Is plant toxicity really an issue?

[Kristina]

You know, I don't worry about it much. I'm not going to go out and plant something that I know is horrdily toxic like deadly nightshade in my enclosures, but at the same time, I'll plant just about anything that catches my eye and fits in with the theme of the enclosure. Not every single plant that tortoises come across in the wild are non-toxic. They HAVE to have some instinctive knowledge about what is edible and what is not. If they didn't, there wouldn't be many tortoises, lol.

A lot of the plants that are in my "forest" enclosures (Box turtles, Redfoots, Manouria, Hingebacks) are plants that I collect out of the woods. (Always be sure not to take every plant of any species from one given spot, leave some to reproduce for the next year, and only collect out of areas that you know are not sprayed or otherwise treated with chemicals.) Very few of them are on the lists of toxic/non-toxic plants. However, they create the environment that I want for my tortoises, and are very easy for my to care for. They thrive well without excessive work.

 

[Tom]

Addressing the original post:

Haha. You've never had a sulcata have you GTT? (said with a devilish smirk...)

Sure in the wild with 100s of square miles and all sorts of seasonal variations and 1000s (or more) of plant species to choose from, they make good decisions. Put that same animal in a bare dirt pen feed him light for "slow growth", which is often advocated, and after a few months of feeling like they are starving, and they will eat ANYTHING that falls or blows into their pen. I see this sort of thing with all captive animals, not just tortoises. So do vets. Ask a vet what sort of things they've pulled out of animals and tortoises. I once had to stop one of my sulcatas from eating oleander. Had to pull it out of his mouth.

The bottom line is that in a large, well planted enclosure, with abundant food, they will usually make good decisions as we have all witnessed. But I think some of us at least, have also witnessed them eating things they shouldn't. Sometimes a captive situation will do funny things to an animals mind and cause them to do things that they normally would not. I once watched an ostrich panic and pull his own head off. I've seen horses freak out and run straight into a wall and break their own neck. I've seen all sorts of animals eat all sorts of things they shouldn't. For me, "usually" is not good enough. If they don't have access to a toxic plant, they can NEVER eat it, no mater what.

 

[Terry Allan Hall]

A lot of people are interested in which plants may be toxic to tortoises. However, it seems that my tortoises only like to eat plants that are safe, and never try to eat more exotic fair. In captivity, some pet tortoises might not have a good diet, but that has more to do with safe foods in the wrong proportions, rather than plant toxicity. If pet tortoises eat too much fruit, for example, it's only because they encounter more than they would in the wild. And if they can't detect pesticides and herbicides, it's only because they have no evolutionary history with this chemicals. Moreover, tortoises can even detoxify some plants that would be dangerous for mammalian herbivores, such as sheep and horses, to consume. Thus, except for artificial chemicals and unnatural abundances of food, it seems that tortoises have excellent nutritional wisdom, and instinctively know what is good to eat, and what is not.

Given the above understanding of tortoise feeding behavior, I am a bit puzzled as to why people are concerned about tortoises' eating toxic plants. If it's safe to eat, they'll eat it. If not, not. Right? Maybe we should be more concerned with the right amounts of good plants to give them, rather than toxic plants. Has anyone out there ever actually had a tortoise or turtle become ill or die as a result of its eating a toxic plant?

For me there is no debate here. I agree with GeoTerra, JoesMum & terryo. I will go as so far to say that when I pick weeds for my tortoises which is nearly two full 33 gallon size trash bags about every 2-3 days, I pay little attention to what underlying weeds I am ripping out of the ground along with the known "safe" ones. I steer away from the very obvious known toxic weeds when I see them but there is no doubt that I pull up several of them when picking taller safe weeds. I've been doing that way for over 25 years and have yet to have a problem that could be attributed to them eating toxic plants. Some of my enclosures have Boxwood shrubs planted in them, a supposed known toxic plant. I planted them because they grown thick and low and provide good shade. My tortoises totally ignore them despite the plants having very green, very lush leaves within their reach.
I'm a firm believer that they know more about what they can eat than we do.

Agreed...I've never seen any of my tortoises eat a plant that was toxic to them, although I know my daughter's Box Turtles love to eat mushrooms that would kill me (an amusing, if perhaps not absolutely PC anecdote: In the early days of White/Cherokee relations - around the early 1700s - if my ancestors liked you, they'd tell you why they do not eat box turtles, but if they didn't, they'd still leave a string of beads to help you on your way to The Land Afterwards...)

 

[GeoTerraTestudo]

1. Nutritional wisdom. This refers to an animal's instinctive knowledge of what is good and bad to eat- in captivity. Tortoises are considered to have poor nutritional wisdom insofar as they will often eat whatever garbage is available no matter how poor it is for them nutritionally (if they had good nutritional wisdom, they would not get MBDs so easily). Of course, since they can eat such a wide variety of foods and mostly live in places with such a poor selection of available options, they really don't need a lot of nutritional wisdom.

Great comments, Mark. However, when it comes to nutritional wisdom, I rank turtles pretty highly. These animals have no evolutionary experience with plastic bottle caps or other kinds of garbage, so it should come as no surprise that they might try to eat them. However, with respect to things they have evolved to recognize, like plants, fruits, and invertebrates, they seem to be very good at knowing what's worth trying and what isn't.

As for MBD, I think a lot of reptiles get it in captivity, simply because the conditions are so different from what they really need. Whether it's a lizard, a turtle, or a crocodilian, reptiles need plenty of calcium and vitamin D3 in their diet and from basking. It's not the reptile's fault if his keeper doesn't know what to feed him, or what kind of environment to provide. Some turtles get MBD because their keepers keep them in a 10-gallon tank and only feed them iceberg lettuce, and there's really not much the turtle can do about that. Iceberg lettuce is not toxic, so they eat it. Obviously, they need a much more diverse and nutritious diet than that, as well as a better environment, including UVB and hopefully time outdoors. But the MBD doesn't come from poor nutritional wisdom, it comes from poor husbandry.

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Haha. You've never had a sulcata have you GTT? (said with a devilish smirk...)

The bottom line is that in a large, well planted enclosure, with abundant food, they will usually make good decisions as we have all witnessed. But I think some of us at least, have also witnessed them eating things they shouldn't.

LOL ... point taken. Sounds like, if a tortoise is hungry enough, and is able to get into all sorts of strange things, who knows what it might end up eating?

 

[Tom]

LOL ... point taken. Sounds like, if a tortoise is hungry enough, and is able to get into all sorts of strange things, who knows what it might end up eating?

Right. I consider most of the regular posters here a pretty elite group. Very experienced and knowledgeable. Even though we may disagree and use different methods, I think we all maintain excellent enclosure, feed a healthy diet, and do the right things necessary to maintain healthy tortoises. As an animals professional for the last 26 years, I have also seen the "other" side. I have seen many sad situations involving complete ignorance and or apathy, and lots of dead or dying tortoises. When we (the regular posters) talk on this forum, I think in most cases we can assume the best, and there is a lot that is just understood among us. I don't think your average tortoise keeper out there keeps their enclosures as well as TerryO or Terry AH. I don't think Dennis or Mark or Kristina or JD or ANY of our regulars could be considered anywhere even remotely near "average". It does not surprise me that EXTREMELY well cared for and well fed tortoise are not eating the wrong things. I'm just saying, that this is a different discussion if we are talking about the "average" tortoise keeper out in the world. Comparing one of of Kristina's (just for example) awesome super healthy tortoises to one of my neighbors tortoises kept on bare dirt in a plain, undecorated in any way, rectangular pen, is two TOTALLY different things. I would expect to see different things with each animal.

 

[CLMoss]

I would be very careful...

 

[Jacqui]

I am mixed on this point. I think the "normal" tortoise, will know which plants not to eat if they are native to his natural environment. I think some however will eat things not native to them or eat them because they are hungry or even bored, those behaviors can lead them into problems.

When I plant anything into one of my enclosures I look at what animal will be housed there. I know for instance my hingebacks will rarely touch anything in their enclosures, so any plant is pretty safe for them. Now if we are talking the Russians, no plant is safe with them as they eat everything. This means I won't be planting something like tomatoes in their enclosures. If your talking a very small youngster, with their small body mass, even a little bit of something can have big consequences for them, so I am more careful with them. However with the larger two sulcata with their bigger body mass, I really don't worry much about them. So for me how "paranoid" I am depends on what species, it's eating habits, and it's body mass. I also don't go with what the "lists" say are toxic, I do more asking around and go by the experience of others, too.

 

[LeaderLeprechaun]

Tbh Im glad this thread popped up. I know that personally Im borderline with "being on the safe side" and letting the torts pick for themselves. Being an Environmental Biology major with studies in animal behavior Ive noticed that animals overall know what they should and shouldnt eat, so I do agree with this point of view. However, I do also agree that those animals which are captive bred may not entirely understand what is good or bad due to not being exposed to it before. In my personal opinion, finding that my tort was not captive bred I tred on both sides. I have looked at the tortoisetable sites as well as many others to decides what can and cannot be fed or in the terrarium. This is a good topic though and Im personally glad it was brought up.