Indoor Substrates for Star Tortoises
And other small, dry area species
Weather permitting, outdoors is always best. :O)
The choice of substrate is important because your tortoise spends most of his time on it when indoors. If it's too wet, he can develop shell rot, respiratory infections, and other health problems. If it's too dry, he can become dehydrated. And if you have asthma or allergies, it must be something that doesn't make you sick!
What works well for one tortoise keeper, may not work in another person's setting. You'll need to adjust your care and substrate choice based on your tortoise species, type of indoor setup, room humidity and temperature level, and your local area's temperature and humidity. There is no "best" substrate that works for everyone. :O)
If you keep tortoises inside the house in your living areas during the winter and you have asthma and/or allergies, choosing the "right" substrate becomes even more difficult.
Soil, sand, coconut coir
Currently, one of the most often recommended indoor tortoise enclosure substrates is plain garden soil, top soil, or potting soil with no fertilizer, perlite, or other additives.
A common formula is to mix the soil with some play sand. Start with a 50/50 mix and then adjust the ratio as needed. You can use more sand for tortoises from very arid habitats, but tortoises from humid habitats may prefer more soil.
Many tortoise keepers also mix plain soil or play sand with coconut coir as a 50/50 or 30/70 blend.
Caution! Tortoises can develop irritated eyes if the sand is too dry or the sand content in the substrate mix is too high. If that happens, try switching to plain soil.
Soil needs to be watered regularly, otherwise it gets dry and dusty under the hot heat lamps. However, if the soil is too wet, it turns into messy mud. You put a layer of bark mulch or coconut chips on top of the soil to help prevent this.
Just like any other indoor bedding, a soil-based substrate should be changed to a fresh one frequently to avoid it becoming a breeding ground for undesirable "bugs." Always keep the enclosure as clean as possible. Any soiled substrate will encourage the growth of pathogens (microscopic organisms that can cause disease).
Substrate-free eating area
With all loose substrates, especially with sand, it's best to provide a substrate-free eating area to avoid accidental ingestion of substrate during feeding. Eating large amounts of any substrate can lead to an intestinal impaction (blockage) which can be fatal.
You can serve food on paper or place it on a large, shallow plate, dish, or tile. Also, double-plating, i.e., placing a small feeding dish on top of a larger plate, helps keep substrate away from food (pic). See also the bowls & dishes page.
Commonly used substrates include (clockwise from left) coconut husk chips, cypress mulch, fir bark, and sphagnum moss. Sensitive people can have allergic reactions to all of these. For more detailed info on substrates, see the substrates & allergics page.
Thomas H. Boyer, DVM and Donal M. Boyer, a zoo reptile curator, discuss the captive care of tortoises in the 2006 book Reptile Medicine and Surgery by Mader, MS, DVM, DABVP. They mention newspaper, crushed oyster shell, bark nuggets, peat moss, cypress mulch, and top soil as commonly used substrates. They also list carpets, corrugated cardboard, and fine hay as acceptable alternatives. Their advice is to avoid sand, gravel, clay cat litter, crushed corn cob, and walnut shells.
Philippe de Vosjoli, a pioneering herpetoculturist, recommends newspaper as an all-around indoor substrate, fir or cypress mulch for humid loving species, and potting soil for forest species (Popular Tortoises, 2003).
Lance Jepson, MA, VetMB, CBiol, MIBiol, MRCVS recommends a basic indoor setup with newspaper as a substrate. Newspaper is very easy to change when soiled. He feels that naturalistic substrates are too difficult to keep clean because they absorb tortoise urine and retain feces (Mediterranean Tortoises, 2006).
Ian Recchio, a curator of reptiles and amphibians at the Los Angeles Zoo, recommends newspaper, terrarium carpet, wood bark chips other than redwood or cedar, and organic garden soil with no fertilizer. His advice is to avoid sand, coarse bark, and gravel (DIY, 2001, see the Housing section of the Links page).
Today, many tortoise keepers have moved onto more humid indoor setups, even for dry area species. Higher humidity is especially important for hatchlings and youngsters. Hot and dry enclosures expose tortoises to various degrees of chronic dehydration. Warm, damp substrate areas and/or warm, humid hides help prevent fluid loss.
No rabbit pellets
Rabbit pellets and alfalfa pellets used to be popular indoor substrates for tortoises, but they are not recommended anymore because they are very drying, mold quickly, can cause infections, and may induce walking problems.
Similarly, paper has fallen out of favor as an indoor tortoise substrate due to it being slick, drying, and non-diggable. It's best suited for short term, temporary use. For example, in quarantine tubs or for brief, overnight stays indoors when no heating is required. Paper can also be used as a feeding "plate" to keep food substrate free.
Cypress mulch is popular among tortoise keepers because it can retain moisture well. It kind of looks like a pile of splinters. Pieces are sharp. If kept wet, it can start smelling moldy. I am allergic to cypress mulch. It aggravates my allergies whether it's dry or wet.
Substrates for Stars
Star tortoise keepers use various substrates in their indoor enclosures, including finely ground coconut coir fiber (esp. in substrate mixes and humid hides), coconut bark aka husk chips, plain soil without additives, soil/sand mix, sphagnum moss (esp. in substrate mixes and humid hides), soil/coconut coir mix, soil/sand/bark mix, hay, reptile carpet (e.g. handicapped tortoises), paper (short term only), paper towels (esp. for new hatchlings), aspen chips or shreds, repti bark (typically fir), orchid bark, and cypress mulch.
Note: Orchid bark is typically composed of fir or a fir/spruce mix. Choose the plain fir orchid bark.
If you use a dry substrate on Star tortoises, do compensate for it by giving your tortoise frequent soaks (baths). Also provide a warm, humid hidebox and a large, shallow water dish for your Star tortoise. Frequent warm mistings of the enclosure and the tortoise help, too.
Coarsely ground bark with large pieces can create an unstable, difficult to walk on surface in the enclosure. Finely ground bark chips pack tighter making it easier for the tortoises to walk on it, but small pieces are also easier to eat and swallow.
Smooth paper has a rather slippery surface. For subadult and adult tortoises, paper is ok for short-term temporary use, but it's not recommended for small, developing youngsters. Paper towels are a better choice for hatchlings. Paper towels give more grip to feet and nails, and they can be dampened to increase humidity.
Any smooth and slippery surface can cause babies' back legs to slip out when they are moving about in the enclosure. This can lead to permanent gait problems, for example splayed legs. A tortoise with splayed back legs cannot stand tall on them. Rather, the legs are more or less spread out when standing and walking.
All loose substrate materials can cause potentially fatal intestinal impactions if accidentally ingested with food. Some tortoises even eat substrates on purpose! Also, sharp wood particles can pierce the alimentary canal if swallowed. Veterinarians have performed many surgeries on severely impacted tortoises and other reptiles who have consumed wood chips, bark chips, coconut coir, or sand.
Serve food on large reptile dishes, flat stones, trays, plates, or on paper. Do not place food directly on any loose substrate.
Substrates & allergies
Most wood chips, mulches, and soil mixes give out odors that irritate my allergies. Of the loose substrates, dry coconut bark chips seem to smell the least. Unfortunately, when wet, it can have a musty smell. Coconut bark can also be quite "dusty" right out of the bag. Rinsing the chips before use helps remove most of the fine, powdery shell particles.
Read more detailed info about substrates on the substrates & allergics page.
Burmese Star tortoise on coconut bark aka husk chips
Digging & burrowing
Outdoors, Star tortoises are not big diggers, but they can scrape the surface of the dirt when they settle under plants. They do not dig burrows or tunnels like tortoises of some other species.
Captain Thomas Hutton wrote some of the earliest observations of Indian Star tortoises' habits in their native land in 1830's. As described in the 1864 book Reptiles of British India by Günther, Hutton comments how Indian Stars "remain in concealment beneath scrubs or tufts of grass during the heat of the day." During cold weather, they also protect themselves by "thrusting their shells into some thick tuft of grass and bushes."
The above description from the 1830's India fits my Star tortoises perfectly. My Sri Lankan and Burmese Stars also like to hide and sleep under plants, or in their hide boxes, instead of digging into dirt or substrate. They love hiding under clumps of long, thick grass! :O)
My Sri Lankan and Burmese Star tortoises love hiding under tufts of grass. This Burmese Star is sunning herself while staying partially hidden.
Indoors, Star tortoises can burrow into a loose and soft substrate, especially if they have no other acceptable hiding places, or they are tiny babies. Babies hide a lot. I provide my baby Stars multiple hiding places. These include humid hides, dry hides, and various artificial plants. Due to my allergies, I cannot grow any live plants indoors.
If you are allergic to soil mixes and other diggable substrates in large quantities, you can put a "digging box" into the enclosure and see if your tortoise likes it. Just use a low-sided container and fill it with a natural substrate. You can also cover 1/3 to 1/2 of the tub floor space with the loose substrate, or just pile it in a corner.
For more detailed info on substrates, see the substrates & allergics page.
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