadow of the baby on the shell. If I remember, I'll turn this into a complete (and referenced) answer later.
    – ClickRick
    Dec 22 '14 at 15:08

Basically candling a egg is when you use a candle or a light to see through the egg shell and see the creature inside. By viewing the inside of the egg you can see if it is still alive, what animal it is and other details about the animal.

From Wikipedia:

Candling is a method used in embryology to study the growth and development of an embryo inside an egg. The method uses a bright light source behind the egg to show details through the shell, and is so called because the original sources of light used were candles.

Also, Candling can be used to determine details about other eggs, such as Chicken eggs and not just reptile eggs.


  • You need a bright like and a dark room for the candling. A flashlight will work.

Place the larger end of the egg (where the air sac is) directly against the light. Hold the egg near the top, between your thumb and forefinger. Tilt the egg slightly to one side and rotate until you get the best view.

You can just point the light at it and move the light around until you see something. This is what I do and I find that by not following a schedule you learn more.

You can candle most eggs immediately to see what's going on, but in some you have to wait.

Candling Reptile Eggs

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