Housing: These lizards present two significant problems to the average herpetoculturists when it comes to housing:
• They reach a significant length
• They are highly arboreal
An adult crocodile monitor will require a tall, room sized enclosure, a good sized greenhouse would be preferable. These lizards spend a great deal of their time in the upper canopies of forests and would require a cage with an estimated measurement measuring of around 20x20x35. If you do decide to get one of these, make sure that it has a great deal to climb on as they spend very little time on the ground in the wild. They should probably be able to get from one side of the cage to the other without ever setting claw on the ground. They should also have hiding areas both on and off the ground.
Heating, Lighting and Humidity: The temperature in the basking zone should be about 90° or 95° F but a gradient should be provided down to about 80° F with humidity above 70%. With temperature, the safest way to find out your lizard’s preferred temperature is to see where it spends most of its time. If it is constantly basking, your cage is too cold; and if it is constantly in the cool area, the cage is too hot.
Feeding: Being mostly arboreal this lizards should not be fed large meals at a time. They should be fed about 4 days per week with a diet mainly consisting of large insects, small mammals like frozen rats, frozen feeder birds, eggs, and other lizards. As they grow, you will have to feed them increasingly large meals such as
feeder chickens, etc... One quick note, these lizards have been referred to as 'lazy' when it comes to their feeding, meaning they will not expend great amounts of energy subduing large prey.
If you do feed your monitor large prey, you should feed them pre-killed or frozen feeders, as you eliminate the possibility of the prey fighting back and, believe it or not, doing some real damage. This method is also much more economical if you buy frozen rodents or other feeing animals in bulk and store them.
General: These lizards are definitely not recommended for anyone without a great deal of time and money to sink into them. Being so highly arboreal, they require perhaps the largest cage size of any monitor, including Komodos. These lizards are like, larger, meaner, and significantly more dangerous versions of the Green Tree Monitor (Varanus prasinus). They tend to remain similarly wary throughout their lives and since their max size is so great, they are harder to tame.
On a positive note, of their potential 11 feet or so, about 200% of it is tail, which can be a highly dangerous weapon which they will use, but this also means that you won't have a lizard of nearly the bulk one would expect.
Finally, do not to mix these up with the water monitor (Varanus salvator) which commonly happens due to the similarity of specific names. They do not require nearly the aquatic habitat of water monitors but do need a great deal more space.