Most owners get scared or stressed when their bearded dragon is turning black. The most common questions are ‘why is my bearded dragon turning black?’ or ‘why is my bearded dragon’s beard black?’ and so on. There are many reasons why your bearded dragon might be turning dark. In this post, we will discuss different reasons why a bearded dragon is turning black and how to act in these situations.
Why is my bearded dragon turning black?
Reason number 1: Your bearded dragon is cold and is trying to warm up
The fact is, your bearded dragon might turn black or just darker to increase heat absorption. This can happen if the tank is cold, and your bearded dragon needs more heat.
This also happens after a night, because temperatures drop. But this is not likely to happen in the terrarium – if you have automated lighting and heat.
What are ideal temperatures in a bearded dragon’s tank? Make sure that the temperature in the hot spot under the basking + UVB light is 92-105, even up to 110 degrees Fahrenheit (33-43 Celsius).
Temperature in the cool spot should be around 75-85 degrees Fahrenheit (23.8-29.4 Celsius). During the night, temperature should not drop lower than 65 F (18.3 Celsius). 
Make sure that the fixture or bulb that you have in the tank emits UVB light. Some fixtures (for example for plants or people) are not meant for reptiles, so don’t emit any UVB.
What is more, make sure to replace UVB lights every 6 months. This is because UVB lights stop emitting any UVB with time, and you won’t be able to tell the difference.
One of the best choices for an UVB light source is to get a Reptisun 10.00 (not less than 10.00) HO (high output) UVB fixture like this. Place the fixture 6-8 inches above your dragon (highest point), not less and not more.
What is more, you will need to place a basking light near the UVB source. If you wish to combine UVB source and light source into a one bulb, you can use a mercury vapor bulb that produces UVB, visible light and heat.
Be careful and don’t use it in a tank that is smaller than 40 gallons – the mercury vapor bulb gets very hot.
You can read the full guide to lighting here.
Reason number 2: Your bearded dragon is ready to mate
Believe it or not, your bearded dragon’s beard can turn black during a breeding season. This often happens to male bearded dragons when they are ready to mate.
Male bearded dragons mature faster than females – males can start showing breeding behaviors at 5-6 months. If your male is also being anxious, bobbing its head – these might be the signs of a sexually mature bearded dragon. However, females might also turn black during a breeding season, but this is more unusual. 
Breeding behaviors should start roughly a month after the end of brumation. Brumation is a winter shutdown, when bearded dragons become mostly inactive and eat little to nothing.
After the end of brumation, breeding behaviors should start with the beginning of spring. In this case, you can let your dragon roam the room so it can use this energy.
Reason number 3: Your bearded dragon feels threatened
If your bearded dragon’s beard turns black, but it also puffs it, then this is a sign of aggression. Your bearded dragon might be aggressive when it meets another bearded dragon and feels threatened. It can also be a sign that your bearded dragon doesn’t want to mate and wants to be alone.
What is more, your bearded dragon could see its own reflection in the glass of a tank, thinking that its another bearded dragon! If your bearded dragon sees its own reflection in the glass, it can also bob its head, wave its arm and turn its beard black. Try to cover the glass and see what happens.
Reason number 4: Your bearded dragon is stressed or sick
If there is something wrong with the setup, your bearded dragon might become stressed. This includes wrong setup, diet, lack of lights, lack of supplements and so on.
If your bearded dragon is turning black and is also lethargic, doesn’t eat much, there might be something wrong.
If you want to find out a potential cause of these problems, read this article and answer all the questions regarding your bearded dragon’s setup and diet. There, you will also find advice and answers on a correct setup, diet and supplements. It is also a good idea to see the vet if you suspect a serious issue.
Your bearded dragon might also be stressed if it is new to your home. It can blacken its beard to show attitude, so be patient. Your bearded dragon should become comfortable in its new home within 2 weeks.
Reason number 5: Your bearded dragon has stress marks due to stress or age
When your bearded dragon is stressed (due to lack of heat, light, attention, bad diet, small tank etc.) it can develop temporary stress marks. Stress marks are often scattered on the belly and beard, and can have a shape of lines, circles or ovals. If your bearded dragon is new to your home, it might be stressed. Stress marks can fade away after few days to a week.
This bearded dragon was severely malnourished and stressed
If your bearded dragon has stress marks all the time and they won’t go away, this might be normal, too.
This could be normal only in baby and juvenile bearded dragons, and these stress marks should start fading away with age. If your bearded dragon has always had these marks (if it’s a baby), these marks can start disappearing soon.
But only assume that your bearded dragon is fine if everything is set up correctly (tank size, lighting, substrate etc.). Your bearded dragon should also be pooping, eating and basking regularly.
Don’t assume everything is fine unless you are sure everything is correct with the setup and diet. Read these questions and answer them to find a potential issue or problem that could cause stress marks.
Reason number 6: Your bearded dragon wants attention
Some bearded dragons might turn their beard black to get attention. This might happen if your bearded dragon is bored and wants to come out to explore.
If your bearded dragon is eating, pooping and basking fine, this might be a reason. Try to spend more time with your dragon outside the tank. Find a list of fun activities and toys for your dragon here.
Reason number 7: Dark tail – your bearded dragon has a tail rot or broken tail
If your bearded dragon’s tail has darkened, this can be a sign of tail rot. There are few reasons why your bearded dragon’s tail can become black. One of the reasons is when a retained skin accumulates around the tail tip and compresses the blood flow.
Another reason might be a mechanical injury, cage mate attack or even hungry crickets attacking and biting on your dragon. Any cut can also cause infection, leading to tail rot.
With a tail rot, the tail will look dry. Sometimes, bearded dragon’s tail might also darken before shedding.
What is more, sometimes bearded dragon’s tail might be injured – and you might suspect a broken bone if something fell on the tail. With tail rot, the rot can spread higher in the tail, or it can dry and fall off by itself. In any case, take your bearded dragon to the vet for an X-Ray and probably removal of the tail tip if it’s infected. 
Always make sure there is no retained skin after shedding around the tail, limbs and eyes. Give your bearded dragons a bath two times a week. If there is darkening of the tail, soak it in a Betadine solution to prevent infection. And never keep males together.
After your bearded dragon has eaten (15 minutes), remove any bugs. Crickets might become hungry and bite your bearded dragon.
Also, never place branches too high in the tank, and make sure to secure any heavy accessories with a non-toxic aquarium sealant. There have been many cases when heavy accessories fell on a bearded dragon, causing injuries.
Reason number 8: Your bearded dragon will be pooping soon
In some bearded dragons, their beards darken few hours before they poop. This might sound strange, but it can happen in some bearded dragons.