Boscs are a medium size monitor lizard, that normally grow between 3ft and 4.5ft. Some do grow to be over 5ft but those are few and far between.
It is not possible to sex a monitor until they have nearly reached adulthood. This is done by looking at the hemipenal bulges at the base of the tail. A male will have 2 bulges and the female will have 1 in the middle. The other way only works with an adult. You have to look when the lizard is defecating: a male will have 2 long pink hemipenes pop out. A female will not.
The “starter” viv for a baby bosc should be either a 3’x2’x2′, or a 4’x2’x2′. This size viv is suitable for a lizard from hatching to about 20 inches long.
After your baby vivarium, you will need an intermediate size vivarium, either a 6’x2”x2, or a 5”x3x2′. This size vivarium is suitable for a lizard from 18 inches to 32 inches.
Most people say that the minimum vivarium size for a adult bosc is a 6’x3’x3′, but in my opinion the minimum is 8’x3’x3′ for one adult. The ideal Size would be 8’x4’x4′, if not bigger. If you want to keep a pair you will need something like a 10’x4’x4′, or a 8’x5”x5. This size vivarium is for a large monitor, larger than 32 inches.
You are best off using an unplanted vivarium. If you put lots of fake plants and things like that in there the monitor will just wreck them within a matter of minutes. So I would just go for some large logs and rocks, and a large hide. The hide is not necessary if you have deep substrate.
This species requires a lot of space which is where a lot of people go wrong. They don’t understand how big the cute little lizard in the pet shop is going to get.
Your vivariums should have a high sill so you can use a deep substrate. In your baby vivarium you should have a depth of about 3 to 4 inches, for juveniles 8 to 10 inches, and an adult vivarium should have between 1 and 2 foot deep substrate.
One of the things I have found in my research is that wood vivariums with a glass front work a lot better than all glass tanks. The all glass tanks tend to stress the monitor out and don’t hold humidity as well.
There are a lot of different things that you can use such as eco-earth, cypress mulch, or orchard bark. Most people say that a sand soil mix (best just to use garden centre variety play sand and plain potting soil) works the best but basically you just need something that will hold humidity and will allow your lizard to dig.
The temperatures in your vivarium are pretty simple. You will need a hot end, temperatures of around 95f (35c). The cool end should be around 85f (29c). You should also have a basking spot with temperatures (that is, the surface temperature under the heat lights not the air temperature — you will need an infrared temperature gun to measure it) should be 130f(54c). It does sound hot but they will bask in even hotter temperatures. I have heard of them basking up to 150f, but I wouldn’t go that hot as you might end up burning your lizard.
To get the basking temperature right without overheating the hot end, you are best off using a bank of low wattage halogen lights instead of one high wattage reptile light. In your baby monitor’s vivarium I would use 2 or 3 R80 60w halogen bulbs. In your juvenile’s vivarium I would use two par38 80w outdoor flood bulbs. In your adult’s vivarium I would use three par38 80w outdoor flood bulbs.
All of your heating should be controlled by a thermostat. For your heat lights you will need to get a dimmer (rheostat) to control your temps.
If you live in a colder part of the world you might have to use something for background heating. In your smaller vivarium I would use a 60w or 75w ceramic heater. In the bigger vivariums a tube heater will work best and don’t forget that you will need a thermostat.
Everyone has a different opinion about UV. I have always used UV with my bosc, but I do know a lot of people that don’t use UV. They don’t have any problems with their lizards, but as I have always said “It’s not going to hurt. So you may as well give it to them”. I use a 4ft 10.0 uv tube (the exo-terra one) in my monitor’s viv.
The humidity in your viv should be between 50 and 65%. If you are using the right kind of substrate there should be no problems getting it up to that. The deeper the substrate the easer you will find it to keep up the humidity. All you should need to do is spray the whole vivarium down 3 or 4 times a week, and maybe add some water to the substrate a couple of times a month. You should just do this when the substrate starts to look dry.
You should have a very large water bowl big enough for the lizard to get into and bathe. The water should be changed for fresh warm water ever day.
Again this is where a lot of people go wrong. It is common practices to feed bosc’s on an all rodent diet. This is not good for them. When they are young they should be on a 100% invertebrate diet. Then when they get older you can introduce things like raw meat, fish, and a very occasional mouse or rat.
You should be feeding your young monitor every day on 5 or 6 appropriate sized insects. Either 3rd or 4th stage locusts, large crickets, small roaches, and super worms.
I would feed a juvenile every other day mainly on insects 5th stage or adult locusts, medium roaches up to about 10 of either super worms and snails. Then maybe once a week I would give it either a couple of medium/large mice, rat pups/fluffs or turkey mince, chopped up chicken, chopped up fish or prawns.
Your adult monitor should be fed every 3rd or 4th day, 2 feeds. I would give it a large number of insects maybe 25 to 30 adult locusts or adult roaches. Then for a 3rd feeding give it a large bowl of raw meat or fish. Maybe once a month as a treat you can give your monitor 2 medium rats. Other things you can use as a treat are things like African land snails, and scrambled or boiled eggs.
This is just a guide and will vary from monitor to monitor. So you will have to make a decision by looking at you monitor as to how much you need to feed it. Remember that these monitors are meant to be well built but not fat.
Food is one of the main factors when you are thinking of getting one of these lizards. When they are adults they cost a lot to feed and I mean a lot. So if you have any doubt in your mind that you can afford to feed an adult monitor you shouldn’t get one.
There are two main ways of taming. There is the hands on approach, and the hands off approach. Although tame is the wrong word to use. Tolerant is a better word. You have to remember that monitors are not like a cat or a dog, but with a lot of time and work boscs will become tolerant enough for you to be able to handle your lizard. Some do even get to the point that they enjoy interaction with people.
Hands on approach
With this way of doing things there is a risk that your monitor will just be scared of you, and in that case it will not become tolerant. To start off with, you need to leave your lizard to settle in for a couple of weeks. Then you start off with a bit of handling, just short 5 minute sessions a couple of times a day. Then work up to 10 minutes at a time 3 or 4 times a day and so on. The main thing with this approach is persistence. Yes you are going to get bitten, but you just have to put up with it and keep trying.
Hands off approach
This way of doing things takes a long time, but has a lot better result than the hands on approach. You are a lot less likely to scare your lizard doing it this way. So all in all this is the best way of doing things.
To start it is very similar to the other way of doing things: just leave the lizard to its own devices for at least a couple of weeks if not a month, only going in to the vivarium when you have to do your daily maintenance such as changing water, putting the food in, cleaning and other things like that. Don’t be surprised if your lizard runs and hides when you go into his vivarium at first. After awhile he will stop running and hiding. At that point you can start by trying feeding with a set of tongs, instead of just putting the food in the vivarium. Then you can start putting your hand near it when it’s up and about in the vivarium. When it stops running when you do that, start trying to touch it on the head. When it stops running when you touch it, start picking it up just for a short time, maybe 5 minutes at a time. At the same time keep up with the tong feeding. In the end you should end up with a nice tolerant monitor.
Neither of these techniques is a sur- fire way to tame a monitor. These are just the ways I would recommend.
This will not happen overnight. It will probably take at least 6 to 8 months for it to get to a point where you can work with them with no problems.
You will see a lot of vids on youtube with people that claim their monitors are tame. The truth is that most of those monitors are not kept properly, or in suitable tanks, or they are not kept at the right temperature. So they appear tame, when in fact they are very ill. Another reason that they may seem tame is if the monitor has been mistreated and the monitor is scared. This will lead to stress and in turn it will shorten the monitor’s life significantly.
This is not something I have any experience with and I would not recommend it as there are lots of boscs in captivity and not enough people that know how to look after them but if you do want to breed them this is the information I have found. When people do breed them it is best to keep then in a trio of 1 male and 2 females. There is no way to get them to definitely breed but if you do get eggs the incubator should be at 87f (30c) and it should take between 130 and 170 days
A Few Words
Boscs are a class lizard, and do make really good pets if you have the time, money and space to keep one. The main problem with these lizards is that people see them in the pet shop when they are small, cute and cheap. They don’t realise how quickly this little lizard is going to get big, and how much space it is going to need. So a lot of these lizards end up in rescue centres. If you are thinking of getting one, you need to make sure you know what you are letting yourself in for.