Thanks for the info!
It is very interesting to me to compare events and successes between wild and captive animals.
Yes, that's a huge male, we found some that size (near deeper water) but it is certainly not the norm in the Llanos. elsewhere, it could be; there is always the "researcher bias" of catching these animals: larger animals will be near, and in, deeper water, and we are typically limited to where we search by how shallow the water simply b/ if the water is too deep, they'll just swim away in a heartbeat, and are too hard to catch. The best chance to catch the real big ones is when they are basking, digesting (and part of them floats and is visible), or in a breeding ball, which are found in very shallow water or out of water. Also, large size is correlated to depth of water year-round, and the Llanos is highly seasonal, and dries up a lot, (unlike, say, an Amazon tributary)For example, we found our biggest snake in an igapo in eastern Ecuador, near a deep(er) river.
We did a lot of data collection on breeding, and even with the wild caught aniamls we did have problems, and are still pondering over what may be the cause. Usually, (thanks to the radio transmitters) we'd catch the female "just" before giving birth, which is a time window of about 1-2 months with these wild ones. We had some that gave birth to lot of stillborn, and a couple that never even gave birth, and so of course died (one was Zuca, an old favorite, about 5 m, very sad).
After assessing which ones did well and which ones didn't, I have a feeling a couple things are happening regarding being captive, but of course, we have no data of birth and mortality from wild births to compare anything to, to know anything for sure. But regardless, it appears that even though these girls are extremely hardy when it comes to healing injuries, they are rather sensitive to stressors during pregnancy. There seems to be a correlation between degree of handling and increased problems regarding birth and babies. Or, what may be happening is that "handling" (we caught them, put them in the enclosure, and left them alone) simply disrupts their natural behavior for a while, what with the enclosure; stress of being relocated, etc., and they bask less. We did worry sometimes that basking didn't seem as optimal as it should have been. (Then again, what is "optimal"?)Certainly, basking as much as possible is important for these females, and makes a big difference in baby mortality.
I do know one thing I can say for sure, although granted this may be less of a factor in captive, oft-handled females: the less handling while they are pregnant the better, to minimize stress and maiximize basking.
I don't know if this is common knowledge among breeders (not being a captive breeder myself), but the females do not eat throughout the entire pregnancy - risk of injury to the babies via injury from a bite of a prey (which is quite common, and leave significant scars) is too great. So, the females have adapted to being - or needing to be - quite fat before they breed. I could usually easily tell which ones were breeding, and which weren't, based on girth, even before mating. In the wild, this means that a female very rarely breeds 2 years in a row, it takes too long to build up body weight and fat to do so every year, especially without eating the ~ 7-8 or so months between mating and breeding, and the nergy it takes to produce so many babies.
I'm now writing an article on anaconda conservation, but intend to do another on breeding in the future,once I can do some work with the babies and transmitters, so this is interesting information for me, thanks!
Cheers,
Renee
