Fiber, what exactly is it? Fiber consists of pieces of food that will not be digested, but aid in digestion, by providing a sufficiently firm substrate for the intestinal walls to act on – moving a bolus of food along the digestive track. Fiber is also a place that microbes can reside on, to the point that the ‘particle’ size of the fiber will influence what the variety and populations of different digestion aiding microbes are able persist in the gut and the balance of many types of microbes.
Fiber is not always microscopic, it can and should be large bits of plants or their seeds that are readily seen in the fecal pellet. Those are the indigestible veins of blades of grass, the network of vascular tissue in tree leaves, the petioles and soft bark of trees and shrubs. For forest species as well as grassland grass and broadleaf eaters, this also includes seeds.
As a side note, tortoises are significant seed dispersing animals, that is – the seeds they eat, and later expel, grow. The frequency is high enough that tortoises are consider important seed dispersing animals in the ecology of the habitats they live in. It is more than just an occasional or accidental ingestion. At least one in-situ study of enclosed south American tortoises, it was noted by the authors that when not given ‘seedy’ plant matter to eat, the incident of rock eating increased. Their interpretation of this behavior was the value of seeds in the diet as a ‘fiber’.
Seed size and type are critical to consider. The soft seeds in young summer squashes seem to be universally acceptable to all but the youngest neonate tortoises. Seeds with a squishy soft tissue on them, like papaya are great, as are those seeds in okra. Winter squashes like pumpkin, and butter nut are also good seedy plant choices (fresh, not dried) as the pulpy stuff keeps them slick. Mellon seeds and cucumber seed also work well. Avoid things we commonly think of as pits, they have uneven surfaces and tend to be too big, like from a plum, apricot, or peach.
The last consideration is size of seed to size of tortoise. I use a rule of thumb, at least ten seeds should be able to fit in the mouth in an ‘average bite’ to not be too big for the specific tortoise.
Then there are all those more traditional ideas of fiber for tortoises, grass, grass, and more grass. Given a choice and free range most tortoises will choose broadleaf leafy plants over grasses. These can be from low shrubs, fallen tree and shrub leaves, and weedy plants on the ground. Grass is what is left by default and a good diet fiber source.
Different grasses taste different fresh and dry. Different ages when harvested increase this range of palatability. I often read about people becoming frustration with getting a tortoise to eat dry grass, I’ll offer more about that further along in this blog post. No matter, try different grasses in different forms. If a dry form, fresher is better. I learned from one organic hays producer that the often sought Timothy hay is one of the least palatable grasses in the field, that cows and horses will eat it as a last resort.
Also consider pellets, which often come in blends of more than one type of grass. There are a few pellet sizes as well, they are not all the same diameter, there are cubes too. The larger the pellet or cubes the bigger the largest pieces will be.
Orchard, broom, fescue, oat, rye, and timothy are types of grasses available in blends and as stand alone varieties in pelleted/cube form. Most can be found mail order if not locally. Finding organic produced hays is difficult as the demand is very high.
Some hoarse food stores will let you have the hay/grasses that falls off bales, for free, if you sweep/rake it up.
There are a few non-grass plants they are bailed, alfalfa and clover. Both of these are good sources of fiber as well, and used sparingly, the slightly higher protein content should not be an issue. Alfalfa actually has vitamin D2 and more surprisingly vitamin D3 in it.
Getting that tortoise to eat any kind of dry plant matter, if grass or broadleaf can be difficult. I find tortoises get to be selective herbivores – reluctant to eat novel things, but that makes sense. When a baby tortoise first starts finding things to eat, they would seem to prefer small live leaves that are young, with high water content, and easy to bite. That makes sense, as water is so important, and they are small so their reach is very limited and their bite strength is poor.
How do they become dry grass/leaf eaters in the wild? Over time they accidentally eat dry bits of plants mingled with the fresh leaves, this becomes a more frequent ‘accident’ until the ‘dry season’ and there is no more fresh. Grasses usually persist longer in the dry season, as well, they are more fiber-y with long parallel veins. That’s where the grass eating comes into the life of a tortoise. Offering dry stem-y bits of old grasses is a huge leap in eating behavior for a tortoise. It has to be gradual, very gradual, especially for baby tortoises more or less learning how to eat in their first year of life.
Start with whatever they are getting fresh, but in a dry form, even if grocery store greens or backyard green, The proportion should be very small, about 5% or less. If rejected the first time, persist. If they at first pick and choose carefully to avoid the bits of dry, reduce the total amount offered. It’s a process of funneling their behavior.
Over many meals, they will be less resistant or maybe show a preference for the dry bits of food. Dry flower petals, rose, pansy, dandelion, etc. can help bridge the gap from fresh to dry. If you use a large volume of backyard greens, dry some, or pick parts that have dried on their own, and mix it up. If using large/whole leaves brings too much pickiness, then try chopping with scissors or a knife and tumbling the dried with fresh greens so the effort to pick and choose is greater.
There are many routes to drying backyard greens. It can be done most simply by running a fan over the greens while those green sit on paper or cloth towels, sun drying is not suggested, it reduces some of the nutrient content. There are many venues to buy dehydrators on-line, and DIY build plans fro free.
All this fuss about fiber, how do you know if it’s working? It’s all in that little gift left behind in the water dish or the substrate. If the feces are watery, that in itself is not bad. If you use grocery greens they have a high water content and so will the poop, wait overnight, if the same shape is still there, but the stool is slightly smaller, then excess water dried off. If the feces collapses, or has no form or shape the fiber content should be increased.
Often with larger individuals, that graze on grassy areas, you will get what looks like a ball of chopped grass, at first wet, then with time they dry into what looks like a grass pellet. That’s excellent.
If the stool come out looking like black clay, with no moisture content, perhaps more soaks or higher water content food should be offered.
It is not within the scope of this blog to diagnose or offer treatment suggestions for health issues that may be caused by an imbalance of gut microbes. I will get a fecal analysis done whenever I have some other reason to bring a tortoise to the vet. The initial reaction from the vet or tech looking at the fecal is often something like “wow, there are alot of ciliated protozoans in the fecal, we’ll get lab results back ASAP.” The lab result will suggest the amount and type are ‘normal’ for the tortoise. So please don’t panic if an enthusiastic vet tech makes a similar report. Keep fiber content and variety (particle size) high and wide and that will help a great deal in keeping that tortoise guy healthy.