Why Are My Turtles Stacked? 3 Shocking Answers and Solutions

Apr 19, 2021

Why are my turtles stacked

Have you ever seen turtles stacked on each other like they’re about to break into a synchronized performance? It’s quite an exciting sight — and the reasons behind this are even more intriguing. 

Let’s find out! 

Why Do Turtles Stack?

The main reason behind turtles stacked on each other is to receive UV rays from a light/heat source. Captive turtles usually show this behavior when there’s not enough basking area. Other possible causes are to deter predators and exert dominance in the group/bale. 

As it turns out, stacking on each other is a natural, instinctive phenomenon among turtles. And while it may seem amusing to us, there’s more than what meets the eye. 

So let’s dissect the motives behind turtles stacking on each other. 

Top 3 Reasons Turtles Stack On Each Other 

Turtles stacking on each other
Turtles stacking on each other

Turtle Isn’t Receiving Enough UV Light 

As ectothermic creatures, turtles rely on the environment for their body heat. Turtles often resort to piling up on each other and receive their share of UV light, which is crucial to their wellbeing. They show this behavior if the light source is too weak or there’s not enough space for everyone to spread out. 

UVB light is imperative to a turtle’s health since it helps synthesize Vitamin D3, which helps absorb calcium. Inadequate UVB lighting leads to a condition called hypocalcemia (lack of calcium). And in turn, negatively contributes to the turtle’s bone and shell health. 

Turtles Are Trying To Deter Predators 

In the wild, turtles are most vulnerable to attacks when they’re basking. A solitary turtle may seem like easy prey. But in the animal kingdom, when turtles pile up on each other, it gives an impression of a more giant, stronger creature — lessening the chances of an assault. 

For instance, a pond turtle’s archenemies are alligators. For the latter, hunting down a single turtle is a walk in the park.

So, turtles are often known to engage in tricks to form a more imposing figure and ward off hunters. That way, the alligator will have to bite through many layers of shells before laying teeth on the meat.

Another unique way turtles fend themselves by stacking is by evaluating the area from a height. Extra pairs of eyes are always good, right?

The turtles on the top are usually tasked with watching over the water and the nearby vicinity for any signs of danger. 

Turtle Is Showing Dominance In Bale 

Turtles don’t have a well-established social hierarchy like some animals do. However, several turtle enthusiasts have reported that dominant turtles are almost always on top. It could be possible that the ‘powerful’ turtles are exerting dominance among juveniles and weaker ones. 

But since turtles aren’t social beings and stacking isn’t exactly a social activity, I’m not sure if this reason is 100% plausible. 

Anyway, if you notice some turtles are on top of the pile most of the time, this is an interesting possibility to explore. 

How Does Turtle Stacking Work?

When turtles stack on each other, they can produce more heat than they would have produced alone. While the turtle on top is closer to the heat/light source and receives the first advantage, the ones at the bottom will receive the collective heat produced by all turtles above them.

Here’s an interesting video of turtles stacking on each other:

Although the stack’s height may not seem too impressive, it’s just enough and very much effective in producing and transmitting heat for turtles. 

Stacking plays a critical role, especially in the case of pond species like red-eared sliders and painted turtles. These semi-aquatic turtles need to quickly dry and warm themselves to a specific temperature before diving back to water and finding meals. 

Thus, you can often semi-aquatic/pond turtles stacked on each other in their natural habitat. 

Does Stacking Hurt Turtles At The Bottom?

When preparing to pile on each other, we seldom see turtles scrambling for the first position. So, there’s no concrete evidence if the bottom turtles are at a disadvantage. However, there are concerns for pressure on the shell, less exposure to warmth, and bullying. 

While the caveats on bullying and lesser warmth exposure are up for debate, you don’t have to worry about the shell weakening or getting fractured. 

This study reports that to break the shell for a turtle of a given weight, you’ll need 40 times the bite force of an average predator of the same weight. 

And in most cases, the stacking positions aren’t permanent. They often interchange between sessions. 

Thus, there shouldn’t be any qualms about 3 to 4 turtles stacking on each other occasionally. Don’t worry! 

Can Turtle Stacking Cause Bullying and Fighting? 

An appealing avenue to explore — but no, turtles stacked on each other rarely culminate in fighting and bullying. That’s because stacking is an innate communal behavior carried out for survival by receiving heat and fending predators. So while this isn’t exactly a fun group activity, usually there’s no social hierarchy and tension. 

That being said, we cannot overlook the experiences shared by some turtle owners in forums. 

Some accounts report that almost always specific turtles are on top and rest at the bottom. Thus, we cannot rule out behavioral issues here. The underpinning reasons could range from mating and starving to territorial aggression. 

In these cases, it’s essential to inspect for signs of injuries and shell rot in turtles at the bottom tier. 

Why Are My Pet Turtles Stacking? 

Actually, pet turtles stacking on top of each other isn’t an uncommon sight. The main reason behind this is the poor basking arrangement. Make sure that there’s enough basking space and enough light for everyone. Additionally, turtles also stack when scared.

Turtles stacking
Turtles stacking

Your Basking Area Is Too Small 

For turtles, a basking area is as vital as clean water and a spacious tank, if not more. If there’s not enough basking area for everyone, turtles simply have no other options than stacking on each other. And while this may seem harmless at first, you must address this issue. 

For instance, consistent underexposure to warmth will invite various health complications from infections and shell rots to fragile bones and disformations. 

Likewise, this can also trigger negative behavioral issues if your turtles have to constantly compete for the basking area. 

Small and juvenile turtles often bear the brunt of any fight that breaks out in the tank. 

Your Basking Area Isn’t Well-Heated 

Another common reason behind turtles stacked is a poorly lit and heated basking area. It’s necessary to understand the basking needs of your turtle species and fit lights accordingly. For instance, adult Red-Eared Sliders need around 90 – 95°F, while juveniles need a slightly higher temperature of 95 – 100°F. 

The rule of thumb is that the basking area should be slightly over 10°F or 5-6°C warmer than the water. 

For most adult turtles, a suitable basking temperature ranges between 85 – 95°F. 

If you’re interested, here’s our detailed guide with features temperature requirements for most pet turtles. 

Your Turtles Are Scared 

One might think about what reasons do pet turtles possibly have to get scared. But does your tank area receive a lot of footfall? Is there too much noise? Or are your curious kids and furry pets prying out of curiosity? These reasons are more than enough for turtles to feel scared and potentially pile up to defend themselves. 

As you already know, turtles aren’t sociable creatures. They enjoy the best when alone or in the company of their own species. Thus, you can consider moving your tank to a relatively quieter area in the house. 

But most importantly, don’t forget to teach the curious onlookers to respect the turtles’ boundaries. 

Well, now that the main reasons behind pet turtles stacked are clear, let’s have a look at some practical solutions. 

Suggested Readings:

Cloudy Turtle Tank Water? Don’t Make These 4 Mistakes!

How Do Turtles Breathe? Butt-Breathing to Breathing Without Oxygen: A Turtle’s Unique Respiratory Abilities

How To Stop My Pet Turtles From Stacking?

To stop your turtles from stacking upon each other, the most significant bit is to ensure there’s enough basking area and light for all turtles. Since turtles also tend to pile when scared, ensure that their tank is a safe, quiet area away from inquisitive eyes. 

Increase Basking Area 

Quite simple – if the basking area isn’t large enough to accommodate all turtles, increase the size of the basking platform! You can also invest in personal basking platforms, so the turtles don’t compete with each other. 

This one here by Penn-Plax seems like a great option at an affordable price range. You can choose from small, medium, and large sizes based on the number of your turtles and their sizes. 

Penn-Plax Turtle Pier

This beautiful turtle pier rests on 4 pylons attached to the suction cups and floats just above the waterline. You can modify the supports as low as 3 inches for waterless tanks to as high as 12 inches for watered tanks. 

Personally, the most standout feature for me is that it’s built in a way to also allow turtles to hide and rest underneath — satisfying their instinctive behavior. 

Proper Lighting Arrangements 

If the basking lights are simply not potent enough for your turtles, they’ll inevitably pile up on each other to bask and generate heat. To tackle this problem, ensure you have the right lights on the correct settings. 

However, the information on the light’s packaging usually only includes watt information and not temperature. For instance, it’ll say 30 watts or 50 watts – not 95°F.

That’s because a 50-watt bulb can generate both 75°F and 100°F temperatures. The amount of heat generated is also influenced by the distance from the ground. 

This table here gives a rough idea of how much heat bulbs will generate from different distances: 

For 50 Watts

Inches Fahrenheit
4104°F
881°F
1273°F

For 75 Watts 

Inches Fahrenheit
4120°F
891°F
1281°F

For 100 Watts

Inches Fahrenheit
4131°F
8113°F
1290°F

Here’s one of my favorite bulbs for the classic two-bulbs setup by Zoo Med. 

Aquatic Turtle UVB & Heat Lighting Kit

You can choose from 50, 75, and 100 Watt options. In addition, its polished aluminium dome can increase the light and UV output by up to 30%. 

But if you prefer bulbs that give both heat UVB light and heat simultaneously, you can opt for mercury vapor bulbs like this one from Evergreen Pet Supplies

UVA UVB Mercury Vapor Bulb

This product enjoys a lot of 5-star reviews, and I didn’t come across any comments on bulb explosions that are sometimes the case with these kinds of bulbs. 

Reportedly, each bulb goes through a 3-step testing process to ensure safety and proper functioning. 

Take Them On Short Outdoor Trips 

Even if turtles don’t complain or protest much, it’s never fair to keep them within 4 walls all the time. Irrespective of the excellent arrangements you have made for basking and swimming, it’s crucial they receive some natural sunlight and fresh air once in a while. 

Thus, make sure that you occasionally take them for some backyard excursion and let them explore and forage on their own terms. Most probably, they’ll also sit under the sun for some time to absorb much-needed warmth. 

However, you must supervise your turtle so that it doesn’t wander away to danger zones. 

Conclusion On Why Are My Turtles Stacked

Both in wild and captivity, turtles stack on each other for similar but a multitude of reasons. 

So, here’s a quick rundown of all the significant bits on why turtles pile up on each other: 

For starters, the main reason behind this tendency is to receive UV light crucial for their health. If the basking area is too small or the light source is too weak, turtles stack upon each other to get closer to the light source and generate warmth. 

Scared turtles also stack to create the impression of an enormous, stronger creature to dodge predators. In the wild, their natural and common nemeses are alligators. But in captivity, this could be due to big noise and prying kids and pets. 

And lastly, it’s also believed that turtles stack on each other to display dominance. However, there’s no concrete science backing this claim. 

So, if you find your pet turtles stacked often, it’s time to reevaluate their basking arrangements and make necessary upgrades. 

Relevant Readings:

Do Turtles Eat Goldfish? What Happens If They Do?

Can Turtles Get High? Here’s Why You Shouldn’t Get High in Your Turtle’s Presence

How Often Do Turtles Poop? Everything You Need to Know About Turtle’s Poop

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.