Tortoises and their dietary preferences can be very strange, sometimes tortoises will eat everything that is in front of them (even if they shouldn’t) and other times they will become some of the pickiest eaters in the world. But how do they feel about watermelon?
Tortoises can eat watermelon, but not too much. Like most fruits, watermelon contain phosphorus, which can be harmful to tortoises in high quantities.
Watermelon are good and bad at the same time. They are good due to the high quantities of vitamins they contain, like B6 and C, but at the same time they are bad due to the high amount of phosphorus.
If you can manage the calcium:phosphorus ratio, you can safely give your tortoise watermelon. So let’s start our discussion with that, after which we will see how much and how often you should give your tortoise watermelon.
The Calcium Phosphorus Ratio of a Watermelon
Almost all fruits contain calcium and phosphorus. And as a result, most of them have a calcium to phosphorus ratio. So let’s take a look at what calcium does for tortoises, what phosphorus does for them and what is a good calcium to phosphorus ratio.
Calcium is essential for every animal in this world that has bones. And since the shell of a tortoise is made out of bones, calcium is even more important for tortoises than for any other animal. Fruits are one of the main sources of calcium that a tortoise has, so making sure that you feed them vegetables with high amounts of calcium is important.
For humans, phosphorus is a very important mineral that helps filter waste, repairing tissue and cells, etc. But for tortoises, phosphorus is not that great. Phosphorus is what gives tortoise shells a little flexibility, which is great because this little extra flexibility makes them more resistant to bites and other types of impact. But too much phosphorus can also make the shell a lot softer, and as a result much weaker when it comes to defending the tortoise from predators.
In short, we can say that calcium is great for tortoises and phosphorus is not so great for tortoises in high quantities.
Most fruits have a calcium to phosphorus ratio, this ratio can be 1:1, 2:3, 5:2, 1:2, etc.
A 1:1 ratio means that the amount of calcium is equal, or almost equal, to the amount of phosphorus. So a vegetable with this ratio is not that great for tortoises, but it’s not harmful either. But if possible, such a vegetable should be avoided.
A 1:2 calcium to phosphorus ratio is really bad, there are not many vegetables with this ratio, so don’t worry too much about them. Just remember that if a vegetable has more potassium than calcium, you should keep it away from your tortoise.
A 2:1 ratio is great, and this is what you should be aiming for. If the ratio goes higher, it’s ok, but ideally this is the ratio that you are looking for.
Watermelon has a 0.9:1 ratio, which is not ideal. But at the same time, it’s manageable. And of course depending on the way the watermelon has been grown the ratio will look a little different from, but overall it should still be in the same area.
Here is a short list with some fruits that have a high phosphorus content and should be avoided in large quantities:
Here is a list of some of the most common vegetables and their Calcium to Phosphorus ratio:
- Grapes – 1.4:1
- Apples – 1.1:1
- Pineapple – 1:1
- Mango – 1:1
- Pears – 0.8:1
- Strawberries – 0.8:1
- Guavas – 0.8:1
- Cherries – 0.8:1
- Apricots – 0.7:1
- Blueberries – 0.6:1
- Peaches – 0.5:1
- Bananas – 0.3:1
- Plums – 0.3:1
How Much and How Often You Should Give Your Tortoise Watermelon
While watermelons don’t have the best calcium phosphorus ratio, they still have a lot of beneficial vitamins, so they shouldn’t be excluded from the diet of your tortoise entirely. They should be treated more as a snack or reward than a staple in their diet.
I feed my adult tortoise about a slice of watermelon once every two weeks, during the summer. And I wouldn’t recommend you to give your tortoise any more than this.
If your tortoises have a balanced diet, a couple of watermelon slices once every few weeks won’t do them any harm, and it will allow them to benefit from all the good parts of the watermelon.
If you have a younger tortoise, you should reduce the amount to one per week.
Now let’s see what are the benefits of a watermelonfor a tortoise.
The Benefits of Watermelon for Tortoises
Watermelons are full of vitamins that make them worth feeding them to your tortoise, despite their not so great calcium phosphorus ratio, but the most abundant and important are Vitamin B6 and vitamin C.
Vitamin B6 plays a very major role in energy conversion. To put it simply, vitamin B6 helps tortoises remain energetic throughout the day, without it, they will feel tired constantly. Vitamin B6 can be mostly found in berries.
Vitamin C, as you know, plays a very important role in the maintenance and development of the bones. And since almost the entire body of the tortoise is covered with a shell, which is made out of bones, vitamin C is essential for them. Lucky for tortoises, vitamin C can be found in most fruits, so they don’t usually have deficiencies.
What to Do If Your Tortoise Doesn’t Eat Watermelon
The first thing that you have to do is to determine the cause. And there are two possibilities.
One possibility is that your tortoise simply doesn’t like watermelon, one of my tortoises is exactly the same.
In this case, you could reduce the amount of food that you usually give it and replace it with watermelon. But I would advise you against this. While watermelon is good for them, they can still get the same benefits from other fruits.
If your tortoise doesn’t like watermelon, you shouldn’t force it to eat them. As it’s just a matter of taste. Every tortoise is different, some will like watermelons, some won’t.
But if your tortoise refuses to eat any kind of fruit, then you have a problem, as fruits can’t be completely removed from their diet. If this is your problem, you should start replacing some of the food that you usually give your tortoise with fruits. And it shouldn’t take more than two or three weeks until your tortoise will start eating fruits.
The second possibility is that your tortoise is too young. It’s not uncommon for baby and juvenile tortoises to not eat certain fruits. When tortoises are at those life stages, they are growing a lot faster than adult tortoises, and to grow this fast they need a lot of protein that they get from greens like: spinach, watercress and cabbage. Eating watermelon, while it will keep them from starving, it won’t do them too much good at this point.
If your tortoise is young, then it’s perfectly normal that it won’t eat watermelon. Just wait until it reaches maturity, then you can try again to feed it watermelon.
If you are not sure how old your tortoise is, then read this article: How Long do Tortoises Live?, there you will find a few methods that will help you approximate the age of your tortoise.
Final Thoughts
Tortoises will normally eat watermelon, as well as other fruits. Just be careful not to give your tortoise too much, since they can be bad if consumed in excess.
I hope this article answers all your questions, but in case you have any questions left, you can always leave them in the comment section and I will answer them as soon as possible.
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