What should Varanid husbandry practices be like?

[monitorlizard]

After reading various threads about nesting options for monitors in captivity as well as diet in captivity, I began to wonder what should general husbandry practices be like.

-Should we mimic the wild to the closest degree? Using the largest enclosure possible and providing a very deep substrate for burrowing, nesting, etc. Feeding a multitude of prey items that would be found normally in the monitor's natural habitat or at least species similar. Keeping the animals in (for lack of a better term) colonies or pairs similar to the groups of animals normally found in the wild. Providing many temperature gradients and fluctuations withing the enclosure mimicking the rise and set of the sun as will as replicating the annual climate changes the occur within the animal's natural habitat?

-Should we do everything for then animal, providing an almost hospital like environment. Doing this by keeping the animal on a sterile substrate, providing prepared food items loaded with vitamin and mineral supplements, providing only two temperatures within the cage(one with a higher temperature for digestion, and a lower temperature to provide stable conditions that will not influence the monitor internally). Only giving the animal a nest box when the female is gravid.

-Should we do some kind of combination of the two? Perhaps providing food items that are not necessarily found in their natural habitat, but rather are nutritionally the best. Together with that providing a habitat that is similar to their habitat in the wild.

[Grendel]

I believe in the first option, and strongly reject the second.

[Aanayab1]

I am still fairly new to the monitors world. I follow the mimic style husbandry. It is a very hard task due to the lack of credible information on the subject. The amount of research needed is quite intense. I think the important thing is to be able to pass on the information needed on sites like this, drama free (as much as possible) so people will not just wing it out of frustration... This site is the first I have found where the drama is at a minimum and I love it!

[Pirarucu]

I believe in the first option, and strongly reject the second.This exactly.

[Akuma223]

First option no contest.

[crocdoc]

I don't think there are hard and fast rules. Clearly a sterile environment isn't going to work, but beyond that whether or not you try to emulate the wild depends on the situation and what it is you are trying to emulate (food, nesting etc). Sometimes trying to emulate the wild is good, sometimes it works better if you don't try to emulate the wild and I can think of some very good examples of this, but for now I'd like to ask you a question regarding one of your points:

-Should we mimic the wild to the closest degree? ... Keeping the animals in (for lack of a better term) colonies or pairs similar to the groups of animals normally found in the wild.
Out of curiosity, where did you get the information that they live in colonies, pairs or groups in the wild?

[smy_749]

I believe native Arizonian Tuscon Ackies and Phoenix Kimberly rock monitors were observed in their natural habitat (basking stacks inside metal troughs and custom built fiberglass enclosures with pool liner tops) in groups of 3 or more.

[crocdoc]

:)

...you're onto something there.

[Pirarucu]

I should refine my stance a bit. I believe that optimal natural conditions should be replicated. A sunny day during the wet season should be the goal, not a cloudy day during the dry season. That environment should be established as a base to work off of, then modifications should be made according to the behavior of the animal. (e.g. if the monitor spends more than a few minutes at a time on it's basking spot, raise the temps. If it stays in the cooler areas, lower the temps, etc.)
This is referring to the environment. Diet does not necessarily need to be what they eat in the wild, as long as it is healthy, whole prey.

[smy_749]

I should refine my stance a bit. I believe that optimal natural conditions should be replicated. A sunny day during the wet season should be the goal, not a cloudy day during the dry season. That environment should be established as a base to work off of, then modifications should be made according to the behavior of the animal. (e.g. if the monitor spends more than a few minutes at a time on it's basking spot, raise the temps. If it stays in the cooler areas, lower the temps, etc.)
This is referring to the environment. Diet does not necessarily need to be what they eat in the wild, as long as it is healthy, whole prey.

Do you guys find that preferred temps for savannah/grassland/desert species are the same for rainforest/tropical species with lots of canopy cover?

[Pirarucu]

Do you guys find that preferred temps for savannah/grassland/desert species are the same for rainforest/tropical species with lots of canopy cover?From what I know yes, they should use around the same temps, though some rainforest monitors won't use temps on the high end of what grassland species will use. Ultimately it comes down to listening to what your monitor is trying to say.

[monitorlizard]

I don't think there are hard and fast rules. Clearly a sterile environment isn't going to work, but beyond that whether or not you try to emulate the wild depends on the situation and what it is you are trying to emulate (food, nesting etc). Sometimes trying to emulate the wild is good, sometimes it works better if you don't try to emulate the wild and I can think of some very good examples of this, but for now I'd like to ask you a question regarding one of your points:


Out of curiosity, where did you get the information that they live in colonies, pairs or groups in the wild?
Water Monitors live in fairly large groups. The same might apply to Komodo Dragons, though it appears they are seen only in groups during breeding and feeding. Many monitors probably don't live in groups now when I think about it though.
http://varanidae.org/Vol_2_No_1.pdf
(Varanus Salvator)

http://varanidae.org/4-4.pdf
(Ackies)

And I believe Nile Monitores live in "groups"

[crocdoc]

Water Monitors live in fairly large groups. http://varanidae.org/Vol_2_No_1.pdf
(Varanus Salvator)

There isn't any article in that issue of Biawak mentioning salvator living in groups?

Unless you're referring to the photograph? The caption offers a hint:
"Varanus salvator. Salang Village, Tioman Island, Malaysia."

Be very careful about making assumptions on the basis of photographs.

When you see a photo taken in a village, with several monitors in the shallows looking in the same direction, my money is that, out of frame, there's a fisherman with scraps who has been feeding them on a regular basis.

Many large monitors can be found in concentrations near man-made artificial food sources, such as garbage tips, parks, picnic areas, villages... you name it. They will also gather around carrion. However, this doesn't classify them as living in groups or colonies, for they are there for the food, not each other.

Varanus salvator isn't by nature a colony or group animal.

A solitary Varanus salvator near Singapore. Although I've got very limited experience with this species in the wild, the ones I saw were either concentrated near human habitation or solitary when out in the forest/mangroves, away from humans.
http://www.pbase.com/crocdoc/image/148303134.jpg

The same might apply to Komodo Dragons, though it appears they are seen only in groups during breeding and feeding.

Komodo dragons are solitary. They'll gather around carrion. Photographs you see of them lying around in groups are invariably taken near the ranger stations on Rinca and Komodo islands, where the rangers throw out their food scraps (and the buildings offer shade from the heat).

Solitary dragon out on the savannah.
http://www.pbase.com/crocdoc/image/97999492.jpg

Dragon feeding on scraps next to the rangers' kitchen on Komodo.
http://www.pbase.com/crocdoc/image/98297507.jpg

Young dragon moving around near the ranger station on Rinca. The animal's posture indicates the unease with which it hangs around other dragons - its arched neck and puffed throat and abdomen are a sign of threat. Almost all of the smaller dragons did this every time they got up to move.
http://www.pbase.com/crocdoc/image/98445524.jpg

Big male dragon doing the same, on Komodo island. There was another big male nearby and, although they occasional were lying near each other nonplussed, they spent a lot of time hissing and almost scrapping with each other.
http://www.pbase.com/crocdoc/image/98000794.jpg

\
http://varanidae.org/4-4.pdf
(Ackies)

The article on two ackies mating in the wild? Mating isn't a sign of living in colonies or groups, either. All monitors must mate, so males and females will get together for that.

However, to keep it on topic, this is one of those areas where it's best not to emulate the wild, for if one wants to breed monitors in captivity it's best to keep them together in pairs. The reasoning behind this is as follows: In the wild, males and females will pair up for a short period each year. That pairing starts when the female is reproductively receptive and they approach each other carefully. The good thing about the wild is that if things don't work out, there's unlimited space in which they can run away.

In captivity, putting two animals together in an enclosure of limited size has its dangers. If they don't get along, there's no room to get away and that's when bad injuries (or even deaths) occur. Consequently, you don't want to be guessing when the female is going to be receptive and constantly reintroducing the pair over and over again. If they get along, then leave them together and it takes away the dangers of reintroduction.

There are 'some' people (no names mentioned) who have made the assumption that since captive monitors seem to get along so well, they must be social animals in the wild. This is not the case. I've seen thousands of monitors in the wild of at least a dozen different species. They've all been solitary, with the exceptions of Komodo dragons around ranger stations, water monitors around human food sources and lace monitors around picnic grounds. In those instances, for all three of those species the interactions between the individuals was anything but social and was almost always antagonistic.

[monitorlizard]

I should refine my stance a bit. I believe that optimal natural conditions should be replicated. A sunny day during the wet season should be the goal, not a cloudy day during the dry season. That environment should be established as a base to work off of, then modifications should be made according to the behavior of the animal. (e.g. if the monitor spends more than a few minutes at a time on it's basking spot, raise the temps. If it stays in the cooler areas, lower the temps, etc.)
This is referring to the environment. Diet does not necessarily need to be what they eat in the wild, as long as it is healthy, whole prey.
And changes to induce breeding?

[Pirarucu]

And changes to induce breeding?In a suitable environment, most monitors will breed without a need to replicate a "breeding season".

[monitorlizard]

What about the use of nest boxes?
I seen(what I believe to be) people with cages that have a very shallow substrate but have a nest box. Would that suffice, or is that completely unacceptable? Crocdoc, I have seen you use nest boxes, how deep is your substrate?

[Pirarucu]

What about the use of nest boxes?
I seen(what I believe to be) people with cages that have a very shallow substrate but have a nest box. Would that suffice, or is that completely unacceptable? Crocdoc, I have seen you use nest boxes, how deep is your substrate?Some species, such as varius and rosenbergi, nest exclusively in structures like termite mounds, and so should be provided with something that replicates this for nesting. Some species usually don't burrow and therefore do not need the deep substrate throughout their cage.

I am in favor of offering dirt through the whole cage and offering nest boxes. Let the varanids decide what they need or don't need.

[monitorlizard]

What about the size of the cage? Varanids have huge territories in the wild. Now for the most part we obviously cannot replicate that, but how big do you think the minimum size for a cage should be.
I understand the idea of the length of the cage being twice the lizard's length with a width and height that are the same length as the lizard, but to a lizard from the wild that is only allowing the lizard to take a couple steps forward and then turn around. This obviously isn't applied to lizards under two feet, because they are give four plus foot cages. Why not apply the same to larger lizards? Rather then twice the length of the lizard for the length of the cage how about three times and instead of the length of lizard for the height and width why not twice the length? Or is that just not practical?

I think I understand FR when he said that an arboreal cage cannot be achieved in captivity unless you use an entire tree. When I see people with arboreal varanid enclosures I normally see shallow substrate with a bunch of four to six foot logs placed vertically to mimic a tree in the wild. But in the wild that would be just the base of the tree. Arboreal Varanids use not only the base but also the canopy fifty plus feet off the ground. Rather then bother with a substrate and mimic the base, how about trying to mimic the canopy by having the main structure of the enclosure logs, with nest boxes in the trees that resemble hollows frequently found in trees or termite nests that a monitor would lay its eggs in. Since the monitor is arboreal it wouldn't want to burrow.

[crocdoc]

I am in favor of offering dirt through the whole cage and offering nest boxes. Let the varanids decide what they need or don't need.

Bingo. I agree wholeheartedly.

Crocdoc, I have seen you use nest boxes, how deep is your substrate?
I guess you didn't read that exchange on KS ;) (I'm teasing, as I know just how long it was).

The long and short of it is this: As Pirarucu has said, some species are termite mound nesters in the wild and it is my opinion (based on my own experience as well as the experience of many other keepers) that these species nest particularly well in nest boxes. I think offering them a choice is important, but for those species a nest box should be one of the choices offered.

In answer to your question regarding substrate depth in my enclosure - I used to religiously keep it very deep, but the female has never nested in it (she's done test digs, but never followed through). Now the depth varies depending on how frequently I top it up. It's still important for retaining humidity, but not important for nesting with my animals.


I think I understand FR when he said that an arboreal cage cannot be achieved in captivity unless you use an entire tree.
In a sense he's right, but the reality is still that some species will do better in a vertical enclosure than others. I don't think many monitors (other than tree monitors) are likely canopy users, but a lot of species do use trees for escape/security, for foraging and for basking, and these can be achieved in a tall enclosure that's not necessarily tree height. I know from experience, for example, that young, nervous lace monitors do much better in an enclosure in which they can get above my head height.

Even my adult lace monitors like to rest on the very short trees in my enclosure in the same way wild monitors do - vertically.

Alex, my male at home.
http://www.pbase.com/crocdoc/image/85656620.jpg

Wild lace monitor.
http://www.pbase.com/crocdoc/image/141569263.jpg

Alex, at home.
http://www.pbase.com/crocdoc/image/85656615.jpg

Wild lace monitor I saw three days ago.
http://www.pbase.com/crocdoc/image/149297543.jpg

[smy_749]

How do the varius eggs survive inside the termite enclosure? Termites don't eat away at or attack the eggs? Just curious...But I'm assuming after the eggs are laid inside, and the termites close it off again, it makes for a nice moist incubator lol Also, is there any way to recreate a termite mound type structure in your enclosure with a specific type of dirt (minus the termites) ? That would be pretty cool haha

Also we all know you can't achieve a 100 ft + canopy in your house, or anywhere for that matter unless you created an 10 story building with a tree in the middle. But everyone understands that saying arboreal when it comes to enclosures, just means if you have to choose between a 8 x 4 and a 4 x 8 , you would obviously choose 8 x 4 for a species which tends to be terrestrial, and 4 x 8 for a species which tends to enjoy being off the ground because it is MORE aboreally oriented. Its just that when I said the A word (its forbidden in some forums), some people assumed I thought it would be a sufficient substitute/equivalent for a rain forest canopy environment which anyone with sound intellect would realize is not what I meant :S

Oh...and I never get sick of those varius pics. The last 2 look very different, the smaller bottom one seems to have a longer skinnier snout, maybe its just the angle. Is that hanging position on the tree strenuous on the muscles, or do they just let the claws do the work and sort of dangle there?

[Pirarucu]

How do the varius eggs survive inside the termite enclosure? Termites don't eat away at or attack the eggs? Just curious...But I'm assuming after the eggs are laid inside, and the termites close it off again, it makes for a nice moist incubator lol Also, is there any way to recreate a termite mound type structure in your enclosure with a specific type of dirt (minus the termites) ? That would be pretty cool haha

Also we all know you can't achieve a 100 ft + canopy in your house, or anywhere for that matter unless you created an 10 story building with a tree in the middle. But everyone understands that saying arboreal when it comes to enclosures, just means if you have to choose between a 8 x 4 and a 4 x 8 , you would obviously choose 8 x 4 for a species which tends to be terrestrial, and 4 x 8 for a species which tends to enjoy being off the ground because it is MORE aboreally oriented. Its just that when I said the A word (its forbidden in some forums), some people assumed I thought it would be a sufficient substitute/equivalent for a rain forest canopy environment which anyone with sound intellect would realize is not what I meant :S

Oh...and I never get sick of those varius pics. The last 2 look very different, the smaller bottom one seems to have a longer skinnier snout, maybe its just the angle. Is that hanging position on the tree strenuous on the muscles, or do they just let the claws do the work and sort of dangle there?Correct me if I'm wrong, but I believe he uses coconut husk/fibers in the heated nest box after experimenting with different materials.
In the wild, termites would not bother the eggs as they are too big to shift and are not food. They treat them like rocks that appeared in their mound.

As for the ten story building.. Moody Gardens has done just that, with a lot more than just one tree, LOL. The pyramid is ten stories tall.
The Croc Monitor can climb thirty or forty feet up in his enclosure if he wants to, though he usually doesn't.

[smy_749]

Correct me if I'm wrong, but I believe he uses coconut husk/fibers in the heated nest box after experimenting with different materials.
In the wild, termites would not bother the eggs as they are too big to shift and are not food. They treat them like rocks that appeared in their mound.

As for the ten story building.. Moody Gardens has done just that, with a lot more than just one tree, LOL. The pyramid is ten stories tall.
The Croc Monitor can climb thirty or forty feet up in his enclosure if he wants to, though he usually doesn't.

Ah ok makes sense. Although if they carry half the strength ants do, (Idk much about termites), you'd be suprised what a few thousand can move around/kill.

Do you have any pics of the entire enclosure? Is it a private place or a zoo?

[DeadlyDesires]

I believe in the first option, and strongly reject the second.


most deff!

[crocdoc]

How do the varius eggs survive inside the termite enclosure? Termites don't eat away at or attack the eggs? Just curious...But I'm assuming after the eggs are laid inside, and the termites close it off again, it makes for a nice moist incubator
The termites seal off the enclosure but don't harm the eggs. The reason monitors use these mounds is because they are moist and warm - perfect incubators - and remain warm all winter. It's no coincidence that the two species of monitor in Australia with the southernmost distributions both nest in termite mounds and both have eggs that overwinter.

Also, is there any way to recreate a termite mound type structure in your enclosure with a specific type of dirt (minus the termites) ? That would be pretty cool haha
Yes, I've been using a nest box that mimics the conditions of a termite mound, for many years. It's worked at treat.


The last 2 look very different, the smaller bottom one seems to have a longer skinnier snout, maybe its just the angle.
Mostly angle and age.

Is that hanging position on the tree strenuous on the muscles, or do they just let the claws do the work and sort of dangle there?
The latter. They dangle. When they are high up in a tree and want to stay there for a while (for example, to avoid a predator), they let the body hang and all of the limbs go straight, so the claws and tendons do the work rather than the muscles.

If you look closely at that bottom photograph, though, you'll notice that the tree the monitor is on is smooth and barkless. Only a monitor with claws sharp as fish hooks can climb that, but they have no issue at all.

Here's an example of a wild monitor hanging for the duration, with arms and legs straight
http://www.pbase.com/crocdoc/image/78435254.jpg

[smy_749]

Thats probably the best example you can show someone to give an idea of how sharp the claws are, Smooth surfaces, effortlessly hanging out, are you sure that last pic is not a gecko? :-P hahaha

I posted this question on another thread but don't remember which one, I'm posting too much and getting all excited...I read on a research paper that murrindidi sent me that griseus have hatchlings which hatch before the cold season, and stay underground, first emerging in the spring. Is this common in monitors? I found it strange being that typically in nature, animals are born in optimal growing/feeding season.(obviously winter is not the optimal season, being that they never emerge, or is it just outdated info..20+ years is a long time)

"Hatching the young-of-the-year takes place in burrows at the end of August and in September. Although some findings of hatchlings at the end of August and in September were reported (Ataev, 1985;Tsellarius et al., 1991), they appear, as a rule, at the surface only the next spring (Bogdanov,1986).

[crocdoc]

If that is the case with griseus (I don't know their natural history well enough to verify that), that would make sense for a monitor that lives fairly far north, where the winters are cold.

1. Monitor eggs have long incubation periods.
2. Monitor eggs require fairly warm temperatures for incubation (30C).
3. Baby monitors are better at seeking shelter and coping with cold than monitor eggs would be.

Imagine a pair of monitors mating in spring or early summer. The female lays eggs a month later and the eggs must incubate for several months before hatching. By then it's late summer or early autumn. One biological 'choice' would be to have a longer incubation so that the hatchlings emerge in spring, but in the places griseus are found the ground wouldn't be warm enough for eggs mid-winter this and there probably aren't any termite mounds in which to nest. Hatchlings, though, can seek shelter for the winter and can cope with quite low temperatures, lower than the eggs would cope with.

Something similar happens to livebearing reptiles in cold climates, like garter snakes in Canada. By the time the babies are born it is late summer and they may not get many meals in before heading underground for winter. They sometimes go straight down shorty after birth, without any meals at all.