Exotis ISSN 2398-2985

Reptiles

Lizard nutrition

Contributor(s): Vetstream Ltd, Lesa Thompson

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Introduction

  • One adaptation that has allowed lizards to colonize nearly all terrestrial (and some aquatic) habitats on earth is their variation in dietary preference. Consequently, their prime vulnerability in captive management becomes nutrition-related disease when the proper diet is not provided.
  • Lizards are commonly classified as herbivorous, insectivorous, carnivorous or omnivorous.
  • Though the differentiation between insectivorous and carnivorous may seem subtle, some species are so highly specialized to eat specific arthropods and gastropods that they refuse to eat and fail to thrive in captivity if offered any substitutes. Additionally, when fed proper whole animal meat diets, carnivorous lizards generally do not require supplemental ultraviolet lighting, whereas the great majority of insectivorous lizards do require routine ultraviolet light exposure, even when fed calcium-enriched or supplemented insect diets.
  • Just as there is no way to describe the basic lizard cage, it is impossible to generalize lizard diets.
  • Each species has specific dietary requirements and variations in food availability in their native habitats that dictate dietary preferences on a seasonal or even monthly basis. For some, dietary needs change with age/class:
    • Carnivorous lizards (monitors, tegus) ingest other vertebrates (fish, reptiles, birds, and mammals) as their primary diet, but remain opportunistic and usually attempt to eat anything that moves and anything that will fit into their mouth.
    • Some carnivorous and omnivorous species may also eat carrion or may be cannibalistic.
    • Carnivorous lizards that are not fed whole animal meat products are more likely to develop nutritional disease.
    • Some herbivorous lizards are opportunistically carnivorous or insectivorous, which, with some species in captivity, may cause serious nutritional disease when animal protein is fed in abundance.
  • The ultimate paradox with some nutritional diseases in lizards, however, is that the causes of disease may have nothing to do with food. Temperature, humidity, landscape, water, infectious organisms (intestinal parasites, bacteria), and especially light (specifically ultraviolet light) are commonly factors in poor nutritional health despite the provision of proper diet. Thus, proper husbandry becomes the key to providing proper nutrition Lizard husbandry.
  • Nutritional requirements pertain to all lizards Nutritional requirements.
  • Feeding behavior, digestion, the absorption and assimilation of nutrients, and cellular physiologic activity are all somewhat dependent on temperature for all reptiles Lizard ingestive behavior:
    • The preferred optimal temperature zone (POTZ) and thermal gradient must be provided for each species to optimize the nutritional value of foods.
    • Improper humidity also impacts overall patient health and may lead to a decreased feeding response.
  • The quality and variety of food offered is important for all lizards:
    • Food items should be fresh or provided promptly after thawing if frozen.
    • Foods offered once to lizards should be disposed of and not refrozen or preserved and offered again.
  • Protein content and quality is generally met with whole animal diets and insects:
    • For herbivores, the entire protein requirements should be plant origin.
    • Good plant protein sources include: romaine lettuce, spinach, alfalfa sprouts, clover, dandelion, bean sprouts and bamboo shoots.
Print off the Owner Factsheets on Feeding your chameleon, Feeding your gecko and/or Feeding your lizard to give to your clients.

The importance of calcium

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Herbivorous lizards

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Insectivorous lizards

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Carnivorous lizards

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Further Reading

Publications

Refereed papers

Other sources of information

  • Wilson B (2017) Lizards. In: Exotic Animal Medicine for the Veterinary Technician. 3rd edn. Eds: Ballard B & Cheek R. Wiley-Blackwell. pp 95-135.
  • Donoghue S (2006) Nutrition. In: Reptile Medicine and Surgery. 2nd edn. Eds: Mader D R. Saunders-Elsevier, USA. pp 251-298.
  • Calvert I (2004) Nutrition. In: Manual of Reptiles. 2nd edn. Eds: Girling S J & Raiti P. BSAVA, UK. pp 18-39.

Reproduced with permission from Bonnie Ballard & Ryan Cheek: Exotic Animal Medicine for the Veterinary Technician © 2017, published by John Wiley & Sons.


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