By Margaret A. Wissman, DVM, DABVP
I was wondering if you can help me. One of my female water dragons has given birth to one slightly larger than usual egg. Is this normal? She gave birth to nine eggs approximately four months ago; six of them were viable. It was a very straightforward and problem-free pregnancy.
I am now quite concerned. Judging by her weight and the extra loose skin around her sides, there are definitely no more eggs inside her, and her appetite has come back. Also, can a water dragon give birth to one egg at a time over a long period? Any help would be greatly appreciated.
Before I go on to answer your questions, I feel the need to correct your terminology a bit. “Giving birth” is a term usually reserved to use in mammals that actually give birth to a live offspring. Likewise, the word “pregnancy” is only used when dealing with mammals carrying their offspring within the uterus of the female. When dealing with reptiles, we usually use the term “oviposition” which means egg-laying, instead of “giving birth.” When talking about a female that is developing eggs, we usually say “gravid” and not “pregnant.” “Pregnant” is a term sometimes used to denote a female herp that gives birth to live young and not eggs. A female herp that lays eggs is called “oviparous.”
Now that we have that straight, let’s answer your questions. First, reptile eggs are usually uniform in size and shape. So, it is not normal for one egg to be significantly larger than the rest. Sometimes that occurs if the herp develops a malformed egg or one with two yolks.
I am not quite certain what you are telling me that you are so concerned about now. You said that you didn’t think she had any more eggs left to oviposit and that she appeared thin and had resumed eating again. All of that sounds quite normal to me. If you were concerned about the larger egg, well, she did pass it, so all’s well there, too!
If you have specific concerns that I have not addressed, it is time to pick up the phone and call your herp vet for your water dragon to be examined. Ultrasound or radiology may be employed to determine if there are any retained eggs or other reproductive problems present. It is normal for a female that has just oviposited to be thin with loose skin and as long as she is eating, she will regain her lost weight.
To answer your last question, it is certainly not normal for a female water dragon to lay one egg at a time over a period of time. Usually, the entire clutch is oviposited all at one time, unless there is a problem. This may be a result of improper substrate for digging to stimulate oviposition, from low calcium levels, from infection or damage to the shell gland, skeletal abnormalities, nutritional disorders or from an abnormally large or misshapen egg. Medications may be administered by a herp vet to stimulate oviposition, usually after calcium and vitamin administration, once it has been determined that the remaining egg(s) can successfully pass through the pelvis.
I suspect that your lizard is doing fine, but don’t take my word for it since you are so concerned. This is the time to call your herp vet and get your girl evaluated for any problems.
Need a Herp Vet?
If you are looking for a herp-knowledgeable veterinarian in your area, a good place to start is by checking the list of members on the Association of Reptilian and Amphibian Veterinarian (ARAV) web site at www.arav.com. Look for DVMs who appear to maintain actual veterinary offices that you could contact.