# "Safe Plants" - is the poison in the... square footage?



## SarahChelonoidis (Jul 11, 2015)

In thinking about plantings for my work-in-progress footed habitat, I am wondering how much of their native habitats can we realistically - safely - create. 

The Vinkes and Vetters provide a great list of native plant species that footed tortoise eat fruit/flowers from in their 'diet' chapter in 'South American Tortoises', but I'm not sure if there are safety concerns with growing some of these species in confined spaces. Many of the trees and shrubs that produce the fruit that make up the native footed diet also produce a variety of interesting toxins found in the leaves or seeds of those same plants (whether these compounds are toxic to tortoises is another question that I don't think an answer exists for yet). While these tortoises are well known for swallowing and transporting seeds intact, I don't know if, in the confined space of a captive habitat, the same rules would apply.

Annona squamosa (sugar apples), for example, (which are eaten by footed tortoises in the wild and then later 'planted') would be easy to grow and get decent fruit yield from in an indoor habitat, but their seeds - if broken- are known to be fatally toxic to many insects and mammals. Like for pretty much everything, lethal dose evaluations aren't done on tortoises, so it might not be an issue at all if they were to decide to crunch the occasional seed... or maybe it would be? Annona spp., like many other plants the Vinkes and Vetters reference (ex. Trattinickia rhoifolia, Spondias mombin, Duguetia spp., Mauritia flexuosa_, _etc.) are known for medicinal properties, which means in some concentration they are likely to be toxic to mammals, but that doesn't mean much of anything in terms of their potential impact on a tortoise. Philodendron spp. provide fruit for wild footed tortoises but their leaves and stems are known to be fatally toxic to some mammals if ingested - does this really tell us anything useful for creating captive tortoise habitats?

If in their native range they encounter say, 10,000 different plant species, they may eat a mildly poisonous leaf or seed here-or-there, but with all their choices available, you likely wouldn't have to worry about the build-up of any one particular toxin in their system. In a captive habitat, where they encounter say (overly optimistic) 50 different species of plant, they are likely going to be nibbling the same things more frequently. Where a fallen leaf in the wild might not catch their attention, in a greenhouse enclosure, boredom might make that leaf more appealing.

Is it worth the 'risk' to include native food sources with potentially toxic parts in the tort habitat? Are there safety concerns in small, low diversity habitats that don't exist in more natural ecosystems?


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## Alaskamike (Jul 24, 2015)

Very interesting observation and question. I am convinced that optimum health comes from variety. Too much of a good thing is still too much. I watch my torts graze sometimes. In their enclosures there are amny weeds, grasses plants. some I panted, some spring up from seeds blowing in. The torts take a few bites of almost everything, with a few weeds they just never seem to touch. 

My suspicion is, they do on occasion take bites out of toxic plants. A small amount it probably mitigated by the variety and their digestive systems. But in nature they can wander many miles and find a great variety of stuff to eat. In an enclosed yard they are limited. We do not need, nor do our environments need the tort for seed proliferation, but i the wild this is a function they serve. 

I would not have anything that is toxic growing in their yard/surrounds if possible. What I wold do is provide leaves of plants that are good for them, while keeping the parts of the plant (like the fruit, or seeds) away from them. I kind do this with grpe vines, they eat the leaves but not the grapes.

Good question.


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## Tom (Jul 24, 2015)

Both of you raise valid points and questions. I certainly don't have the answers.

I have observed many tortoises deaths from tortoises eating toxic plants in our artificial captive environments. The notion that tortoises have survived without out help for millions of years without our help and know what they should and shouldn't eat does NOT apply in our captive environments in foreign (foreign to the tortoise species...) places with foreign plants from all over the world.

I have chosen to stick with known safe plant species. Further, I have to select plant species that can survive in my climate.

Trying to replicate a wild habitat covering hundreds or thousands of square miles and containing tens of thousands of plants species, in a backyard in a foreign climate doesn't seem viable to me. Picking 10 or 20 known safe, edible plants and maybe attempting a few plant species that are known to occur and be eaten from the native environment of a given species seems like a much more practical and prudent goal to me.


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