Tuesday, February 12, 2013

Keeping and Breeding Varanus prasinus (email response)

I get tons of emails asking me about the care and breeding of tree monitors.  Unfortunately I don't always have the time to give a lengthy response.  I figured I would post the latest one I replied to so others who have the same questions can read it here.


I will be happy to help you.  The key to breeding is having healthy well acclimated adults.  Once the adults are healthy and being cared for properly they breed without needing to do any special changes etc.  The ideal situation would be to acquire very young prasinus and raise a male and female together.  During this time they will bond and upon reaching adulthood will start breeding regularly.  There are two benefits to raising young prasinus together in captivity, 1). Since they are young they will be adjusted to captivity as adults and not be spooked as easily when you have to clean the cage, do health checks,feeding, breeding and digging up eggs.  Wild caught adults take years to fully adjust and will hide from view making normal behavior unobservant.   They also stress easily when making changes to their cage or change in routine. 2).  Young prasinus raised together will bond and breed, wild caught adults do not always bond. If a pair doesn't bond they will not breed even though one is male and one is female.  I have seen this with some of my other tree monitors, V.reisingeri and V.macraei.  In these situations I have had to try putting together different pairs.  

To maintain healthy animals you first need to quarantine new monitors and take them to a veterinarian for a health check and fecal exam.  Since these lizards stress easily they are prone to infection during capture, transport etc.  All of the wild caught monitors I have acquired had parasites.  Pinworms, hook worms and different types of stomach worms mostly.  This was cured by giving a dose(by weight) of panacur to kill adult worms, then waiting 7 days and giving another dose to kill newly hatched worms as the panacur doesn't kill the eggs during the first dose.  During this time any feces should be immediately cleaned up to prevent reinfection while treating. After two weeks another fecal exam should be done to make sure the panacur killed all the worms.  The second most prevalent infection I have seen in these monitors is respiratory illness.  If this is noticed in the beginning stages it can be easily cured with 14 day oral treatment of the antibiotic enrofloxacin.  If the infection is progressed the infection may not fully respond to treatment, for example the lizard may appear to be cured but after a few weeks or a month the infection will reappear and treatment will need to be given again, sometimes with baytril instead of enrofloxacin. The least common illness is fungal infection.  This looks like scars or gray soft areas on the skin that spread or become infected, peel etc.  This can be cured by applying conofite lotion to the effected areas once daily for a week, in more advanced cases maybe two weeks.  Severe fungal infection will need an oral antifungal medication given daily for two months.  The type of medication depends on which species of fungus it is and so it must be grown on culture and tested to see what medication it is sensitive to.  Fungus spreads through the air so it is very important to have these lizards in a separate room as far from other reptiles as possible, ideally it would be better if the were in a separate building all together.  There is a type of fungus, CANV, that has been known to kill entire reptile collections just through air transmission.  

Once the monitors are healthy they should be placed in an enclosure no smaller than 6 ft tall, 4 ft wide and 2 ft deep, bigger is always better though.  The enclosure should have two basking areas, one for each monitor.  I have one area at 120 degrees and the other area set to 110 degrees so they may choose where they want to bask.  I also offer UVB that can be utilized with or without a heat basking area.  During the month my female is gravid she chooses to bask under the UVB light without heat, this tells me she needs this for her developing eggs.  I'm sure you know of the relationship between UVB, vitD and calcium and calcium being needed for egg production.  If you don't I can explain it in another email. Humidity in the enclosure should be high to simulate nature, no lower than 80%.  If they do not have proper humidity they get dehydrated and develop stuck shed which can result in tail tip and toes falling off due to necrosis.  A water dish big enough for the monitors to fit in should be used but I rarely see them drink from a water dish as they prefer to drink fresh water sprayed from a bottle or misting machine.  Substrate should be anything that holds humidity, I use moss and cypress mulch.  Do not use rocks or pebbles because these can be accidentally ingested causing death from impaction.  I have seen this in young monitors mistaking substrate or cage decor for food.  The sense of smell is very powerful and if anything in the cage smells like food from food being dropped on it etc, they will try eating it and ask questions later.  Once I had a young tree monitor try to eat my ear because I had been touching crickets and brushed my hair back behind my ear with that hand, he smelled my ear and latched on for several minutes until he realized my ear wasn't food.  Food is preferably eaten off the ground in a dish midway up in the central tree I have.  These monitors do not really go to the ground and spend most of their time in the upper half of the enclosure.   They need a lot of branches for climbing, positioned vertically,horizontally and diagonally.  They also like climbing in vines and foliage.  The walls of the enclosure should also be climbable, I use cork sheeting but I have seen others use lattice.  Provide a few hiding areas, these can be hollow cork tubes or something similar.  Provide at least one nest box, this should be completely filled to the top with damp moss and fine cypress mulch or dirt.  The nest box should be placed higher up in the enclosure and be around 3ft tall, 1ft deep,1 1/2 ft wide.  I have played around with different sized boxes and this seems to be the size they prefer.  You will know if the female likes the box if she goes in, digs a tunnel and lays eggs all in one time.  If she goes in and digs for awhile and comes back out, goes back to dig again etc. or only lays one egg at a time etc. then she is not happy.  It is normal for females to go in the nest box prior to laying eggs but you can visibly notice a difference in these times verses when she wants to lay her eggs and doesn't feel comfortable doing so.  Hatch rates go down the longer a female waits to lay eggs so nesting is important.  The entrance to the box should be a hole just big enough for them to fit through.  I have a small branch attached under this entrance hole on my nest boxes as well.

Diet is debatable among keepers.  Some feed rodents as the main staple in diet but I choose to feed insects as a main staple.  I feed mine around 1-2 dozen insects a day, mainly crickets and roaches but also super worms, horn worms, butter worms, silk worms, etc.  I feed the worms to a lesser degree because crickets and roaches are more nutritious for them. I dust prey items once a week with a calcium w/ vit D3 powder supplement and once a month with a powdered multivitamin supplement.  I feed rodents or ground turkey mixed with cooked eggs and supplements around twice a month.    

Breeding starts when they reach maturity at around two years of age.  They will copulate around the clock for almost a week.  During this time they may or may not be interested in eating.  Females are gravid for 3-4 weeks until laying eggs.  Females will get very large and barely eat right before laying.  She will also lay around looking miserably uncomfortable due to her distended belly.  It is important to make sure the female is well fed a proper diet before and during the time she is gravid.  It takes a lot out of her to develop eggs and if she does not have enough "reserves" she can die while gravid or shortly after. Reserves are protein,water, etc. stored on her body.  The most visible reserve is her tail base.  Prior to breeding this should be thick with no visible bones showing.  Close to laying you will notice this reserve in the tail base being used as bones will slightly become visible.  It is also important to give supplements like calcium, vit D3 and other multivitamins.  Calcium is very important in egg production and if the female does not have enough she can develop metabolic bone disease and die.  When eggs are laid they should be bright white and fully calcified with no areas looking like the shell is thinner.  Eggs not fully calcified are a sign the female has metabolic bone disease and you will need to treat her.  Liquid calcium dosed by weight must be given daily for a month.  During treatment make sure UVB is adaquate (5.0 strength or higher at proper placement to be utilized without causing harm).  Also, powdered calcium should be stopped so that the only calcium supplement is the liquid form.  This prevents accidental overdose.  If you choose to do blood work, normal calcium levels ( for most reptiles) are around 10 for non-breeding animals and twice that much for breeding/egg producing females.  

It would be wise to remove the male just prior to egg laying because once eggs are laid females can become very aggressive protecting the nest.  I have observed my female attacking the male trying to kill him.  Fortunately I removed him right away and his wounds were successfully treated without ill effects.  I have heard of other females killing males defending the nest as well.  They eggs should be removed right after laying.  Gently remove the substrate in the box until they are visible and gently pick them up one by one, placing them directly into the incubation container.  Be careful not to jiggle or rotate eggs if you do not know when they were laid because after 24 hours or so the eggs set and there is a chance of damaging them.  Sometimes it is helpful to mark the top of the egg in marker or pencil with a dot.  This way if they are ever moved from original position while incubating you can put them right, hopefully before damage occurs inside.  Eggs can be incubated in medium like perlite (add water and squeeze out excess before using) or by using a SIM container.  SIM containers have a false floor that you can have raised above water or a damp sponge.  The eggs are placed on top of the false floor to allow maximum air exchange while exposed to humidity.  Sometimes when placing eggs in substrate the substrate can be too wet drowning the eggs, this is what the SIM was created to prevent.  The only issue with the SIM is when eggs are first laid.  The eggs start to look like they are drying out and cave in.  I got very nervous when this happened to me and I ended up putting the eggs on damp substrate.  They plumped back out in a matter of days and look fine.  Another person with the same issue reported that they had left the eggs in the container and after a few weeks the eggs started to plump back out on their own and eventually hatched out.  I have not hatched any eggs yet so we will see what happens.  I have gotten four clutches of eggs, the first my male ate, the second I had a power outage and the eggs died from getting too cold, the third I had incubated for six months and right before they were due to hatch I added too much water to the substrate and they died, the fourth I am incubating right now, three months in.  It takes around six months for eggs to hatch, reports have been 145-210 days.  Incubation temperatures are between 85-87 degrees.  

Babies need similar care to adults with the only differences being a smaller enclosure 
(no smaller than a 20 gallon for one baby), smaller sized prey (no bigger than the width of the head), and basking temperatures.  Babies prefer no higher than 110 degrees, anything higher is too hot.  I learned this with my first tree monitor(he was around 2 months old at the time) as he would hardly bask and when he did he would not stay under for more than a second or two.  As soon as I lowered the temp he starting basking normally. As they grow they need bigger cages.  Around 3-4 months I moved them into a 65 gallon and around six months of age I moved them into their adult enclosure.

If I left anything out or you have any questions let me know.

All the best,