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Monthly Archives: May 2009

Salamanders Used as Fishing Bait Linked to Amphibian Disease Epidemics – Part 1

Hello, Frank Indiviglio here.  Shocking as it may be to anyone with even a passing awareness of conservation issues, tiger salamander larvae (Ambystoma tigrinum) are still widely used as fishing bait throughout much of the USA.  Run through with hooks while alive, the 6-10 inch amphibians are wildly popular with anglers seeking bass, pickerel and other fishes. 

Disease and the Bait Trade

Recently (April, 2009), biologists at the National Science Foundation announced that a significant percentage of larvae in the bait trade have tested positive for the deadly Chytrid fungus Batrachochytrium dendrobatidis.  This fungus has decimated amphibian populations on nearly every continent, and is responsible for the extinctions of local populations and, most likely, entire species. 

Herpetologists are working feverishly to control its spread, but are as yet unable to understand why the fungus has become such a devastating problem in recent years.  Often, the only hope for amphibians in its path is captivity   – colleagues of mine recently collected an entire population of Panamanian golden frogs, but the long-term outlook is quite dim. 

Virulent ranaviruses, which quickly kill many amphibians, have also been identified in larvae sold in bait shops in Arizona, Colorado and New Mexico.

Hybridization

As if the all this were not enough, the release of bait trade salamanders has resulted in the hybridization of critically endangered California tiger salamander populations (released barred tiger salamanders mated with the California subspecies). 

Hybridization threatens survival by altering critical components of the genome.  For example, when various subspecies of ibex (mountain goats) were released together in Spain, the resulting hybrids gave birth during the winter, and the population became extinct.

Getting Involved

Partners for Reptile and Amphibian Conservation http://www.parcplace.org/, an organization of professional herpetologists and interested citizens, supports numerous research programs.  Please be in contact to learn more about this issue and their many interesting volunteer opportunities.

Next time I’ll discuss other threats to tiger salamanders, their conservation status, and problems regarding food market bullfrogs.  Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

Further Reading

Please see my book Newts and Salamanders  for information on the natural history and captive care of tiger salamanders and their relatives.

Image referenced from morguefile.

 

 

Feeding Aquatic Turtles…the Problem of Water Clarity and Quality

Many aquatic turtles make wonderful pets, but nearly all share one troublesome trait – they are messy feeders, and keeping their water clear is often a major challenge.  Today I’d like to present a simple, time-saving feeding technique and review some helpful products such as undergravel filters and gravel washers.

Separate Feeding Containers

In both zoo collections and with my own aquatic pets, I have found removing the turtles from their aquarium for feeding to be the most effective way of maintaining water quality.  Nearly all turtles adjust readily to this, and feed without difficulty in plastic tubs or other easily-cleaned containers.  I’ve had difficulties only with a few retiring species, such as mata mata turtles (Chelus fimbriatus) and giant soft-shelled turtles (Pelochelys bibroni).  For these, extra space and cover in the form of floating plants did the trick.

Leave the turtles in their feeding container for 20 minutes or so after they finish eating, unless such is stressful for them (turtles are very perceptive…some are uncomfortable in strange surroundings and will try to escape after feeding).  Elimination is swift, and many pass stored wastes shortly after eating.

Partial Water Changes

In terms of water clarity and ammonia management, partial water changes are as important for turtles as for aquarium fishes.  Soft-shelled and Fly River turtles (Carettochelys insculpta) are particularly sensitive to poor water quality, but it is a concern for all species.

When doing a water change, use a gravel washer to pull water from the very bottom of the aquarium.  This is a good idea even if you keep your turtles in a bare bottomed tank, and essential if you use gravel as a substrate.

I’ve found it very useful to siphon water from the aquarium into the feeding container at meal times – this assures frequent water changes and has allowed me to keep even quite large snapping turtle (Chelydra serpentina) and giant musk turtle (Staurotypus triporcatus) aquariums crystal clear.

A Caution

One important point: do not start a siphon by drawing on its end with your mouth to fill the tube, as aquarium water should never be ingested.  Lee’s Self-starting Gravel Cleaner  is the best model to use with turtles.  If you choose a sink-compatible gravel cleaner, be sure to drain the waste water out a door or into a basement sink, and not to one used for food preparation. 

Undergravel Filters

An undergravel filter will turn your entire filter bed into a living filtration unit.  Gravel washing and partial water changes are still necessary, but if powered by a suitably strong aquarium pump, an undergravel filter will go a long way in easing tank maintenance.  I use them either alone or in conjunction with canister or other mechanical filters, depending upon the circumstances.

Food Selection

For those times when you must feed your turtles within their aquarium, choosing a suitably-sized food item will assure that less of it winds up floating about and clouding the water.  Please check out our pelleted turtle foods  for some ideas as to the sizes that are available.

Further Reading

Large species such as snapping turtles and alligator snapping turtles are interesting, but pose serious husbandry difficulties for most hobbyists.  For some ideas and tips, please see my article The Captive Care of Snapping Turtles and Alligator Snapping Turtles.

Please write in with your questions and comments.  Thanks…until next time, good luck and enjoy, Frank Indiviglio.

The Natural History and Captive Care of the Red-Tailed Ratsnake (Red-Tailed Racer), Gonyosoma oxycephalum, and Jansen’s Ratsnake (Sulawesi Ratsnake, Black-Tailed Ratsnake) – G. jansenii – Part 2

Hello, Frank Indiviglio here.

Please see Part I of this article for further information.

Handling and Enrichment

Red-tailed ratsnakes are best suited as exhibit animals.  Most do not hesitate to bite when approached, and fight vigorously when restrained.  Some may become moderately tame, but such individuals must be watched closely and not allowed in the vicinity if one’s face or near children (or, obviously, your parakeet!).

Naturalistic terrariums suit red-tailed ratsnakes well, but it can be difficult to remove them from among vines and branches.  A tall cage that allows you to clean while the snakes remain safely overhead will go a long way in reducing stress on both the snakes and yourself (not to mention wear and tear on your skin!).

They are very alert – “scenting” the cage with novel odors – i.e. a snake or lizard shed, or an egg – will keep the snakes occupied and provide a peek into their foraging behaviors (in zoo circles, this long-known practice is now termed “enrichment” and is currently very much in vogue).

Breeding

Red-tailed ratsnakes under my care and housed together in pairs have bred throughout the year without being subjected to a variation in temperature or humidity levels.  Others have bred after being subjected to a 3 month period at 70 F, during which time they had access to a basking site of 76 F.  Given their wide distribution in the wild, I suspect that these snakes are quite adaptable in this regard, or that populations vary in their breeding biology.

Most females that I have kept produced 2-3 clutches per year, with one female laying 3-4 times each year for a period of 8 years or so.  Gravid females seek secluded, moist sites in which to lay their eggs; damp sphagnum moss within a cave,  flower pot, or cork bark retreat is ideal.  Some individuals seem to prefer elevated nest sites; perhaps in the wild eggs are sometimes deposited in tree hollows and similar situations.

Please see “Reproduction” in Part I of this article for further details.

Jansen’s or Sulawesi Black-Tailed Ratsnake

The red-tailed ratsnake’s closest relative, and, per recent taxonomic changes, the only other member of the genus Oxycephala, is the Jansen’s ratsnake, also known as the Sulawesi black-tailed ratsnake, G. jansenii. 

Limited in distribution to Sulawesi, Indonesia and some small nearby islands, this gorgeous snake is variably colored in black-flecked olive or tan, and sports a black tail.  Those on Sulawesi are heavier-bodied than typical red-tailed ratsnakes, and are said to spend a good deal of time on the ground. Specimens from Salayar, an island south of Sulawesi in the Flores Sea, are pure black and quite striking in appearance.  Thinner in build than their relatives on Sulawesi, they are, like red-tailed ratsnakes, highly arboreal.

Although not widely available at this point, Jansen’s ratsnakes are prized by collectors and will likely become established in the trade in time. 

Further Reading

An interesting review of the 55 snake species that inhabit Sulawesi is posted at http://www.seh-herpetology.org/files/bonnensis/035_DeLang.pdf.

The range of the Taiwan beauty snake overlaps with that of this species, and their husbandry needs are similar.  Please see my article The Natural History and Captive Care of the Taiwan Beauty Snake  for further information.

Please write in with your comments and questions.  Thanks, until next time, Frank Indiviglio.

Image referenced from Wikipedia.

Reptile Gardens – Growing Food Plants and Attracting Insects for Your Pets – Part 2

Please see Part I of this article for information regarding specific types of reptiles and the growing of native plants.

Nearly all fruits and berries, and many flowers and grasses, can be put to good use in feeding tortoises, herbivorous lizards, and certain aquatic turtles.  Try also adding grass clumps and leafy branches to your insectivorous pets’ terrariums…frogs, day geckos and others will enjoy poking through them in search of tasty insects.

Fruit Trees and Bushes

Apple and Crab Apple

Figs

Apricots

Pears

Peaches

Most berries, including natives such as elderberry and juniper

Flowers

Dogwood

Magnolia

Dandelion

Gardenia

Nasturtium

Petunia

Petunia

Begonia

Bougainvillea

Seeds, Grains and Grasses

Thistle

Canary Grass

Maize/Corn

Sunflower

Seeds of most native grasses (“weeds”)

Pond Plants

A small pond, or even an unfiltered, water-filled container set out in a sunny location, will support duckweed, Anachris and other hearty aquatic plants, many of which are important natural foods for aquatic turtles.  Keep a few minnows in the pond to consume mosquito larvae.

You can also easily (almost too easily!) grow water hyacinth and water lettuce – both look great in terrariums housing frogs, newts and small turtles.  They require very bright light, but you can always rotate individual plants back out to the pond, where they will perk up very quickly.

Next time I’ll highlight some interesting insect visitors that you can expect in your reptile garden. 

Further Reading

Fruit and other trees attract cicadas…a mixed blessing for “real gardeners” but a bonanza for herp enthusiasts.  For my take on using these chunky summer songsters as reptile food, please see Cicadas, an End of Summer Treat

Please write in with your questions and comments.  Thanks, until next time, Frank Indiviglio.

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

Hello, Frank Indiviglio here.

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! Thanks, until next time, Frank Indiviglio.

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.

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