Monitor lizards of the Varanus genus have long been popular among reptile enthusiasts. As herp-keeping has advanced, captive care and breeding have been refined. While aspects of monitor care, such as housing, can be troublesome with larger species, it is still fairly straightforward: provide your animals with as much space as possible without compromising functionality or security. Feeding, however, leaves many questions unanswered, such as what to feed them, how much, how often, and what about supplements. While current publications on monitor husbandry tend to be quite acceptable, the data in older books is likely outdated. Additionally, monitors are a wildly diverse group of animals, with individual species having specific dietary requirements. This article compiles data accrued by experts over the past years. Monitor nutrition is a highly debated subject, and while many will agree that the insight provided below is proper, some will surely disagree with my recommendations. Be sure to carefully research the need of the specific type of monitor you are keeping. Some species have very specific dietary requirements, while others will eat nearly anything placed before them.
Understanding the Savannah Monitor's Natural Diet
In the wild, Savannah monitors are opportunistic carnivores, consuming insects, invertebrates, small reptiles, amphibians, carrion, and small mammals. Variety and balance are key to a healthy monitor. Recent studies have shown that presumed rodent eaters such as savannah monitors, actually consume mostly termites, millepedes, and scorpions. Hatchlings and juveniles are primarily insectivores in the wild but in captivity can be taught to eat other foods as well such as Mazuri carnivore mixed with insectivore chow.
Essential Food Items for Savannah Monitors
Insects and Invertebrates
In the wild, the staple diet of many monitor species is insects and other invertebrates. Crickets, dubia roaches, giant mealworms, and earthworms should make up the bulk of the diet for hatchlings. These should be gut-loaded to provide additional nutrients. Crickets, mealworms, waxworms, and roaches should be considered required items in the monitor diet.
Commercial Diets
Commercial monitor and carnivorous lizard diets can be categorized here as well. These diets are formulated to be complete and balanced, but should not be relied upon as a sole source of nutrition. Mazuri makes amazing diets for monitors I tend to not use pre made diets for my large lizards because they contain preservatives, additives and are in my opinion not natural and enriching enough for the animals. They are great to use as variation but not so much as staples
The Rodent Debate
The debate over whether or not to feed rodents to captive monitors is a heated one. In all likelihood, there is probably not a right or wrong answer. For many monitor keepers, watching their mini-dinosaurs hunt down and devour a live mouse is all part of the thrill. Mice and rats are generally considered to be too high in fat for most captive, exercise-deprived monitors. Keepers who choose to raise their monitors on a rodent-only or mostly rodent diet should be encouraged to avoid unweaned mice, as they have little or no calcium, and are fairly deficient in other vital nutrients. It should be noted that rodents are not a completely bad food source. In fact, they are an important part of a balanced diet.
Read also: Weight Loss Journey of Savannah Guthrie
Pre-Killed vs. Live Rodents
It is widely accepted to feed only pre-killed rodents to monitors. Live mice and rats can easily injure the animal they are intended to feed, resulting in lacerations, infections, or abbesses.
Alternative Diet Options
Quite a few years ago, keepers and animal nutritionists at the San Diego Zoo were experimenting with non-rodent diets for their larger monitor species. The exact, original recipe is not really known, but it is widely accepted that it contained nothing more than raw, ground turkey, eggs, steamed bone meal (as a source of calcium), and multivitamins.
Ground Turkey and Egg Mix
I recommend mixing one pound of raw, ground turkey with two raw eggs including the shells. The steamed bone meal is easily replaced by one heaping tablespoon of a high quality calcium/vitamin supplement designed specifically for reptile use. Mix this well, and feed your lizard whatever it will consume in a few moments. We have had tremendous success (as did the San Diego Zoo) with this diet, and provide it to all of our monitor and tegu species regularly.
Foods to Avoid or Limit
Foods designed for other types of animals (or humans) should be avoided or fed sparingly. These include cat and dog foods, hot dogs, and red meat. Fatty foods such as mice, rats, chicken, beef and turkey should be fed less frequently due to the risk of obesity, fatty liver disease and organ failure
Supplementation
I am of the opinion that growing monitors benefit greatly from the use of calcium and vitamin supplements in their diets. Some argue that if fed a varied diet of whole animal prey, monitors will not face any related health issues. Baby and juvenile monitors should have their food dusted with a high quality calcium/vitamin D3 supplement at every feeding. In conjunction with a suitable source of full spectrum lighting, these supplements will allow for proper skeletal growth and muscle development. In addition to the calcium supplement, a multivitamin is highly recommended. This should be in the form of a powder that is designed specifically for reptiles.
Read also: Water Monitor Feeding Habits
Feeding Schedule and Diet Progression
Hatchlings should be fed every day with a strong focus on gut loaded insects. Small amounts of boiled or cooked egg whites and small amounts of fish can be offered as well to round out the meal and offer variety.
Savannahs under 2 years old should still be fed 3-4 times a week until they reach sexual maturity and roughly adult size. Cooked or boiled egg whites, fish pieces, earthworms, dubia roaches, giant or super mealworms, crickets, and other insects should continue to be a bulk of the diet.
Adults should be fed 1-2 times a week depending on their body condition. The bulk of an adult Savannah monitor's diet should consist of large insects. Low fat items such as egg whites, crayfish and fish can all be offered as well. Pieces of cooked chicken or small mice can be occasionally offered as a treat for enrichment as well as training in some individuals. Obesity is a common problem in Savannah monitors and food should be fed as meals when adulthood is reached rather than constant supply.
Comprehensive Food List
This is a list of meats I personally feed my 3 monitors and my tegu. I came up with this list with the help of my vet, the vet at my local zoo, and my biology department at my school. Keep in mind the following when using these as guidelines
Mammalian Meat
Rabbit, goat, squirrel, venison, bison, lamb, pork (treat), beef (treat)
Read also: Ackie Monitor: Diet and Care
Avian Meat/Poultry
Duck, goose, quail, pheasant, Guinea fowl, chicken (treat), turkey (treat), pigeon
Fish Fillets
Salmon, sea bass, blue gill, tilapia, cod, grouper, catfish, snapper, sunfish, perch, other freshwater fish
Other Seafood
Octopus, squid, clam, oyster, lobster, scallops, cuttlefish
Whole Fish (frozen Thawed)
Sardines, herring, trout, lake smelt, silversides, capelin
Whole Crustaceans
Blue crab, crayfish, shrimp, krill
Whole Mammals (frozen)
Rats (rarely), mice (treat), rabbit kits, Guinea pigs (treat), hamster
Whole Birds (frozen)
Quail chicks, hen chicks, ducklings, goslings, turkey chicks, button quail
Miscellaneous Food
Frog legs, quail egg, duck egg, chicken egg, snail
Insects
Roaches (staple), locusts (staple), crickets, mealworms and super worms (treat), Phoenix worms, horn worms, silkworms, wax worms (treat), night crawlers and butter worms (treat)
Live Feeder Fish
Swordtails, mollies, platies, guppies, shiners
Organs (treats)
Hearts, livers, kidneys
Pre Made Food
Mazuri monitor diet, mazuri crocodile chow
Important Considerations
- Know the Monitor's Natural Diet: Some monitors like my savannah monitor are strict insectivores in the wild and should primarily be fed insects.
- Breed Live Feeders: I breed all the fish and insects I give my monitors, all are gut loaded and any bought from a pet store (only in emergencies) are quarantined before being fed off.
- Source Food Carefully: All the meats and fish are either from Whole Foods, the farmers market, local butchers shop, or local seafood markets. Frozen animals come from my friends farm. All are hormone, cruelty, and pesticide free.
- Establish a Feeding Schedule: My older monitors (Nile and ornate) eat every 2-3 days whereas my young savannah monitor eats daily.
- Avoid Live Feeding Mammals and Birds: Mammals and birds are more consciously âadvancedâ and are therefore not recommended to feed alive. Mammals and birds can also seriously injure your monitor when being hunted down.
- Avoid Fatty Foods: fatty foods such as mice, rats, chicken, beef and turkey should be fed less frequently due to the risk of obesity, fatty liver disease and organ failure