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scientific site about Boa constrictors
Breeding boas...2006-08-28

As autumn and winter months are approaching, most boa keepers that have adult animals certainly consider breeding their boas.

First of all, there some rules regarding breeding that one should observe in order for animals safety:

- all specimens must be in excellent health condition
- any kind of illness makes boas inappropriate for breeding trials (until they recover completly)
- boas under age 4 years are not recommended for breeding

There are several misbeliefs circuling around breeding boas. One of them is related to their size. Most snake keepers believes that most important factor is animals' size. Therefore, these keepers do whatever it takes for the animals to achieve that certain, misunderstood size. As a result, they overfeed boas making them unawarely unable to reproduce. One can often find boas on the market that are 2 years old and 2 meters (6,5 ft) long already. Those animals are definitely overfed and unlikely to breed successfully.

Age is a much more important factor than size when it comes to breeding. According to our experience, a 4 years old, 1,5m long boa with a moderate feeding schedule applied has much more chance to reproduce than a 2 years old, 2 m long, obese specimen.

Most boas tend to show breeding behaviour in the cooler months. On our latitude, this generally means month from October to January, however- due to dometication -this period often extends.

Copulation can take several hours...

It takes 1-12 weeks for the ovulation to take pleace after copulations. Both midbody swelling and refusing food can indicate ovulation. This swelling will deflate in few days and is followed by a shed. This Post-Ovulations-Shed (POS) is the generally accepted time of fertilization, this is the first day of gravidity. Most females will restart feeding afther POS, however we have also noticed females that never took food again until giving birth. Gravid females should be fed with rather smaller preys more frequently.

Though length of gravidity can vary from 90 to 180 days, most females will give birth between 110-120 days. If mulch-type bedding is used in the enclosure, females often dig out a pit in the substrate prior to birth, where she will drop her babies in. Females also often tip their newborns by their nose to encourage them breaking the sac. Unfertilized ovas (slugs) and stillborn babies are generally eaten by the mother, however this behaviour is not commonly seen under captive circumstances.

Newborns in a pit (dig out by the female prior birth)

Most crossbred boas are easy to breed with no stimulation, however many purebred localities show much less willingness to reproduce.

Male Suriname boas often show less willingness to breed than other localities.

I must emphasize that breeding is potentially dangerous for animals. Animals involved in breeding could have more health issues and average shorter lifespan than their captive kept relatives that are not involved in breeding.

Animals stimulated (=being in cooling period) must not be fed!
2 weeks prior to start of cooling, animals must not offered preys!
One must not powerfeed boas that refuse to feed in the breeding season. Females can act very aggressively after giving birth, therefore should be handled with great precaution.

Botond Ádám

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