Lizards exhibit a remarkable range of dietary habits, reflecting their diverse habitats and evolutionary adaptations across nearly every continent. There is no single answer to what lizards eat, as their diet varies significantly by species, life stage, and the food sources available in their environment. Understanding these differences is fundamental to providing appropriate care, especially for captive lizards.
Understanding Lizard Dietary Categories
Lizards generally fall into three main dietary categories: herbivores, carnivores, and omnivores.
Herbivores primarily consume plant matter, including various vegetables, fruits, and flowers. Carnivores are meat-eaters, with many being insectivores that subsist mainly on insects and other invertebrates. Some larger carnivorous species may also prey on small mammals or other reptiles. Omnivores maintain a diet that includes both plant and animal matter. Many species commonly kept as pets are omnivores.
Specific Diets of Popular Lizards
Bearded dragons ( Pogona vitticeps ) are omnivores, consuming a varied diet of insects, vegetables, and some fruits. Juveniles typically require a higher proportion of insects (around 50-80%) to support their rapid growth, with the remainder being plant matter. As they mature, their diet shifts to primarily plant-based (about 80% plants, 20% insects). Suitable insects include crickets, dubia roaches, and soldier fly larvae. Good plant options are collard greens, mustard greens, and various squashes.
Leopard geckos ( Eublepharis macularius ) are insectivores, eating almost entirely live insects. They cannot digest plant matter, fruits, or vegetables. Common food items include crickets, mealworms, silkworms, and dubia roaches. Fatty insects like waxworms and superworms should be offered sparingly as treats.
Green iguanas ( Iguana iguana ) are herbivores, primarily feeding on leaves, flowers, and fruits in their natural habitats. In captivity, their diet should mainly consist of dark, leafy greens such as collard greens, mustard greens, and dandelion greens. Fruits like mangoes, papayas, and berries can be offered in moderation, making up no more than 10-20% of their diet. Animal-based proteins are not suitable for green iguanas and can lead to health issues.
Chameleons are primarily insectivores, eating live insects such as crickets, mealworms, roaches, and waxworms. Some chameleon species, like veiled chameleons, may also occasionally consume small amounts of plant matter, including leaves and flowers. Providing a diverse range of insects is important for a broad spectrum of nutrients.
Key Nutritional Needs and Supplements
Lizards require particular nutrients for their health. Calcium and vitamin D3 are important for bone development and preventing metabolic bone disease (MBD). MBD results from an imbalance in calcium and phosphorus, often seen when insects are not properly supplemented. Lizards also need various other vitamins and minerals, including vitamin A and E, which support immune function and overall well-being.
Supplements are often necessary for captive lizards. Live feeder insects should be “gut-loaded” by feeding them a nutritious diet for at least 24-72 hours before being offered, increasing their nutritional value. Dusting feeder insects or plant matter with calcium powder (often containing vitamin D3) and a multivitamin supplement is a common practice.
Foods to Avoid Feeding Lizards
Certain foods are unsuitable or toxic for lizards. Avocado contains persin, a harmful toxin that can cause lethargy, loss of appetite, and even death. Citrus fruits can cause gastrointestinal upset due to their high acid content. Iceberg lettuce offers minimal nutritional value and should not be a primary food source.
Wild-caught insects should be avoided as they may carry pesticides, parasites, or be toxic, such as fireflies. Dairy products are unsuitable because lizards lack the enzymes to digest lactose, potentially leading to digestive issues. Foods high in oxalates, like spinach and kale, should be fed sparingly as they can hinder calcium absorption.
General Feeding Guidelines for Captive Lizards
A balanced and varied diet is crucial for captive lizards. Feeding frequency varies by species and age; juveniles typically require more frequent meals, often daily, to support their growth, while adults may be fed every other day or a few times a week. Portion sizes should be appropriate, with feeder insects generally no larger than the space between their eyes.
Fresh, clean water should always be available, provided in a shallow dish or through misting for species like chameleons that drink water droplets. Offering a rotation of different feeder insects and plant types helps ensure a broad spectrum of nutrients. Proper food preparation is important, including washing produce to remove pesticides and cutting food into small, manageable pieces to prevent choking. Live prey encourages natural hunting behaviors, but commercially prepared foods can also be part of a varied diet.