Iguanas are large lizards and tend to gain weight as they grow and age. After maturity, iguanas tend to keep the same weight and rarely become fat. But sometimes, iguana can start losing weight due to different reasons. In this post, we will discuss reasons why iguana might be losing weight, healthy iguana weight and signs of weight loss in iguanas.
Iguana weight chart
| Age of iguana | Iguana size | Iguana weight |
| 0-6 months | 15-25.4 cm (6-10 inches) | 60-90 grams |
| 6 months | 18-45 cm (7-17.7 inches) | 300 grams |
| 12 months | 45-69 cm (17.7-27 inches) | 300-600 grams |
| 2 years | 69-95 cm (27-37 inches) | 600 grams-1.5 kg |
| 3 years | 70-110 cm (27.5-43 inches) | 1.5-2.5 kg |
| 4 years | 85-135 cm (33-53 inches) | 2-3 kg |
| 5 years | 110-150 cm (43-59 inches) | 3-6 kg |
| 6 years | 120-170 cm (47-67 inches) | 4-7 kg |
| 7 years | 125-180 cm (49-70.8 inches) | 5-8 kg |
| 8 years | 137-190cm (54-74 inches) | 5-10 kg |
Your iguana is not likely to start gaining weight quickly straight away. As it grows, it will gain more weight due to building of muscles and bones. Some iguanas might start off skinny and gain a lot with time.
Please note that the numbers in this table are for the guide only, and every iguana grows at its own rate. But if your iguana’s weight is much lower than the range in this table, then it’s probably skinny. Your iguana’s tail might also be chipped or partly broken, decreasing the weight.
Signs of weight loss in iguana
Signs of weight loss in iguana include protruding ribs, thin tail, skinny limbs. The skin is also likely to be hanging around the head and legs. The spine will be sticking out in very skinny iguanas. Head will look small. In iguanas of healthy weight, the body looks ‘full and plump’, with skin on tight.
Another way to monitor iguana’s weight is to get kitchen digital scales like this. They should weigh to the nearest gram (around 0.04 oz). It is better to get larger scales to accommodate an iguana, as well as those that support up to 10 kg (22 pounds).
How often do iguanas need to eat?
Iguanas need to eat every day. Adult iguanas should have the main meal in the morning, and can have a snack towards the middle of the day. You can feed hatchling and baby iguanas twice a day, and offer a snack. Offer as much salad, vegetables, flowers and other greens as your iguana can eat.
Now, let’s discuss the reasons why your iguana might be losing weight.
Reason #1: Parasitic infection
Your iguana might be suffering from a parasitic infection, which can cause poor appetite, lethargy and weight loss. Your iguana might excrete different stools (smell and appearance) when infected with parasites.
With some visible parasites, you will be able to see them in the poop. But not all parasites are visible. Internal parasites include ringworms, pinworms, hookworms and protozoa.
If you suspect that your iguana is infected with internal parasites, take its stool to the vet. The vet will perform a fecal test. Place the poop in the bag, close it and take for the testing with 12-24 hours. Do not freeze.
Reason #2: Your iguana is gravid (or egg-bound)
If your iguana is gravid, she will be refusing to eat. This will often happen towards the end of her pregnancy. You will be to tell that your iguana is gravid if her belly looks distended despite the fact that she’s not eating much. She will also be digging and restless. She might lose the weight around her tail and limbs.
If your iguana is a female and is around 2 years old, she might become gravid without mating with a male. She will then lay infertile eggs. You must prepare the laying box as soon as possible so she can lay eggs.
One of the most serious issues with gravid iguana females is that they might not lay all the eggs. This causes egg-binding. If an iguana becomes egg-bound, her health will decline and can even kill her (if there has been rupture of follicles or eggs, causing inflammation).
This can be all caused due to different reasons, including very large eggs, bladder problems and more. That is why it is very important for you to take your iguana to the vet to have an X-Ray scan. Take her to the vet after you think that she laid all the eggs.
Read all about iguana breeding and laying eggs in this post.
Reason #3: Your iguana is suffering from digestive issues
Your iguana might start losing weight if it has digestive issues. These can include issues with liver, pancreas or stomach.
One of the problems that can cause your iguana to lose weight is diabetes – iguana will be eating same amounts of food, but losing weight (it can also be drinking more than usual).
What is more, your iguana’s stomach might be full of gases, not letting it eat more and leading to weight loss. Liver and renal issues might also get severe and lead to wasting of the body.
If your iguana is suffering from any health issues, you should notice more than one symptom. Keep an eye on your iguana and take it to the vet if you suspect an illness.
Reason #4: Improper diet
Your iguana might be losing weight if there are mistakes in its dietary choices. This includes feeding too little. Make sure to offer as much food as your iguana can eat – especially when it is growing. Your iguana is likely to stop eating when it is full.
Another mistake might be when you are feeding too many goitrogenic or high oxalate foods. Goitrogenic foods in large quantities disturb absorption of iodine by the body, causing iodine deficiency and thyroid issues.
Foods high in oxalic acid bind the calcium and interfere with its absorption! This can cause calcium deficiency over time and body wasting if you offer too much of these foods regularly.
Find the list of staple, goitrogenic and high oxalate foods in this post.
Reason #5: Your iguana is impacted
If your iguana is impacted, it will start losing appetite and might have problems with pooping. Your iguana might also have a full belly and become lethargic.
But some iguanas that are initially impacted will still eat normally, making it go unnoticed until the impaction becomes serious. Pooping frequency and contents will say a lot of iguana’s health.
Make sure to never use loose substrate for iguana’s tank and never leave small objects or loose fibers, hair and even clothing pieces around your iguana. Your iguana will try to eat everything that is sees. Some small objects might pass through the digestive tract, but might also get stuck.
Reason #6: Your iguana’s cage temperature is too low
If the temperatures in iguana’s cage are too low, your iguana won’t be able to digest the food properly. Its digestive tract also won’t be working smoothly, causing fecal masses to gather in the intestines.
This can not only lead to poor appetite, but also to other digestive tract issues. Make sure that the temperatures in the tank are optimal. There must be a cool spot for your iguana to move to when it’s too hot. You must also allow temperatures to drop lower at night time.
Read all about optimal lighting and heating for iguanas in this post (will open in a new tab).
Reason #7: Your iguana is sick
If your iguana is sick, it might start losing weight. One of the major issues include renal failure, when your iguana’s health starts to decline. Your iguana might be still eating, but will be losing weight.
Other problems include the Metabolic Bone Disease (MBD), due to calcium and/or vitamin D3 deficiency. Your iguana will be declining slowly, and it will take at least few months of improper care to develop a deficiency and visible signs.
Signs include swollen limbs (do not confuse with weight gain!), soft jaw and lethargy. At late stages, your iguana will be twitching, and will not be able to eat due to the painful jaw.
With time, the consequences of MBD will be irreversible. Always have UVB lighting in iguana’s cage/room, and make sure to replace UVB lights at least every 6 months. This is because the bulbs/fixtures stop emitting UVB light, without it being visible to you.
Other problems might include respiratory infection, stomatitis (mouth rot that makes eating painful) etc.
Reason #8: Breeding season
Apart from females going off the feed during the pregnancy, males can also do that during the breeding season. The breeding season often starts during the summer and last few months when your iguana reaches sexual maturity (around 2-2.5 years old).
Healthy male iguana that will be eating much less during the breeding season shouldn’t lose weight if it was healthy before. But sometimes, when conditions are very good, the breeding season might extend greatly.
In this case, your iguana will be still eating much less and might lose weight. In this case, try to stop the breeding behavior by manipulating temperatures and light cycles.
To sum up on weight loss in iguanas
To sump up, always address the underlying issue, because weight loss is most often caused due to other health issues and diseases. Always think about recent changes and the reasons that could cause the weight loss in your iguana.
After treating your iguana, it should start eating normally and gain the weight slowly. If your iguana is losing weight because it is not eating, you will benefit from reading this post.