Bioactive Enclosures for Spilotes pullatus

This article is about changing an existing enclosure for Tiger Rat Snakes (Spilotes pullatus) into a themed bio active enclosure and the practical experience with maintaining it.

The original setup of the enclosure

I got my first Spilotes pullatus in 2009, a German captive bred male from 2007. It was obvious that the temporary enclosure I kept him in was too small to keep such an active snake for an extended period of time. Due to the spatial restrictions of my home it took some time to plan an enclosure which would be an attractive addition to my living room as well as a more than just sufficient new home for my still growing Spilotes. With the help of a friend we came to a really nice solution in the end, but it took him some additional time to figure out how to build this particular brainstorm of mine. The enclosure was finished in 2011. 

The enclosure is 250 x 90 x 190 cm (ca 8 x 3 x 6 ft) length x depth x height, I used two 70W metal halide lamps for ambient lighting and heating and in addition another 70W metal halide light which also emits UVB light. I have also two RHP on a thermostat for additional heating, but since they never had to do anything they are offline since 2012.

I used living plants from the outset, but I chose plants for their sturdiness and the survivability in a heavily used environment. So I used nothing imaginative but the always present pothos (Epipremnum pinnatum) and (Scindapsus pictus) regardless of the origin of the plants. I also used some smaller Epiphytic plants like bromeliads that, unfortunately, didn’t last more than a few weeks.

In 2015, I was still searching for a female for my male when a friend suggested loaning his pair to me for two years since he could not keep them any longer due to some extensive repairs needed on his home. I could try to get my male (or his) to breed with the female and he had enough time to do his repairs. I got his pair in February 2015. Unfortunately, my male died a short time later because of an inflammation in his bowls (gastroenteritis) which didn’t show any symptoms until a few hours before his death, so I had only the loaned pair left.

In September 2015, I got a WC female from French Guiana and in June 2016 another WC pair also from French Guiana. The first female was kept together with the pair from my friend and I planned to keep the new pair in quarantine until he would get his snakes back (which was supposedly a little more than 6 months, so just long enough for WC animals). A few months later, my friend told me that he was unable to take his snakes back, because the repairs proved to be more of a rebuilding of the entire house and he had neither the time nor the resources to do this at that time. He offered to sell me the snakes, otherwise he would give them to a zoo who already kept Spilotes. I was really tempted to buy the female but decided against it in the end because my enclosure was OK for three snakes. Another female might have pushed it and I didn’t have enough room for another large enclosure. So he made the arrangements to hand them over to the zoo. They are now in the Zoo of Dortmund, if you are in the vicinity of the city of Dortmund (eg visiting the Terraristika expo in Hamm) you could visit the Zoo and the Amazon house there to have a look at the pair I kept for more than 2 and a half years.

A new beginning

Since the enclosure needed an overhaul, some of the plants had been in there since the beginning in 2011 (and it showed) I decided to do it a different way this time. I wanted to build an enclosure which is completely bio active and themed as a Central / South American habitat. The basic setup remained the same, the branches and cork tubes were the same as before. I only chose plants from this region. I added Xaxim panels for the backside of my enclosure as additional foothold for the climbing plants (and the climbing snakes) as well as added a special substrate to the sidewall. It consisted of some kind of glue and substrate with seeds and spores in it. When it dries out and becomes solid you begin to water it and after some time it is supposed to spawn moss and all kinds of different plants to create a living sidewall. However, this substrate is originally used in smaller enclosures for dart frogs, so I found it doesn’t work on large walls, it broke down after some time and covers no part of the ground.

The ground consists now of two layers of pebble stones as a drainage layer and on top of this a mix of soil and sand. The complete substrate is about 25 cm (10 inches) deep.

I originally used the following plants

• 1 x Dieffenbachia seguine
• 1 x Monstera deliciosa
• 1 x Monstera acuminata
• 3 x Marcgravia sintenisii
• 1 x Cissus amazonica
• 1 x Begonia thelmae
• 1 x Begonia microsperma
• 1 x Mimosa pudica
• 1 x Pilea involucrate
• 1 x Pilea sp. “Panama“
• 1 x Philodendron camposportoanum
• 1 x Philodendron sp. “Französisch Guyana”
• 1 x Philodendron scandens
• 1 x Nanodes/Epidendrum porpax

I left the Dieffenbachia and Monstera deliciosa in their pots to give them some additional support and enough depth for their roots. I left the Philodendron scandens in it’s pot as well and put the pot in the cork tube centered in the enclosure right behind the Dieffenbachia, creating a level resting place right under one of the UVB lamps. I did the same with the Monstera acuminate with the second cork tube in the right corner. The plant pots have the same diameter as the inner diameter of the cork tubes. The other plants were planted directly into the substrate. 

The enclosure was finished at the beginning of September 2017, the first female Spilotes moved in on September 7th, followed by the second female and the male one day later.

I added two breeding colonies of isopods and five millipedes as cleaning crew (the millipedes are from Madagascar, there were simply no South or Central American species available).

In order to provide enough light for the plants on the ground I added another UVB emitting 70W metal halide light, so the enclosure runs with a total of 280W of lighting. 

The new model enclosure is now in use for nearly 2.5 years, occupied by a large male (ca 240 cm / 8 ft in length and weighs about 3.1 kg) and a smaller female (about 200 cm / between 6 and 7 ft and weighs about 1.0 kg). The second female died a year ago, a necropsy showed an small slug egg which had caused a sepsis eventually.

The smaller plants didn’t make it, but I expected this from the beginning, since most of the plants were complete unknowns care wise. Surprisingly most did rather well for a while, especially the large plants like the Dieffenbachia seguine and Monstera deliciosa. Both have lost some leaves due to heavy use, but they have grown more leaves to replace the lost ones. The smaller plants were crushed by the snakes eventually, they simply could not replenish the lost substance fast enough. I added other plants to replace them, currently I use 3 Fittonia sp., a Philodendron scandens and 2 different Monstera at ground level. These plants are now in place for ca. 18 months and it seems that they can handle the stress. 

Overview of the current enclosure

Heating with four 70W lights and the horizontal branches offers basking and resting spots in different heights and provides a vertical thermal gradient. There are several different microhabitats in the enclosure the snakes can choose for basking, resting or hiding. 

This is another picture to provide an overview of the whole enclosure. The following schematic shows the placement of the four lights on top of the enclosure.

The liana branches supporting the Monstera deliciosa are directly in the flood area of one of my UV emitting bulbs, creating a hot spot of ca 25°C / 77°F and providing UVB (UVB index 1.0). An additional bonus is the light color which is in the right spectrum for the plant’s photosynthesis. This spot is used by both snakes, the female and the male, even though it is a little more difficult for the male to get enough support to stay there due to his larger size and weight. 

The situation on the vertical cork tube in the center rear of the enclosure is the same, it is on the fringe of the left UVB bulb and is covered by most of the output of the second UVB bulb, the temperature on the surface of the cork tube is 32°C / 90°F, the UVB index is 1.2. This resting place is used by all of my Spilotes, sometimes by all of them at the same time. 

The second cork tube in the right corner is not directly lit, it is a little shady and gets only stray light from the center UVB bulb. With 27°C / 81°F it is slightly cooler, the UVB index is 0.7. It is also used by all snakes, but most frequently by the female, she will stay here most of the time. 

This is the situation between the two cork tubes at the right side at ground level. There is still some light from two bulbs getting there, but the temperatures are lower, about 23°C / 73°F and an UVB index of 0.1, so there is only a little UVB reaching ground level. Under the leaves of the Dieffenbachia and within the cork tubes there is no measurable UVB. At ground level at the left side the situation is similar, temperature is about 23°C / 73°F and an UVB index of 0.2. 

I spray luke warm water with a hand sprayer once a day, 6 days per week, with one “dry” day. I spray water at every plant and leaf as well as on the substrate. If a snake is somewhere outside I spray water directly on the snake and if it is starting to drink I continue to spray until it stops. I usually spray about 2.0 – 2.5 Liters of water per day. This creates a constant humidity of close to 100%, dropping during the dry day to 80% – 85%. The substrate is slightly moist but not wet.

So the snakes can choose different microhabitats in different heights, different temperatures and different exposure to (UVB) light, ranging from temperatures between 23° C and 32° C (73° F and 90° F) and an UVB index between 0.0 and 1.2. The humidity ranges from 100 % after spraying and 85 % 24 hours later before next spraying.

The large water bowl in the enclosure is rarely used, sometimes the snakes will drink from it after having eaten something, but they prefer to drink water droplets after spraying. Now, in 10 years of continuous keeping at least one Spilotes pullatus, I have seen exactly one using the water bowl to bathe in for two days, the female didn’t do it before and never did it again. When I saw her in the water bowl it was so completely out of character that I checked her later, but there was no obvious reason (like stuck shed, mites, etc).

The cleaning crew is not up to the task of removing the feces fast enough to avoid the smell nuisance, so I remove the feces (but leave the urates) since the enclosure is in my living room. Sometimes this proofs to be a difficult task because finding the feces is rather more difficult than smelling it.

Behavior of the snakes

The female settled in within a week or so. Since then she is active or resting on the cork tubes or the liana branches. The big male took much longer. During his first four weeks in the new enclosure, he stayed in one of the cork tubes out of sight most of the time and if he was outside he would go into hiding as soon as he spotted me near the enclosure. Today he has settled in as well, but he is still more wary and is always cautious when I open the enclosure. 

Both of them will bask under one of the UVB lights for some time, this can be a few minutes or several hours, usually starting in the late morning til early afternoon. The female will spend most of her time on top of the right cork tube, the male chooses to rest on ground level quite often. 

When basking they might inflate their neck to create an even larger surface and probably to warm the air in their throat, you can see them keeping the air in their throat for some time and then taking a deep breath, so this might be a way to warm the inside of the snake more efficiently.

There is a significant size difference between male and female. The male is considerably longer (240 cm) and heavier (3.1 kg) than the female (200 cm / 1.0 kg). However, this size difference doesn’t cause any problems when keeping a pair or even a group of them in the same enclosure.

The snakes are usually fed once every week or every second week, depending on the food size and amount the snakes ate the last meal. The female usually eats one or two small rats (30 – 60 g) or two to three day old chicken. The male eats two medium rats (100 – 150 g) or up to 4 day old chicken per meal. I feed at least three meals with rats before I offer a mixed meal of rats and chicken (one rat, one or two chicken) or a chicken only meal. This reflects the findings of a field study from the Atlantic Forest of Southeastern Brazil. 

The defensiveness the snakes showed when they were still in the smaller quarantine enclosure had ceased within a short period of time. During spraying or maintenance the snakes watch me and start to flick their tongue if I come too close for comfort but they usually don’t bother to rattle their tail or even inflate their neck.

Cohabitation

Keeping Spilotes pullatus in pairs or groups of one male and two females is no problem. Females don’t show any territorial behavior against each other. I never experienced any aggressive behavior between males and females. Obviously feedings have to be watched, but in my enclosure, it took only a little timing to avoid any fighting. Keeping a male and female(s) together year-round helps initiating breeding.

Keeping two adult male Spilotes pullatus together causes territorial infighting. I had two males for some time and kept them together. In the first week, the “dominant” male tried to prevent the other male from climbing to the upper branches, It would follow the other male, crawling over it and sometimes biting it into the last third of the body, preferable to the tail region. This behavior stopped after two weeks, after that the males didn’t show any aggression to each other. However, I would not do this again. I was lucky that my males pretty much ignored each other, but it could have resulted in constant infighting and stress for both of them. It might be helpful to introduce a second male during breeding season to initiate courtship and mating.

When the bioactive enclosure started to work and the clean up crew of isopods and springtails grew in numbers I started to think that this environment would be ideal for dart frogs. I started to investigate if there was any information about co-habitating colubrids and dart frogs and found – nothing, which wasn’t really surprising. After more than a year of planning and thinking I decided to give it a try and bought a trio of Dendrobates tinctorius, a species from the same location as my Spilotes pullatus. When I added the first frog I spent several hours watching it and the reaction of the snakes very closely. The snakes were curious and reacted to the movement of the frog, but never attempted to hunt it, even when it was in easy striking distance (or on top of the snake). 

When the first dart frog had “survived” his first week I added the other two as well. They use the whole enclosure, sometimes even hiding under / between /on top of a resting or basking snake. They provide an additional stimulus for the snakes, because they react to the movements of the frogs, watching them but obviously “knew” that they should not eat something colored like this. Another positive effect I had not expected was the frogs hunting small prey directly on top of the snakes. I saw several hunting jumps for small prey I couldn’t see, but the frog got something and ate it. I provide some Drosophila as additional food for the frogs.

All in all I am completely satisfied how the enclosure worked out. The Spilotes are active during the day and are always eager to eat, but not shy any longer. The plants are doing well, the cleanup crew needs probably a little more time to reproduce enough isopods for that much ground and things to clean. The decision to go with a “regional” plant theme is working great and lends the setup another level of authenticity. The latest addition of three poison dart frogs added another level of enrichment for both snakes and frogs and has now worked for nearly a year without any problems.

By Roman Astheimer

Literature:

Otavio A. V. Marques, Diego F. Muniz-Da-Silva, Fausto E. Barbo, Silvia R. Travaglia Cardoso, Danusa C. Maia, and Selma M. Almeida-Santos: Ecology of the Colubrid Snake Spilotes pullatus from the Atlantic Forest of Southeastern Brazil, Herpetologica, 70(4):407-416. 2014