Basic
Husbandry

of the
crocodile monitor
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What's the difference of owning wild caught vs captive bred? Wild-caught animals carry more parasites and pathogens, meaning a large vet bill at the start.  One is taking something out of the wild, thereby depleting a population of apex predators.  Almost 50% of the wild-caught animals die during the process of importation, most likely from stress, poor quarantine methods, and unhealthy shipping conditions.  Wild-caught are usually young adults and will not truly acclimate to close human presence.  Captive-bred animals are less likely to carry parasites and pathogens.  A captive-bred therefore has better health initially.  They are also more adaptable to people, and these animals are not taken from the wild, but are actually in addition to the natural population, promoting the survival of the species.  Overall, captive-bred animals are also more likely to become tame and are a better value in spite of their higher price.  One is also rewarding a breeder who has taken great pains and expense to promote a flagship of the lizard kingdom

Growth:
Hatchlings can measure 41cm-50cm (14in - 20in.). Growth rates can vary from 15cm to over 60cm (6in. to over 2ft) yearly depending on level of care and stage of development. Full grown adults reportedly have the potential of reaching lengths 4-5m (13-15ft), although none that size have been 'verified' to date.

Enclosure:
Enclosures should be high enough to allow for climbing and wide enough to allow for sufficient movement, basking opportunities, and multiple hiding spots (if animals are to be housed in a group). Sizes vary from one institution/keeper to another. An enclosure size of 2m x 2m x 2m (L x W x H) (6.5ft x 6.5ft x 6.5ft) should be considered the minimum for a sub-adult, 3m x 3m x 3m for adults up to 2m, and much larger for full grown adults.

Heat: Ambient temperatures 26C-32C (80-90F)

Basking Temps:
38C to 48C (100-120F)

Humidity: Minimum above 60%. Direct misting several times daily by hand. Automated misting systems recommended for drier areas. Humidity is very important to this species; skin conditions may result from lack of humidity..

Lighting: Most keepers and institutions utilize some type of basking light, either red reflector heat lamps or indoor/outdoor flood or spot lights which provide UV-B. Outdoor cages provide natural sunlight or UV-transmitting skylights are useful for indoor settings. Some suggestions for added lighting for indoor enclosures: Durotest Powertwist Vita-Lites® (or Philipps® Chroma 50) or Sylvania® 40 watt BL 40 black lights. Sunlamps are not recommended.

Water: A bowl for drinking. Some observers see them readily drink from misting systems. A soaking tub may become necessary if humidity cannot be maintained. The need to soak may indicate some dehydration.



Food: Mice, rats, chicks, quail. Additional foods: live minnows, bass, shrimp, hard boiled peeled eggs, bird of prey diet, turkey babyfood have reported as treats or supplements to regular feeding. Hatchlings: crickets, pinkie, or fuzzy mice for first meals every day. Juveniles: every other day. Adults: twice weekly.

Substrate: Dirt/sand mix, pea gravel, wood mulch. In general, the substrate should be able to retain a lot of moisture without creating a favorable environment for pathogenic bacteria and/or mold, as well as a soft drop-zone for lizards inclined to jump from high areas in the cage for whatever reason. 

Furnishings: Logs, large branches, (artificial) rocks, wooden platforms, dig boxes, and hide boxes. Crocs can be very destructive, so (artificial) plants, trees and other like furnishings should not be included.

Diseases: Cataracts have been reported in older males by some institutions- perhaps a result of some artificial lighting or too much direct sunlight. Fecal examinations conducted on freshly imported V. salvadorii reveal such enteric parasites as flagellates, mite ova, oxyurids, cestodes and strongyles. Under normal circumstances these do not seem to cause any significant health problems, although anthelmintics have been administered to the specimens at Gladys Portland Zoo as a precautionary measure. In recent years, there have been several reported mortalities in North American institutions. These deaths have been attributed to complications resulting from impacted eggs in females, bite wound infection , encapsulated stomach abscess,  unidentified brain lesion, and other causes.  At Ft.Worth Zoo while operating on an egg bound female several large liver abscesses were discovered.  (Colette Hairston Adams 1995) This animal died the next day. Liver cancer has been reported in a few instances by Mark K. Bayless, 1997.




Sexing: There seems to be no distinguishable difference between male and female outwardly. Best guesses range from size and shape of head to partially everted sex organs. None of these are 100% reliable. Testing for the amount of circulating testosterone in the blood has proven to be the most effective test; with males having about 10X more than females. Ultra sounds and x-rays can also be very decisive.

Introducing monitors to each other: Introductions should be done with a "howdy" period. This is where the animals get to smell and see one another from a mesh partition dividing the enclosure(s). A period of 2-4 weeks is usually sufficient based on observed non-aggressive behavior.
Related articles Ft Worth Zoo email Gladys Porter Zoo abstract Denver zoo email