Why Leopard Geckos Open And Close Mouth (Gaping)

Leopard geckos are expressive creatures, and they use many forms of body language to express themselves.

A common behavior seen in leos is opening their mouth real wide, also known as “gaping.”

Those with little experience with reptiles may be alarmed at this behavior because they do not know what it means, and they’d be right to be worried.

Gaping in leopard geckos may signify aggression, overheating, metabolic bone disease, or a respiratory illness. A leopard gecko will also display this gaping behavior if it is choking or has food stuck in its throat. 

Gaping is a normal behavior in leopard geckos and is usually not a cause for concern except in the cases of choking, metabolic bone disease, or a respiratory infection.

Read on for more information on the causes of gaping, including when you may need to seek veterinary care.

leopard geckos opening and closing mouth

Causes And Solutions For Leopard Geckos Opening Mouths

Gaping Because Of Aggression

Aggressiveness in leopard geckos is not common, but if they have not been handled frequently, they may show signs of aggression.

A leo may also be more aggressive when you first bring it home because it is high alert in its new environment.

You may notice your leo gaping when you approach it, which means the reptile is signaling to you it does not want to be bothered.

In addition to gaping, a leopard gecko may also hiss or make a squeaking noise if it feels threatened for any reason.

This is one of the completely normal communicative behaviors expressed by leos, and it is not a cause for concern.

Gaping Because of Overheating

Leopard geckos are crepuscular reptiles, which means they are more active in the hours between dusk and dawn.

Leos do not typically bask since they are not very active during the day, but they still need warmth in the form of heat lamps or heat mats.

If you notice your leo constantly gaping or spending most of its time on the cool end of the enclosure, your reptile may be getting too hot.

In the same way, a dog pants when it gets overheated, a leopard gecko’s natural behavior will be to open its mouth in an attempt to cool itself off.

A variety of reptiles will keep their mouths open when overheating.

Use a thermometer to check the tank temperatures to see if they are too high. 

Temperatures on the warm end of the enclosure should be between 90-94° degrees Fahrenheit (32° C). 

The cool end of the enclosure should be closer to 75° degrees Fahrenheit (24° C).

Learn all about leopard gecko temperatures with our complete guide.

It is also a good idea to check the thermostats on your heat sources. 

A shorted wire or other malfunction may cause the thermostat to have an incorrect temperature reading.

If you suspect the enclosure is too hot for your leo, remove the reptile from the enclosure while you work to solve the problem. 

If a leo is exposed to extremely high temperatures for long periods, it will suffer a heat stroke and possibly die, so this is time for some reptile rescues.

Improper temperatures in a leo’s enclosure are the source of many health issues. 

Monitor temperatures in your lizard’s enclosure frequently to make sure they are in the optimal range.

Gaping Caused by Metabolic Bone Disease

Metabolic bone disease is caused by a lack of calcium in a leopard gecko’s diet.

When a leo suffers from a calcium deficiency, its body will pull calcium from its bones. 

This leads to irreversible and crippling bone deformities, softening the bones in the spine and jaw, lethargy, the inability to stand, and paralysis.

As the jawbones begin to soften, a leo may start gaping and breathing heavily.

There is no cure for metabolic bone disease, and it often leads to death. 

While there is no way to reverse the effects, if the disease is caught in the early stages, calcium supplementation may slow the progression.

If you suspect your leo is suffering from metabolic bone disease, you should seek veterinary care right away. 

The illness is very painful for the lizard, and there is no reason to prolong its suffering.

To prevent metabolic bone disease, add a calcium powder supplement powder to your leo’s food. 

This is done by lightly dusting the feeder insects before each mealtime. 

Choose a calcium supplement with vitamin D3 added, as D3 helps the gecko’s body properly absorb the calcium.

Gaping Caused by a Respiratory Illness

Low temperatures and high humidity will lead to respiratory illness in leopard geckos.

Symptoms of a respiratory infection include:

  • Lethargy
  • Lack of appetite
  • Weight loss
  • Bubbly saliva
  • Clogged nostrils
  • Increased blood pressure
  • Open-mouth breathing (gaping)

Use a hygrometer to check the humidity levels in your leos enclosure. 

Ideal humidity should range from 30%-40%. 

Higher humidity levels not only lead to respiratory illness, but it causes your leo undue stress.

To lower the humidity level in your leo’s tank, use a mesh tank lid for better ventilation and remove any live plants in the enclosure. 

You should also reduce the size of the water dish, and if you are using a loose substrate, you should switch to something solid such as tile or paper towels.

You should also use a thermometer to make sure the temperatures in the enclosure are not too low. 

Leopard geckos are used to cooler nighttime temperatures between 67-74° degrees Fahrenheit (23° C). 

If tank temperatures are consistently lower than this, you will need to make adjustments.

Ensure your heat sources are working correctly, and check your thermostats to ensure they are not malfunctioning.

If you suspect your leo is suffering from a respiratory infection, you will need veterinary care for proper diagnosis. 

Treatment of a respiratory infection usually requires antibiotics and probiotics.

Gaping Caused by Choking

If your leo is gaping after eating a larger insect, this is a sign of food stuck in the throat or choking. 

If the gaping is accompanied by your leo shaking its head, it is likely attempting to regurgitate its food.

The insects you feed to your leo should be no larger than the space between its eyes to avoid choking hazards. 

The insects you are providing to your leo may be too large for it to handle.

Mealworms may also pose a choking hazard due to their tough exoskeletons, which are harder for a leopard gecko to chew and digest. 

Too many mealworms in your leo’s diet may also lead to impaction. 

An adult leopard gecko should only have a couple of mealworms once per week, and you should never feed mealworms to baby geckos.

A loose substrate mixture may also lead to choking if your leo accidentally ingests any of it, so you may want to consider switching to reptile carpet, tile, or newspaper as a substrate instead.

Always provide your leo with fresh, clean drinking water, so it can wash its food down properly.

If your leo is choking and struggling to breathe, you need to seek emergency veterinary care to remove the obstruction.

For more help with feeding, check out our recommendations for leopard gecko feeding schedule including several handy charts.

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