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Monthly Archives: May 2012

Amphipods (Scuds, Side-Swimmers) as Food for Amphibians and Reptiles

Gammarus Roeselii (Scud)Hello, Frank Indiviglio here.  Like sowbugs (isopods, pillbugs), Amphipods are crustaceans that feature prominently in natural diets of many reptiles and amphibians.  They contain nutrients not found in insects, and are likely a rich source of calcium.  Several species are easy to collect and breed in captivity, but, unlike sowbugs, they rarely attract much attention from hobbyists (please see the article below for information on breeding sowbugs).  Whether you know them as Rock-Hoppers, Sand-Hoppers, Lawn Shrimp or any of the names above, one Amphipod or another likely makes its home near yours, and may be worth investigating as a food source for your pets.

Natural History

Amphipod diversity is astounding…over 7,000 species have been identified, and experts concede that they have no idea of the actual number in existence. 

Found from pole to pole, Amphipods reach their greatest abundance in colder oceans.  Most live in marine environments, but a number have colonized fresh water and land; of the known terrestrial species, 45% dwell in caves or other subterranean environments.  They range in size from 0.8 to 1.6 inches long, and may be omnivorous, carnivorous or herbivorous. Read More »

Green Iguana Care – Housing, Diet and Handling

Green IguanaHello, Frank Indiviglio here.  The Green Iguana (Iguana iguana) is truly a study in contrasts.  Captive-bred by the millions on farms in Latin America, the 7-inch-long hatchlings are widely considered to be suitable for novice reptile keepers.  Indeed, with proper care, they mature into one of the most impressive and responsive of all reptilian pets.  Yet these tropical lizards have very specific needs that must be met if they are to thrive, and their eventual size (4-6 feet) and potentially aggressive behaviors are serious considerations. 

Range and Habitat

The Green Iguana’s range extends from southern Mexicothrough Central America to Paraguay. They also inhabit Puerto Rico, St. Lucia and other Caribbean islands, and have been introduced to Florida and Hawaii (please see this article on Iguana-Raccoon Interactions in Florida). 

Green Iguanas are always found near water, into which they plunge when frightened. They are often associated with forested areas, so I was surprised to encounter large populations in Venezuela’s treeless llanos region; please see this article.

Behavior

Green Iguanas are ever-alert, and easily startled by noises, dogs and other threats. They vary greatly in personality – some become docile, while others remain wary of people.  

Frank with Green IguanaMales may become dangerously aggressive with during the breeding season (please see article below), and either sex may bite, lash out with the tail, or scratch.  The wound on my arm, pictured in the attached photo, resulted from a single flick of the tail (and my skin is generally described as “very leathery”!).  Please write in for information on safe handling.

Housing

Setting up the Terrarium

Enclosure size is a major concern.  Hatchlings will exceed 2 feet in length in their first year, and 3 feet by age 2.  Adults reach 4.0 to 5.5 feet in length, with males sometimes exceeding 6 feet.

Hatchlings may be started in a 30 gallon aquarium, but will need a 55 gallon tank within 12 months.  Once your lizard reaches 3 feet in length, a homemade or commercial cage will be necessary.  An enclosure measuring 6 x 3 x 6 feet tall will suffice for an adult; wheels should be added to allow for sun exposure.  Predator-proof outdoor cages such as modified bird aviaries are the ultimate in “luxury accommodations”.

Green Iguanas are highly arboreal and will be stressed if kept in enclosures that do not allow climbing opportunities.  Stout branches and wooden shelves should be provided.

If an “iguana proof” room is available, out-of-cage exercise time can add greatly to your lizard’s quality of life. 

Substrate

Cypress mulch has been used with success, but impactions due to substrate ingestion are possible.  Newspapers, washable cage liners or outdoor carpets are preferable.

Females without access to suitable nesting sites may retain their eggs; please see this article for information on captive breeding.

Light

Green Iguanas will not thrive without a source of Ultra-Violet B light.  Natural sunlight is best, but be aware that glass and plastic filter out UVB rays, and fatal overheating can occur very quickly. 

If a florescent bulb is used (the Zoo Med 10.0 UVB Bulb is ideal), be sure that your pet can bask within 6-12 inches of it.  Mercury vapor and halogen bulbs broadcast UVB over greater distances, and also provide beneficial UVA. 

Heat

The ambient air temperature should range from 82-95 F, with a basking spot of 95-100 F.  Incandescent bulbs should be used to maintain these temperatures.  A ceramic heater or red/black night bulb can be used after dark.

Humidity

Green Iguanas favor humidity levels of 65-75%, but must be able to dry off as well.  The terrarium should be misted as needed.  A reptile humidifier may be used in especially dry environments. 

A large water bowl should be provided for drinking and soaking.

Companions

Male Green Iguana during breeding seasonMales will fight savagely, and females may also battle for dominance.  Juveniles usually get along, but must be watched carefully as they mature.

Feeding

Strict attention to diet is essential if you are to succeed with Green Iguanas.  Nutritional deficiencies can develop quickly, and are difficult to treat. Young iguanas should be fed daily; 2 small meals are preferable to 1 large.  Adults can be fed every-other-day, or provided smaller daily meals.

Greens, Vegetables and Fruit

The majority of your iguana’s food – 60% or more – should consist of a variety of fibrous, calcium-rich vegetables such as kale, romaine, dandelion, bok choy, collards, mustard and turnip greens, beet tops and escarole; broccoli, peas, squash, beans, carrots, peppers and mixed frozen vegetables may be added in smaller quantities.  Spinach binds calcium and should be avoided.

Fruit should not comprise more than 10% of your iguana’s diet.  Bananas, pears, apple, figs, melons, berries, kiwi, peaches and others should be offered. 

Boiled brown rice or fiber-rich, sugar free cereals (i.e. Fiber One) may be given as a fiber source. This may not be necessary if a variety of fibrous greens are provided, but serves well as “insurance”.

Protein

In their natural environment, young Green Iguanas consume both insects and vegetation before switching to a plant-based diet as they mature.  While success has been had by using insects as a protein source for young iguanas, most keepers are better off relying upon legumes, such as boiled lentils or pinto, navy and kidney beans.  These should make up 5-10% of the diet until age one, after which time they can be used as occasional treats.

A number of commercial iguana diets are available.  While their long-term use as a sole diet has not been studied, adding some to your iguana’s salad should provide additional nutrients.

Supplements

Most meals provided to growing iguanas should be powdered with a Calcium source such as Zoo Med ReptiCalcium.  Reptivite or a similar vitamin/mineral supplements should be used 2-3 times each week.  The supplementation needs of adults vary; please write in for further information.

Health Considerations

Due to their size, Green Iguanas are sometimes allowed to wander at will about the home.  While a room that has been carefully set up for your iguana (please write in for details) can be useful, free-ranging iguanas present serious health and safety risks.  Chief among these are the potential for fires (dislodged lamps, etc.) and an increased risk of Salmonella transmission.  Please write in for further information. Read More »

Ant Control for Reptile and Amphibian Owners – Diatomaceous Earth

AntsHello, Frank Indiviglio here. Drawn by uneaten food, shed skins and other organic material, ants sometimes become pests around reptile, amphibian and invertebrate collections. As pesticides are harmful to humans and other creatures alike, eliminating ants in areas used by pets and people takes some care.  Today I’d like to highlight a substance that I used with great success in various zoos, and which works equally well at home – diatomaceous earth.

A Most Formidable Insect

Famed entomologist E.O. Wilson has demonstrated that ants “rule” many habitats, driving evolution and other processes to a degree that is hard to imagine.  What little work I’ve done with them has convinced me that they are, at the very least, extremely resourceful creatures. When working with Leaf Cutter Ants (Atta cephalotes) at the Bronx Zoo, I observed a dramatic increase in egg production shortly after empty nesting chambers were added to the colony’s enclosure – the workers somehow communicated to the queen that more space was available, and more bodies were needed. This likely holds true for other species as well – killing a few dozen workers will not reduce ant numbers but instead may set up a call for more eggs! Read More »

Senegal Chameleon Diet Study – Nutrition Influences Prey Choice

Jackson’s ChameleonHello, Frank Indiviglio here. The Senegal Chameleon (Chamaeleo senegalensis) has long been common in the pet trade, yet there remain significant roadblocks to longevity and breeding. I recently re-read a 1990 study on prey choice in this species. I then considered it in light of newer research that established a link between Vitamin D levels and chameleon basking behavior. I believe both contain important findings that may be applicable to many species.

“What, grasshoppers again”!

In the study that examined prey choice in Senegal Chameleons (J. of Herpetology: V.24, N.4: p.383), different groups of chameleons were fed solely on either Long-Horned Grasshoppers or House Crickets. Over a period of several days, those lizards feeding upon crickets showed a strong preference for grasshoppers, and those on grasshopper-only diets favored crickets.

I have also observed this in other chameleon species under my care at the Bronx Zoo, and in a variety of reptiles and amphibians. As long as the species is acceptable, novel prey usually causes a very strong feeding response. Indeed, zookeepers and hobbyists commonly say that captive herps “become bored” with crickets, mealworms and other staples. Read More »

Pet-Safe Cricket and Roach Control for Reptile and Amphibian Owners

Camel CricketHello, Frank Indiviglio here. Almost every zoo building in which I’ve worked was home to roach (2-3 species) and House Cricket populations.  In most, pesticide use was not an option. An older animal keeper whom I befriended let me in on his favorite insect pest control technique – the molasses trap.  He was content to let management wonder how he did such a good job so, out of respect for him, I did not share the secret until he retired. Then, for a time, molasses traps became standard in several zoo buildings. Molasses is also useful in outdoor traps, where it never fails to turn up a variety of interesting species. I’ll expand on that below as well.

Pesticide Problems

House Crickets, roaches and other escaped “feeder insects” can be problematic in private collections. In the damp basements favored by amphibian keepers, Spotted Camel Crickets (Ceuthophilus maculatus, please see photo) may also set up housekeeping. These unusual creatures are very interesting in their own right, and I’ve featured them, and a large African relative, in several exhibits. However, most folks find their size, appearance and jumping abilities quite unsettling (please see comments in the article linked below – insect fans will find them very interesting!). Read More »

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