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Halloween Creatures – Orange Crabs, Ghost Frogs, Vampires, Goblins…

Gluvia dorsalisHerp and invertebrate enthusiasts are never at a loss for frightening, even “ghoulish” (to “regular” people) stories. With Halloween just around the corner, I’d like to highlight some creatures whose names or habits associate them with this holiday.  Some, such as Thailand’s fanged, bird-eating frog and the skin-feeding Caecilian, are relatively new discoveries.  I’ve taken the liberty of extending beyond our usual subjects to include a parrot-eating bat and the well-named Goblin Shark.

Halloween Crab, Gecarcinus quadratus

Bright orange color and brilliant “eye-spots” on a round carapace lend this crab a pumpkin-like appearance.  Highly terrestrial, it lives along forest edges from Mexico to southern South America, returning to the sea only to reproduce.  Studies have shown that Halloween Crabs recycle vast quantities of dead leaves, acting as the “earthworms” of their ecosystems.

I’ve kept Halloween Crabs in zoo exhibits for years, and couldn’t resist purchasing a few at a recent reptile expo.  They make interesting terrarium subjects, and often give up their nocturnal ways to forage by day.  Please post a comment below if you would like information on their care. Read More »

Amphibian Declines – Pollution Worsens Disease and Parasite Attacks

Deformed FrogIn 1990, the IUCN’s Declining Amphibian Populations Task Force, to which I belonged, was one of the few large scale efforts addressing what is now known as the “Disappearing Amphibian Crisis”.  Today, with legions of biologists and hobbyists at work on the problem, we still do not fully understand why nearly 200 species have become extinct in the last 20 years – a rate 200x that of what might be “expected”.  But we do have some insights, one of which was highlighted in a recent journal article (Philosophical Transactions of the Royal Society (Biology) .  It appears that stress, much of which is in response to what we are doing to amphibian habitats, is worsening the effects of normal pathogens and diseases.

Parasites and Insecticides: a Confusing Scenario

As the reality of worldwide amphibian declines became apparent, herpetologists and private citizens began noticing increasing numbers of deformed and dead frogs. In 1995, school children in Minnesota made headlines when they found dozens of deformed frogs in a local pond. Since several chemicals are known to cause growth abnormalities, researchers began focusing on pollutants. At the Bronx Zoo, I worked with a veterinarian who studied African Clawed Frogs, and was amazed to see ovaries develop in males that had been exposed to Atrazine (a common insecticide). Read More »

Boa Constrictors and their Relatives – Natural History and Captive Care

Malagasy tree boaThe 53 species in the family Boidae are an amazingly diverse group of snakes that have colonized habitats ranging from rainforests to deserts, in countries as diverse as Canada and India. Among them we find treetop dwellers, aquatic species, confirmed burrowers and generalists equally at home in farmland, savannas, desert fringes and forests. I’ve had the good fortune of studying Anacondas, Rosy Boas and others in the wild, and remain fascinated by all.  Please be sure to post some thoughts about your favorites below.

Classification and Terminology

The family Boidae is divided into 3 subfamilies. Most boas are placed in the subfamily Boinae. The ten Sand Boas of southern Europe, Africa and Asia, the Calabar Ground “Python” and North America’s Rubber and Rosy Boas are classified in the subfamily Erycinae. Ungaliophiinae is comprised of the Oaxacan, Isthmian and Panamanian Dwarf Boas.

The term “boa” usually refers to the Common Boa. A short “first name” is applied to others, i.e. Rough-Scaled Boa, Rainbow Boa, Malagasy Tree Boa, Pacific Boa.  Read More »

Water Scorpion Care and Habits – Aquatic Insects for Arachnid Fans

Water Scorpion with guppyOver the past several months, I’ve spent much time collecting aquatic insects with my nephew, who is quite the intense little naturalist (please see photos – I’m having as much fun as he!).  In addition to our usual haul of backswimmers, predacious diving beetles, dragonfly larvae and the like, this season I was pleased to find a healthy population of Brown Water Scorpions (Ranatra fusca).  Combining characteristics of mantids, walking sticks and scorpions, all modified for life underwater, these amazing creatures are simple to keep and fascinating to get to know.

Aquatic Insects as Pets

In years past, I set up aquatic insect exhibits for several zoos and public aquariums, but it seems that interest remains rather low among private invertebrate keepers.  This surprises me, as their range of lifestyles rivals that of their land-bound cousins, and never fails to astonish me even after all these years.  Please see this article for information on aquatic beetle care, and watch for others in the future.

Natural History 


Water Scorpions are classified in the order Hemiptera and the family Nepidae.  Members of the order Hemiptera, known as True Bugs, have sucking, beak-like mouthparts.  Examples include cicadas, giant water bugs, backswimmers, leafhoppers and aphids. Approximately 270 Water Scorpion species have been described worldwide, 13-15 of which inhabit North America.  No doubt many others are awaiting “discovery”.

Physical Description

The body of the Brown Water Scorpion resembles that of a terrestrial stick insect and is yellowish-tan to dark brown in color.  Others, including those in the North American genus Nepa, are flattened in appearance.  The front legs are raptorial (designed for grasping) and superficially similar to those of a praying mantis.  Unlike a mantis, however, the terminal segments of the Water Scorpion’s front legs fit into a groove when not in use, and swing out like folding knives when needed.  These hook-like leg tips can be seen in the photo showing a Water Scorpion poised just below a guppy.

The middle and hind legs are about as long as the body, and paired breathing tubes are situated at the end of the abdomen.  This species reaches 1.75 inches in length (to approximately 3 inches including the breathing tube).

Water Scorpions can fly, but do so only rarely.

Amazing Organs

Three pairs of disc-shaped organs on the abdomen, known as false spiracles, enable Water Scorpions to gauge water depth and compensate for changes in water pressure.


From southern Canada through much of the continental USA to northern Mexico.


Poorly adapted for swimming, Water Scorpions favor the still waters of ponds, swamps, lake edges and canals, where they remain immobile among plants and sticks.  The photo of my nephew “waiting in ambush” shows their typical habitat.


Water Scorpion predatory hooksThis voracious carnivore feeds largely upon the body fluids of invertebrates, but will also take small tadpoles, fishes and newts.  Water Scorpions are ambush predators, relying upon camouflage when hunting.  They lash out with the front legs and subdue prey via salivary fluids injected through the sharp beak.  These fluids contain chemicals that tranquilize prey and initiate digestion; food is consumed in liquid form, in the manner of spiders.


Eggs are inserted into living or dead plants, and hatch in 2-4 weeks.  The nymphs resemble the adults (incomplete metamorphosis) and mature in 4-6 weeks.

Captive Care


The aquarium should be covered and the water slow-moving.  Water Scorpions are poorly-equipped for swimming, and will perish if buffeted by strong currents.

The tank should be well-stocked with plants (preferably live) and sticks that rise to the water’s surface.   Water Scorpions breathe by extending the abdominal breathing tubes above the water’s surface, and cannot utilize oxygen dissolved in the water. They will not thrive if unable to station themselves on a plant or stick near the water’s surface.

Filtration and Water Quality

Water Scorpions may be kept in an unfiltered bowl, jar, or aquarium if provided a weekly water change (please see photo of my simple enclosure).  Live plants will enhance the aquarium’s appearance and assist in maintaining water quality.  If filtration is desired, be sure to avoid strong water currents.  Sponge, undergravel, and corner filters are ideal.

Although Water Scorpions inhabit waters that are often subjected to varying pH and ammonia levels, water quality should not be ignored. In this regard, they should be maintained as are tropical fishes (please write in if you need further information).  Water used in the aquarium should be treated with chlorine/chloramine removal drops and maintained at pH 6.8-7.2.

Light, Heat and Water Quality

Temperatures of 65-82 F are well-tolerated.


Water Scorpions are attracted to prey by movement, and will take small crickets and bits of fish, shrimp and earthworm from tongs.  I also offer small guppies, mosquito larvae and blackworms.  I’ve not seen them take smaller prey items, but mosquito larvae do disappear (and seem not to be buzzing about the house!).

Compatible Species

In common with many aquatic insects, Water Scorpions will consume smaller individuals of their own species.  However, as captive breeding seems not to have been recorded, keeping several in a well-planted aquarium would be worthwhile (reduced temperatures and a shortened light cycle in winter may encourage reproduction).

These slow, deliberate hunters will not get enough food in aquariums housing diving beetles, water boatmen, fishes and other aggressive feeders.  In such situations, they must be individually fed via tongs.

Captive Longevity

Adults over-winter and can live for 2 – 2.5 years.


Child with Water ScorpionAs you can see from my 4-year-old nephew’s smiling face, Water Scorpions are rather “stiff” and cannot bite if held as illustrated.  The long beak seems quite formidable, but several observers report that it cannot pierce human skin (this re Brown Water Scorpions; others not mentioned).  I’m wary of aquatic insects, however, as even the smallest predatory species can usually inflict a painful bite.  After so many decades of being bitten and stung by creatures large and small, I have no desire to experiment!  I advise that you handle via tongs or a net.

What Can I Do?

Insects and other invertebrates occupy every conceivable aquatic habitat, from birdbaths to swamps and even the sea.  Running a net or small strainer through just about any bit of available water will yield a treasure trove of interesting creatures, many of which are quite easy to keep and even breed.  So get out there and look around, and please feel free to write in with suggested topics, so that I can cover your favorite species.



Further Reading

 Diving Beetle Care

Video: Australian Water Scorpion

Water Scorpion Natural History and videos

Insect Families in the Order Hemiptera

American Box Turtles as Pets – Care and Natural History

Male Eastern Box TurtleThe beautifully-patterned American Box Turtles (Terrapene spp.) are very popular among reptile enthusiasts worldwide. They are extremely responsive, intelligent, calm, and may live for 60-100 years…what more could a turtle fan want!  Unfortunately, there are many misconceptions concerning their care.  The following information will enable you to meet their needs…please post any specific questions you may have.

Note: Box Turtle populations have declined drastically. In addition to habitat loss and road-kill, many were exported to foreign pet markets when European tortoises were protected by law.  Please purchase only captive-bred animals.

Natural History

Four Box Turtle species the Eastern, Spotted, Ornate and Coahuilan – range from southern Canada through most of the USA and into Mexico.  Ten uniquely-colored subspecies, including the Florida, Gulf Coast and Yucatan Box Turtles, are also recognized.

Box Turtles frequent woodlands, marshes, fields, agricultural land, and many other habitats.  Some, such as the Eastern Box Turtle (T. carolina), are largely terrestrial, while Three-Toed Box Turtles (T. carolina triunguis) and others split their time between land and shallow water.  The Coahuilan Box Turtle (T. coahuila), the group’s only truly aquatic member, is found only in Mexico’s Cuatro Cienegas Basin.  Several of my colleagues at the Bronx Zoo studied this species in the wild, and I had the good fortune to work with a breeding group for many years; please look for my future article on this most unique turtle.

Although certain other turtles posses shell hinges that allow the plastron (lower shell) to be drawn up (“like a box”), in no group is this ability so well developed as the American Box Turtles (please see photo). Read More »

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