Reptile & Amphibian Forums

` I'm looking for input on this situation. Guesses are fine. At this point, I'm ready to consider anything.
` My largest female Yellow began an unplanned mating session in November, 2002, at the age of almost 4 years. She and the male mated continuously through early January, 2003. Early in the the process, she ovulated to the point I thought she was going to burst.
` She was obviously gravid, and began to swell. Her appetite was strong through the first three months of gestation, then began to drop off.
` In the middle of June, 2003 she began to give birth to perfectly formed, dead babies. Some with their shed skins beside them. She did this for over two months, with breaks between births from a few days, to weeks.
` At the end of August she gave birth to the last three perfectly formed babies and two unfertilized ova. Total babies, 29.
` This long delivery period, and the condition of the neonates had me scared, for her. She is a giant, and totally tame and gentle. She is a loved pet. I didn't really care about the babies. I was happy that she got through it, had lost very little weight, and seemed healthy. Her appetite resumed, and she has been handled, and exercised constantly, since August.
` Last Wednesday, March 3, she looked bloated in the rear third of her body. She felt hard to the touch, in this area. I could feel a mass inside her. It was obviously uncomfortable for her, as she tried to avoid my touching here there.
` I decided to massage her, to see if the mass would move toward her cloaca. Over the next few days, I managed to move the mass over two feet, to within a foot of her cloaca. This seemed to be painful to her as she struggled and even slapped me with her coils, nearly dislocating my thumb.
` By Sunday afternoon, I had moved the mass to within two inches of her cloaca. She tapers down, at this point, and the mass was large enough, and hard enough, to make her scales stand up, including her scutes, for about 4 inches of her body.
` I was ready to rush her to the Vet, this morning. At about 5 o'clock a.m. she passed an unfertilized ova, and a decomposed baby. If you've followed the timeline on this process, it has been 7 !! months since she last delivered. 14 months !! since the gestation began. Since she and the male stopped mating, in early January, 2003, she has been isolated.
` I had hoped to produce young from these two Anacondas, as they are the two tamest and most gentle Boids I've ever encountered. The male has almost no feeding response, at all! I figured that they would produce some really tame babies. Also, they are both very large, for Yellows. If this is a sign that she will continue to have problems with reproduction, then it is not worth the risk.
` It is going to be a hard decision to make.
` I'd be happy to hear any input you have on this situation.

` Picture of what she produced, this morning.

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Wow is about all I have to say. As far as breeding her,I would not take the risk its just not worth it. What I would do is to take her to the vet anyway for a X-ray just to see if there is anything else in her. When it comes to our snakes its better to be safe than sorry. Keep us posted.

Wow, you have just provided some more evidence to what little there is about delayed fertilization in anacondas!

Since delayed implantation is, by definition, a mammalian trait, it must be delayed fertilization that has happened, which is already know to happen in some smaller snakes.

Cool! (Not cool for the babies, of course.)

Actually, from what you reported, I am surprised your snake is still alive - those rotting corpses could easily have killed her, made her septic.

Who knows why the babies didn't live, there are all sorts of guesses: something corrupted the sperm that was stored for delayed implantation - but this would mean fertilization and body formation ocurred, and then something went wrong. It is more likely that something went awry in respect to the mother and reproductive processes in her body. One simple guess is that she didn't bask long enough - at least, in the wild we saw that females who, for some reason, didn't bask as much while pregnant more oftenhad problems, still born. I had one strong, healthy female die right around time to give birth - actually she passed her due date, or due "month", and she died suddenly. When we necropsied her, she was full of dead, half rotten babies.

I would say it would be risky breeding her again - and you never know if personality traits, like being very docile, are genetically inherited. I rather doubt it.

Make sure you write down the dates, etc. of everything that happened. You could even publish this as a note in Herpetological Review.

Renee

Rich,
I remember when you posted about the still births last Fall. Very unusual situation. From the experiences I've had with breeding boas and anacondas over the years and the timeline you gave, I would say that the gestation period your female experienced was completely typical for anacondas. The breeding period and ovulation you observed would indicate the initial birth very close to the period that it actually occurred. The young were full term and even shed before birth. Therefore, I don't believe there was a gestation problem, or lack of heat during this period. It appears that when the young were full term and ready for birth, the females reproductive system failed for some reason and the young were retained for a few weeks past the natural birth point. The young apparently survived within the female for some time and even went through the initial shedding cycle while still within the female. As time went on the young eventually expired and were expelled over an extended period. Pythons that retain eggs past the due date for laying, many times release them like this over an extended period of time. Obviously, not all the young and unfertilized ova were expelled last Fall and I believe the female ovulated again a short time ago, close to the same time as last year. The retained young and ova probably acted as an obstruction causing the swelling you saw last week. It is great that you were able to remove them in the way that you did. I would watch her very closely and if she swells any again or acts tender in this area for very long, have a vet check her out. Actually a sonagram would probably be a good idea at this point, as x-rays will not show the soft tissue very well if any other material is still retained. I would hesitate to breed her again as boids that retain young or eggs like this are highly prone to this occurring in subsequent breedings. Good luck and keep us posted.

Kelly

Hmmm, reading Kelly's response made me realize maybe I hadn't read your timelines more carefully. Darn - I had an extra year in there, somehow, between that last "baby" and mating. That's what happens after all day in the field when it's hot.

Well, there still definitely could be some evidence for delayed fertilization, but unfortunately now it isn't a sure thing. What amazes me is, that if there wasn't delayed fert., and she actually expelled babies months after gestation was complete, I am stunned that they stayed in her that long, and she didn't get very sick and die.

I'd say she's lucky to be alive, and maybe hold off on trying to breed her, at least for a while.

Renee