Caring for Reptiles and Amphibians: Useful Foods, Medications and other Products from the Aquarium Trade – Introduction and Feeding Accessories


The Influence of Hobby and Food-Species Research

As compared to the aquarium hobby, the keeping of reptiles and amphibians in captivity is a relatively new development.  Far more time and research has gone into the development of products designed for fish and aquatic invertebrates than is the case for herps, and we know a great deal more about keeping and breeding them in captivity.  Also, commercially valuable species such as salmon, tilapia, clams and shrimp have generated a great deal of husbandry-oriented research, much of which has found application in the aquarium hobby.

Fortunately, the needs of many amphibians and reptiles parallel, and in some cases closely match, those of certain fishes.  Many of the fine products designed for aquarists are therefore of great value to reptile and amphibian enthusiasts.

Keeping Amphibians and Fishes Together

The Aquarium Fish Dish  is a valuable tool for those keeping African clawed frogs and newts along with fishes.

Fishes that feed at the aquarium’s surface and mid-water level nearly always consume blackworms and other live foods, as well as sinking pellets, before resident amphibians are even aware that it’s feeding time.  Live food specialists, such as dwarf African clawed frogs, rarely do well with fish for this reason, despite otherwise co-existing well with many species and making for an interesting tank.  The Fish Dish allows you to specifically target bottom feeding amphibians in mixed-species aquariums.

Limiting Choke Hazards

I came upon the idea of using the Cone Worm Feeder many years ago when raising axolotl and red-spotted newt larvae.  I fed them largely upon live blackworms, which always clump together, even when finely chopped.  I found that larvae of both species sometimes choked to death while trying to swallow the tightly-packed worm balls.

The worm feeder dispenses live worms individually, and has proven very useful to me in raising a wide variety of salamander larvae.  I use it with adult salamanders as well, especially the smaller species such alpine newts.

Certain fish medications work well with amphibians…please see my article:

Methylene Blue As A Treatment for Aquatic Reptiles and Amphibians

Titanoboa cerrejonensis, the World’s Largest Snake: Extinct Anaconda-Like Serpent Believed to Have Reached 43 Feet in Length and 2,500 Pounds in Weight


Well, the name says it all – Titanoboa!

Snake-oriented web sites will be alive this week with news of the discovery of fossils belonging to a snake of unprecedented size.  Writing in the journal Nature, researchers from the Smithsonian Institute and the University of Florida note that Titanoboa was larger than the contrived serpent that “tries to eat Jennifer Lopez in the movie Anaconda” (Ms. Lopez and company appeared at the Bronx Zoo when that movie was in progress, seeking technical advice.  I was a reptile keeper at the time, but, sadly for me, the powers that be declined to become involved!).

Colombia‘s Anacondas…now and then

An artist’s rendition of the huge beast casts it much like a very large anaconda.  Indeed, the giant is believed to have kept to Colombia’s marshy areas, home to modern-day anacondas.  Titanoboa roamed Colombia during the Paleocene Epoch, just after the extinction of the dinosaurs (approximately 65 million years ago).

Chasing Today’s Giants

There is only one reasonably reliable account of a modern-day snake measuring over 30 feet in length.  A reward offered by the Bronx Zoo for another stood uncollected for nearly 100 years.

I’ve done my level best to find a record breaking anaconda, and I like to think that she is out there somewhere.  The largest anaconda that I came up with was just over 17 feet long and weighed in at 215 pounds – no Titanoboa, but then again not an easy animal to wrest from the muck of a Venezuelan swamp either.  For the full story and some photos of myself and others with that snake, please see my article Hunting Anacondas in the Venezuelan Llanos.


Scorpions in Captivity – An Overview of Popular Species – Part 1


Emperor ScorpionAs is true for tarantulas, reptile enthusiasts (myself included) are often interested in scorpions.  Today I would like to provide an overview of these most ancient of animals (they were likely the first creatures to leave the sea for a terrestrial existence), with specifics concerning some readily available species to follow next time.

Please Note:  All scorpions manufacture venom and are capable of delivering a painful sting. Human fatalities are rare but not unknown, and the venoms of many are relatively unstudied.  Also, an allergic reaction is always possible…during my years at the Bronx Zoo I was often in contact with scorpion researchers….some reported relatively severe reactions from species not known to be dangerously venomous.

Unfortunately, the trade in scorpions is not well-regulated, and highly venomous species do appear from time to time (I’ll relate a personal experience in Part II of this article).  Purchase scorpions only from reliable sources, and be sure you can identify the species you are considering.  That being said, some of those best-suited to captivity are not dangerous, and make fascinating terrarium subjects.  Please check the legalities of scorpion ownership before acquiring one, as such is regulated in some areas.

Do not grab scorpions by hand, despite what you may see others do.  To move a scorpion, use a long handled stainless steel hemostat to gently grasp the telson (“tail”).  A bit of foam rubber should be secured to the tips to prevent the scorpion from being injured. 


Scorpions are classified in the order Scorpionidae, and, along with spiders, ticks and mites, in the Class Arachnida.  Nearly 2,000 species have been described (as opposed to 40,000+ spiders), ranging in size from .3 to 8.5 inches in length.  The 4 inch long Cetrruroides gracilis is the largest species in the USA, while the South African flat rock scorpion (Hadogenes troglodytes) is the world’s longest and heaviest.

Range and Habitat

Scorpions are found in tropical, sub-tropical and (less commonly) temperate regions of all continents except Antarctica, and are absent from New Zealand.  Various species are adapted to live in deserts, open forests, grasslands, caves and rainforests.  Some are quite at home around people, and may be found in overgrown fields, agricultural areas, gardens, parks and even within homes.

A surprising number thrive in quite cold climates, ranging as far north as Canada and southern Illinois in North America.  A feral colony of a small African species, introduced in produce shipments, is established in southern England.  In the USA, scorpions reach their greatest diversity in the southwest, where 60+ species may be found.


All are predacious, with most consuming soft-bodied insects but some specializing in land snails, sowbugs and other scorpions.  Larger species may take frogs, lizards, shrews and other sizable animals on occasion.


All scorpions thus far studied give birth to live young, and a number are parthenogenic.  Females typically carry the soft, relatively defenseless young on their backs for a time.  Many species feed their offspring with shredded insects…in some the young are totally dependant upon their mothers for food and will perish if separated too quickly.

In contrast to most of their spider relatives, certain species, including the popularly kept emperor scorpion, are quite social and may be housed in colonies.


Scorpion venoms are not well-studied, but thought to be quite complex.  Some that have been analyzed have yielded compounds with potential medicinal value.  Most seem to be neurotoxic in nature, but cytotoxic varieties are known as well.

The larger scorpion species are generally not dangerous to people, while some of the very small ones have caused fatalities.  Most of the 25-30 species thought to be capable of delivering serious stings are classified within the Genera Centruroides, Androctonus and Tityus.  However, as we have limited knowledge of scorpions in general, all should be treated with caution.  As mentioned, the possibility of allergic reactions to even weak venoms is always a possibility.  In all cases, small, straw-colored scorpions from the Middle East and North Africa should be avoided.

Scorpions in Captivity

At least 15 species are well-established in captive breeding populations, and many others are regularly available.  Fortunately, one of the largest and most interesting, the emperor scorpion, is also quite benign.  It lives well in groups, and females are surprisingly attentive to their young.  Next time I’ll write about the care of this and other popular species.

A short introduction to scorpion ecology, along with a diagram of their body parts and photos of common species of the American Southwest, is posted at:

Spitting Cobras (Family Elapidae, Genus Naja): New Research and Personal Encounters


A recent article (Jan. 2009) in Physiological and Biochemical Zoology has shed light on why spitting cobras nearly always hit the eyes of whatever creature they are aiming for, be it secretary bird (a predator), gnu (a trample hazard) or person.

Perfect Aim Not Needed

Utilizing high speed photography and EMG tests, researchers established that the snakes contract their head and neck muscles just before ejecting venom.  The contractions rotate the head and jerk it sharply from side to side, so that the venom forms a complex geometric spray pattern as it approaches its target.  As long as aimed in the general direction of the face, the venom contacts the adversary’s eyes nearly 100% of the time.

Keeping Zookeepers on Their Toes

I have worked closely with several types of spitting cobras.  Like many Elapids (cobras and their relatives), they are alert and quick-moving, and seem, at least on the surface, to be quite intelligent.  These traits, combined with their ability to both bite and “spit”, renders them quite a handful in captivity, and they provide much fodder for zookeepers’ tales.

Perhaps He Thought They Needed Exercise?

In one very bizarre incident from my Bronx Zoo days, a visitor held his son up so that the child could kick in the glass of an exhibit housing 3 black-necked spitting cobras (Naja nigricollis)!  As might be expected, the breaking glass caused a great deal of agitation to both the snakes and some of the other visitors…I say “some of” because nearly as many people were pushing towards the exhibit as were running away (those wacky New Yorkers!).  Fortunately, all emerged unscathed, and the snakes were recovered quickly.

Cobra Hunting to Start the Day

Another zoo adventure began when, still bleary-eyed after a few mugs of espresso very early one spring morning, I discovered that 3 red spitting cobras (Naja pallida) had vacated their holding cage overnight.  The ancient plastic goggles I used around spitters were fine for exhibit work, but rendered me nearly blind in the dim, cluttered recesses of the reptile house’s basement and storage areas.  Lifting the goggles briefly to peek under something was terrifying, but so was leaving them on and seeing only unidentifiable shadows.

One colleague, goggles perched on his forehead, spied a snake and grabbed it with tongs, neglecting to lower the goggles in the excitement.  Fortunately, the trapped serpent vented its wrath by biting the tongs, and not by spitting at my partner’s face!  After a few sweaty, suspense-filled hours, all 3 snakes were re-captured…whereupon I ordered new goggles!

I’ve also had run-ins with the spitting cobra’s much larger relative, the king cobra…please see my article A Close Call With a King Cobra for more cobra tales.

Image referenced from Wikipedia, first published by LA Dawson, and shared under the Creative Commons Share Alike-2.5 License.


Feeding Captive Savannah Monitors (Varanus exanthematicus) and Black and White Tegus (Tupinambis merianae): Zoo Med’s Canned Tegu and Monitor Diet


Browsing the pages of Herpetologica and other journals over the years, I several times came across field studies indicating that certain populations of savannah monitors consumed diets composed entirely of invertebrates.  In certain seasons, the lizards gorged on either locusts or land snails exclusively for months on end.  When some captives fed largely upon rodents showed evidence of kidney and liver damage and intestinal impactions, articles in popular magazines began calling for insect-based diets.

Canned Diets

Savannah monitors may approach 5 feet in length, and thus an insect-based diet is difficult to arrange…thousands would be needed weekly in some cases.  Zoo Med’s Canned Tegu and Monitor Diet provides a handy solution.  Formulated with these lizards in mind, it is readily accepted by most individuals.

After reading the aforementioned articles, I took a moderate position as regarded the savannah monitors under my care in public collections, using canned food as 60-75% of the diet.  I supplemented the food of adults

once weekly with vitamin/mineral powder  and that of juveniles 3-4 times weekly.

Invertebrate and Vertebrate Food Items

The easiest way to supplement canned food without using mice is to establish a breeding colony of Madagascar hissing roaches (even the well-armored adults are readily accepted) and nightcrawlers.  Crayfish, if available to you, are a great monitor food.  Other useful food items are land snails (available in seafood markets), tomato hornworms, hard boiled eggs (in moderation, i.e. once monthly) and canned grasshoppers , silkworms  and snailsPink and fuzzy mice (these are preferable to adult mice and rats) may be offered every 10-14 days.

My Observations of Wild Black and White Tegus

My observations of black and white tegus in Venezuela leads me to believe that, at least in llanos habitat, these lizards consume far more large insects, turtle eggs and frogs than rodents.  Mammals are taken when available, mainly as carrion or unearthed rodent nests.

I have kept tegus for lengthy periods on rodent-based diets but now counsel more variety…I suggest feeding as described above, but with canned food comprising a smaller portion (i.e. 25-50%) of the diet, and rodents, preferably pink and fuzzy mice, being offered once weekly.  If your tegu will accept whole fish (i.e. large shiners), use these in place of mice.

An interesting article on savannah monitor natural history and diet in the wild is posted at

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