|
|
|
|
--------------------------------------------------------------------------------
Breeding Tree Boas (Corallus)
--------------------------------------------------------------------------------
Typical to most boids, there is a simple "formula" that can be followed which
mimics the natural seasonal changes which trigger breeding behavior, however
this is but a small fraction of what is necessary for the successful breeding of
treeboas belonging to the genus Corallus. The most important ingredient is
patience, as with anything else Corallus. Breeding occurs biennially and will
only be successful in those animals that are well acclimated to a captive
environment and in the best health.
First and foremost it is imperative that you begin with animals that are
sexually mature as well as in perfect health. The latter probably deserves the
most emphasis because most animals will not begin the proper breeding behavior
unless they are fit enough to undergo the rigors of stress and the fasting that
is so common in males of this genus. It is important that a good fat reserve is
built up to carry them during these lean times, this is also important for
females in the sense that ovulation may not successfully occur if the females
weight is inadequate. Although most females will initially feed during their
pregnancy, most will go off feed during the latter portion of their term
(usually the last 3rd) and so a good fat reserve will help the female carry on
until parturition occurs. As mentioned earlier, it is important that you are
working with animals that are sexually mature in order to maximize the
possibility of success in reproducing this species. Captive born specimens
should be at least 4-5 years of age and imported specimens should exceed 4.5
feet in length. This size range ensures that the animals are sexually mature and
capable of reproduction however it does not guarantee anything. As a rule,
imports should be thriving and trouble free for at least 1 year before
attempting to breed them, rushing things may only endanger them.
Off-season Maintenance
From about May to November I keep adults separated in their own individual
enclosures which aids in stimulation when they are introduced in the beginning
of December, this also makes it easier for me to monitor their individual
progress. For the most part, they are kept on maintenance diets which consist of
a small weanling rat about every 14-20 days for emerald tree boas and every
10-14 days for Amazons which are fed smaller "fuzzy" rats. As a whole I like to
keep females very well fed and the males a bit on the thinner side. I've noticed
that obese males rarely ever engage in any courtship behavior. Large, vertical
indentations caused by folding scales are a sure sign of obesity and you should
immediately cut back on feedings. It's my opinion that we grossly overfeed some
Corallus in captivity, especially emerald tree boas which suffer no ill effects
from fasting for several weeks at a time providing they are in perfect health.
Throughout the off-season the environment remains somewhat steady with daytime
temperatures peaking at about 83- 84F and nighttime lows dropping no less than
about 77F. This is important because you'll want to widen this gradient later on
come the breeding season.
Humidity should remain relatively constant and not drop below 60% at any time in
order to prevent the risk of a respiratory infection, it should peak at about
85-90% during the day and back down to the upper 60 percentile during the
evenings. Remember to keep a good airflow within the enclosure, the key to
proper Corallus maintenance is achieving the proper relationship between airflow
and humidity.
Seasonal Cooling
Around early November, I begin to gradually drop my evening temperatures from
the stable 77-78F of the summer season until a night time low of about 70-72F is
achieved by the first week of December. It is vital that you do this GRADUALLY,
perhaps dropping 1-2F during the evening hours, to drastic of a change will
bring about complications. At times my temperatures may drop as low as 68F but I
don't advice a dip quite this low, just know that these levels may be reached
but the threshold doesn't lie much farther beyond that. It is imperative that
during the day a daytime high temperature (DTH) of about 83-85F is achieved in
order to offset the night time lows (NTL) which prevent any risk of respiratory
infections. A basking spot with a higher temperature may be provided as long as
there is an adequate retreat that will reduce the risk of overheating, the
basking spot will also prove useful for the soon-to-be gestating females.
Around this time I also set my misting systems to begin spraying about 6 times a
day at 1 minute intervals throughout the day. It is important that humidity
levels peak at or near 100% and drop down to about 70% in a 24 hour cycle.
During these times of high humidity be sure to monitor your air quality in order
to prevent mold or fungal growth within the cage. As long as the air within the
enclosure does not become stagnant this will not occur. This setting is kept
until about mid May when the breeding season begins to wain. Afterwards the
misting system is returned to 2 spraying cycles that last about 2-3 minutes
each.
After about 2 months of exposure to the temperature gradient and increased
humidity most males will begin to display courtship behavior, in most cases it
comes about after a shed. Courtship behavior consists of tail-writhing all over
the enclosure and if you look closely you will easily notice his spurs
feverishly stroking whatever his vent comes in contact with. At this time you
can introduce the pairs and the male will begin to spur the female which will
stimulate ovulation and eventually bring about her readiness to mate. I prefer
to introduce females into males' cages as this way the male will not be
disrupted and continue to court which is necessary to achieve the proper
breeding stimuli in the female. Initially, a female may be reluctant to accept
the male's advances but with enough courtship she will eventually come around.
It is helpful to wait until the female has just completed a slough which will
ensure a strong pheromone presence and aid in breeding stimulation. Usually
around March to April you may see the pairs actively copulating. Don't be
alarmed if it doesn't happen immediately upon introduction, sometimes it takes
Corallus a while to "wake up" and start breeding, on the other hand it may
happen immediately..there is no set formula for this. Multiple copulations
usually ensure pregnancy so it is very important to not disturb them during
these rituals. Multiple males may help to increase a breeding response although
this can be a dangerous undertaking, never leave two males unattended during
this portion of the season as it may result in the death of one. A recently shed
skin placed within the cage of a conditioned male may bring about the desired
response without the risk. Some males may be overly aggressive when mating with
the females so keep an eye out for breeding stress which will result in the
female forced to the floor of the cage. Prolonged stress will eventually become
detrimental to the female's health and breeding success as well, if frequent it
is best to separate the pairs and allow for a resting period of several weeks
after which the female may be re-introduced.
Success
Several weeks after witnessing copulation obvious swelling will be present in
the female, this will be the point of ovulation. Ovulation will usually occur
anywhere from 2 to 3 months after a successful mating but as with everything
else involved with this genus, there are exceptions to this rule. I personally
had one female ovulate and give birth to 1 live and several stillborn babies
even thought she had NO CONTACT with any males for over a year. Soon after
ovulation the females girth will return to a more laterally compressed shape and
you may notice that she will spend more and more time basking after this point.
A few weeks later (about 20-40 days) she may undergo a post ovulatory shed, this
is a good indication of pregnancy although as usual, it does not necessarily
mean she's not gravid if she doesn't undergo this shed.
A good sign of pregnancy is that she will soon seek out a higher heat gradient
under which she will bask while her developing embryos grow. It's important that
you provide a basking area of about 95F, a higher temperature can be provided as
long as there is an adequate gradient which will allow her to retreat to about
70-75F when she feels the need to. Radiant heat panels and ceramic fixtures work
best for providing the necessary environment for a basking female. You'll want
one of these heat sources over an incandescent bulb for the main reason being
that no light is emitted and the basking area can be provided on a 24 hour
basis. Some breeders choose to shut the basking lights/areas off in the evenings
but I have never chosen to do so with excellent results. Upon confirmation of
the gravid state of a female, I return temperature and misting regimens back to
the off season mode which is characterized by milder fluctuations and less
frequent mistings which in turn mean a lower mean humidity.
Gestation in Corallus varies considerably but for most species a time frame of
about 200 days will pass before the embryos go full-term and are born, this is
all dependent upon how many degree-days are allowed (the amount of time she
basks). Based upon personal data and some of that submitted by my colleagues it
seems that the average time frame between ovulation and parturition falls within
175-225 days. A few weeks prior to giving birth the female will eventually start
to move away from the heat source and go into a pre-parturate shed, this shed
can be expected anywhere from 1 to 3 weeks prior to parturition. A shed may not
always occur prior to giving birth but a good sign is that she will be unusually
aggressive, especially given the placid nature of most Corallus (kidding).
Usually like clockwork, about 2 weeks after the shed, she will move to a high
position within the enclosure and give birth to live babies. At this time the
neonates should be immediately removed and placed in individual containers as
cannibalism between the mother and her offspring has been noted in emerald tree
boas, it is not known at this point if this may be an accidental incident as
many animals are known to ingest stillborn young and unfertilized ova in efforts
to gain back many of the lost nutrients of this biologically expensive ordeal.
The approximate time frame given above can almost always be shortened slightly
for Amazon tree boas. On average parturition can occur as early as 150 days
after ovulation in Amazon tree boas and pre-parturate shed are less common. This
is no surprise given the relatively fast metabolisms that Amazon tree boas
display. For reference purposes, the following table was created by Christian
Eiffel according to data provided by myself and other colleagues and was
submitted to the Corallus Mailing list.
1st Copulation Ovulation Post-Ovulatory Shed Pre-Parturate Shed Birth
+-------------------------------------+-------------------------------+--------------------------------+---------------------+++
60-80 Days 20-40 Days 90-110 Days 7-20 Days
After birth, normal feeding schedules may resume for the female with the
exception that you'll want to start off with smaller-than-normal prey in order
to not overtax the female's delicate digestive system as in most cases the
females will be recovering from a brief pre-parturate fast. In most cases I have
also noticed that post-parturate females will readily, even eagerly except their
first meals.
After the birth of your neonate Corallus is complete, it is vital that you sit
back, take a deep breath and enjoy the beauty of what you have just witnessed
for I can think of few sights that are as breathtaking and gratifying. Although
the genus as a whole is regarded as difficult to successfully reproduce it is
not an impossible undertaking and as long as much TLC and patience is provided,
the task at hand is not a difficult one.
* I would like to thank members of the Corallus mailing list for their
assistance in this article *
Copywritten 2000 Danny Mendez
This article may not be reproduced wholly or in part without expressed written
consent.
bravenet.com