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Leaf Litter Invertebrates as Food for Small Insectivorous Amphibians and Reptiles – Part 2

Please see Part I of this article for further information.Last time we took a look at the amazing diversity of tiny invertebrates that inhabit leaf litter, and their importance as food for small terrarium animals such as poison frogs, dwarf leaf chameleons, and young frogs, lizards, mantids and scorpions.

Collecting Leaf Litter Invertebrates
As mentioned in Part I of this article, the springtails, ants, mites, millipedes and other creatures inhabiting a single acre of fallen leaves can add up to an astonishing 3 tons in weight! So how do we harvest all of this free food?

A technique borrowed from professional entomologists (insect scientists) works quite well. Simply place a handful of leaf litter into a funnel, suspend the funnel over a jar and position a 100 watt bulb about 6 inches above the leaves. The heat will drive the resident invertebrates down the funnel and into the jar. A damp paper towel placed at the bottom of the collecting jar will assure that the more delicate animals survive.

Using Wild-Caught Invertebrates
Remove potentially dangerous animals such as biting ants and centipedes, and dispense the rest to your poison frogs, baby anoles and other such creatures. Their reactions to this novel food will convince you of its worth – most terrarium animals become noticeably excited and feed ravenously each time they are presented with novel prey species.

Use Petri dishes if you prefer to keep your pets’ meals confined to one area. Springtails, sowbugs and others may colonize the terrarium substrate if allowed to disperse, which is also useful in some cases. You can also place small piles of leaves directly into the terrarium (after checking for dangerous species) – its great fun to watch frogs and other creatures search through them for tasty snacks.

Zoo Experiences
Others far more inventive than I came up with this technique, but I have long championed it in my articles and books…usually without much luck! Even among my zoo co-workers, my pleas fell on deaf (if amused!) ears.

So, upon touring several zoos in Japan recently I was thrilled to learn that several keepers, after reading about the topic in a book that I wrote some years back (Newts and Salamanders, which for some reason is popular in Japan), tried it out. Their results were so positive that the technique is now a regular part of the husbandry regime in several collections!

Trapping Tiny, Flying Insects
The Zoo Med Bug Napper, a very effective insect trap that I rely upon throughout the warmer months, will attract tiny gnats, moths, beetles and flies along with larger insects. These too make fine foods for your smaller pets.

Further Reading…Meadow Plankton
“Meadow plankton” is a term given to the myriads of insects and other invertebrates that can be gathered by sweeping a net through tall grass in fields and in overgrown areas along roads, farm edges, parks, etc. These creatures can also be fed to smaller reptiles, amphibians and invertebrates. Please look for my future article on this topic.

Until then, a partial species list of insects that might be encountered in a typical temperate zone meadow, along with other information, is available on the website of the Invertebrate Conservation Trust.


Newt Toxins: Personal Observations and Interesting Facts

Everyone associates the poison or “dart” frogs (Family Dendrobatidae) with skin toxins, but it is to the slow, seemingly benign newts and salamanders that we should really pay heed. In many cases their toxins are far more virulent and, unlike those of the poison frogs, they are produced internally and are not dependent upon diet for their existence (in other words, the toxins do not decline after a time in captivity, as is the case for poison frogs!).

One of Earth’s Most Toxic Creatures
Over 200 compounds, some of which are medically significant, have been isolated from newt and salamander skins. Western North America’s rough-skinned newt (Taricha granulosa) possesses what may very well be the salamander world’s most powerful secretions…a single adult packs enough to kill 25,000 mice. More than one person (usually male, drunk and involved in some sort of “initiation” or dare), has suffered fatal consequences after swallowing a rough-skinned newt.

Skin secretions entering tiny cuts have rendered researcher’s limbs numb for hours, and a scientist who rubbed his eyes after touching a “woodland salamander” (I cannot recall the species, but belonging to the red-backed/slimy salamander group) wandered about blind for nearly 3 days before being rescued.

Toxins vs. Eel
Although the California newt’s (Taricha torosa) toxins pale in comparison to those of its rough-skinned cousin, they are not to be trifled with. I kept a California newt with an American eel for 17 years. The eel, a voracious predator that would as soon latch onto my hand as anything else, never once molested its seemingly defenseless tank-mate.

Next time I’ll relate an encounter I generated as a foolish 13 year old working in a pet store, which clearly illustrates the toxicity of even the most familiar of North American newts.

Further Reading
You can read more about the natural history and toxicity of the rough-skinned newt at http://www.amphibiaweb.org/cgi/amphib_query?where-genus=Taricha&where-species=granulosa&account=amphibiaweb

California Newt Image referenced from Wikipedia Commons and originally posted by Justin Johnsen

The Northern Watersnake and its Relatives in the Wild and Captivity

Watersnakes are largely ignored by herptoculturists, and I’ve never quite understood why. Hardy, prolific, and often colorful, their utilization of two habitats makes for very interesting observations. Today I’d like to focus on the northern watersnake (Nerodia sipedon sipedon), and to mention a few others.

Background color varies through shades of pale gray to dark brown, with reddish to black cross-bands. Juveniles are brightly marked, while the colors of older animals usually darken. Stoutly built, the northern watersnake may reach 4 ½ feet in length, but averages 3 feet.This species interbreeds with its subspecies, the midland water snake, which may confuse identification at range overlaps.

The range extends from southeastern Quebec, Canada to North Carolina, Alabama and Mississippi. Related subspecies occur as far west as Colorado.

The endangered Lake Erie water snake (N. s. insularis), a subspecies of the northern, is found only along Put-In-Bay, Lake Erie.

The northern water snake frequents swamps, ponds, lakes, rivers and streams. It rarely strays far from the water’s edge, but frequently basks on logs and overhanging branches. Although preferring quiet waters, I sometimes encounter them along swiftly flowing rivers.

Status in the Wild
This snake can build up large populations in suitable habitat but, in my experience, does not adjust well to human presence (it is sometimes killed in the mistaken belief that it is venomous and reduces game fish numbers).

Several years ago I visited formerly well-populated ponds on Long Island, NY, as part of a government-sponsored survey. Despite adequate habitat and a healthy prey base, I found nearly all to be barren of snakes, and local fishermen confirmed their absence.

Watersnakes seem almost “crazed” when food is scented. Legendary reptile man Raymond Ditmars reported catching them on fishes tied to a string, a feat I repeated a half-century later with admirable results. I have also taken them in minnow traps.

Watersnakes feed upon a wide variety of frogs, tadpoles, salamanders and fishes and crayfishes.

Mating occurs in early spring. The young, 9-100 in number, are born alive after a gestation period of 2-3 months (March-July).

This snake was once common within NYC but has declined dramatically. I re-introduced it to the grounds of the Bronx Zoo in 1986, and a small breeding population is now to be found there.

Northern water snakes are harmless but aggressive when disturbed, and are often mistaken for the venomous water moccasin. The confusion is greatest in the Southeastern USA, a watersnake-lovers paradise, home to 12-15 subspecies. The massive Florida green water snake (N. floridana) reaches 6 feet in length and even holds its mouth open when threatened, in a manner reminiscent of the moccasin’s display.

Various watersnake species regularly hybridize, producing a bewildering array of forms in the species-rich southeast. Despite the passage of over 20 years, I still clearly recall a gorgeously-patterned individual that I narrowly missed capturing in south Florida. It was almost certainly a mangrove watersnake (N. clarkii compressicauda), perhaps hybridized with a Gulf salt marsh or Florida watersnake. I realize that my awe seems odd in these times of captive-bred “designer snakes”, but to encounter such a creature in the wild was quite a thrill.


Further Reading
You can learn more about the natural history of the 10 Nerodia species at http://www.jcvi.org/reptiles/search.php?submit=Search&exact%5B%5D=genus&genus=Nerodia.

Nerodia sipedon image referenced from Wikipedia and originally posted by Brian Gratwicke

Nerodia rhombifer image referenced from Wikipedia and originally posted by LA Dawson.

Green Iguanas and Raccoons in Southern Florida….an Interesting Dilemma

Released and escaped green iguanas (Iguana iguana) have now established huge populations in southern Florida. Although I must admit to a certain degree of fascination with introduced species, there can be no doubt that the massive lizards have caused a great many problems in their adopted environment.

An Impressive but Bothersome Invader
Normally arboreal, iguanas adapt to treeless environments by commandeering burrows occupied by the endangered burrowing owl (Athene cunicularia), displacing the birds and destroying eggs and chicks in the process. Ever hungry, the 4-6 foot long behemoths also assist the spread of undesirable invasive plants by eating their fruits and dispersing the seeds in their feces.

Among one of their most troublesome characteristics is a propensity to colonize airway strips and nearby areas. Green iguanas in Puerto Rico have caused runway accidents, and they are considered a collision hazard in Florida airports as well.

Raccoons in Cities and Nature Preserves
RaccoonRaccoons, although native, have also become problematical in recent years. Now well adjusted to people, they thrive everywhere…during my years as a nuisance wildlife trapper, I caught scores throughout NYC, including in some of Manhattan’s most densely-populated neighborhoods.

Raccoon populations in south Florida parklands reach 250 animals per square kilometer – 200 times the densities of those dwelling in natural habitats! In addition to serving as a reservoir for rabies and distemper, raccoons in Florida pose a serious threat to the nesting success of green, loggerhead and other marine turtles.

Please check in next week to see how a well-planned control program for both iguanas and raccoons went astray…and would up helping the iguana population to grow astronomically!

Further Reading
Iguanas make fascinating pets, but, as males may exceed 6 feet in length, they are not for the unprepared. Please read our cage guide, Green Iguanas, before you take on one of these impressive giants. Green Iguana image referenced from Morguefile.

The Cuatro Cienegas Slider (Trachemys scripta taylori) and other Unusual Relatives of the Red Eared Slider (Trachemys scripta elegans)


Note: For further information on red eared sliders in the wild and captivity, please see The Red Eared Slider in Outdoor Ponds  and Typical and Atypical Habitats of the Red Eared Slider

The red eared slider is familiar to herp enthusiasts the world over, but many of its relatives are not.  As one of the many subspecies of the common slider, the red-ear is cousin to a surprising variety of rare and poorly studied turtles.

Widely-ranging Subspecies

The red-eared slider is one of 15 described subspecies of the common slider, Trachemys scripta.  The common slider is considered to be the most variable, in terms of physical appearance, of all turtles, and has a huge natural range.  Common sliders of one variety or another may be found from southeastern Virginia to northern Florida, west to Kansas and New Mexico and south through Mexico to northern Columbia and Venezuela.

A Slider among Sea Turtles

The most “exotic” slider subspecies that I have handled are the Nicaraguan slider, Trachemys s. emolli, which was shown to me by a friend in Costa Rica, and the Meso-American slider, Trachemys s. venusta.  I encountered the Meso-American slider at Tortuguero, Costa Rica, where it nests on ocean beaches amidst green and leatherback turtles.

It is said that Meso-American sliders wash out to the sea from the mouths of nearby rivers, then make their way to the beaches to nest…but I have not heard an explanation of  how they negotiate the return trip.  In any event, I have observed them in large rivers and can attest to the fact that at least some individuals nest on ocean beaches, right along with sea turtles.

Sliders in the Desert and Box Turtles in Water

Perhaps the rarest of all slider subspecies is the Cuatro Cienegas slider, Trachemys s. taylori, found only in the Cuatro Cienegas Basin of Coahuila, Mexico.  Smack in the middle of the Chihuahuan Desert, this 500 square mile oasis is also home to another very rare and unusual turtle – Coahuilan box turtle, Terrapene coahuila.  Long isolated from related species, the 75+ animal species endemic to Cuatro Cienegas have developed a host of unusual survival strategies.  The Coahuilan box turtle, for example, is unique among all box turtles in spending most of its life in water.

I’ve worked with Coahuilan box turtles in captivity…its hard to describe how strange it is to see them bobbing about in deep water.  With their highly-domed shells, they seem completely unsuited for a watery existence, yet get along quite well.  Their future in the wild is tenuous at best, but they breed very well in captivity.

Further Reading

An interesting article on the unique reptiles and amphibians of the Cuatro Cienegas Basin is posted at http://www.desertfishes.org/cuatroc/literature/cc_symp1/4/j4.html.



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