That Reptile Blog – Reptile, Amphibian and Exotic Pet Care and Information

Although only 906 of the world’s 40,024 spider species are tarantulas (Family Theraphosidae), these interesting creatures are the best known of the group and among the most sought-after of invertebrate pets. Reptile enthusiasts, myself included, seem particularly drawn to them, hence their inclusion in this blog. Today I would like to provide an overview of the group and specifics concerning some readily available species. Future articles will cover care and breeding in detail.

Please Note: Tarantulas, like all spiders, manufacture venom and are capable of delivering a painful bite. Human fatalities from bites are unknown, but their venoms are relatively unstudied, and an allergic reaction is always possible. New World species also possess urticating (irritating) hairs, which are shed when the spider is disturbed. A colleague of mine required surgery to remove hairs shed by a Mexican Red Knee Tarantula (a relatively docile species) from his eye. Do not handle tarantulas, despite what you may see others do – move the spiders, if at all, by urging them into a plastic container, and wear goggles where appropriate. Please also check the legalities of tarantula ownership – several species are protected by law; others are prohibited in some states.

Tarantulas in General
Tarantulas range in size from those that mature at 1 inch in length to behemoths with 12 inch leg spans, and may be ground-dwelling, fossorial (burrowing) or arboreal. Females of several species can reach 30 years of age (most males live but 1 or 2 years).

They are found in tropical, sub-tropical and (less commonly) temperate regions of Africa, the Middle East, southern Asia, Australia, New Zealand, the Indo-Pacific, Micronesia, Central and South America, the southern half of the USA and throughout the Caribbean. Various species are adapted to live in deserts, open forests, grasslands and rainforests. A number also thrive around people, and may be found in overgrown fields, agricultural areas, gardens and even within homes.

Although considered to be “primitive” spiders, tarantulas are quite successful as a group, and are the dominant invertebrate predators in many environments. They take any animal that can be overcome, including spiders, centipedes and other invertebrates as well as snakes, frogs, lizards, mice and other small rodents. The name “bird-eating spider” was first applied to the group in 1705 when Swiss naturalist Maria Sibylla Merian included, in a book on the insects of Suriname, a painting of a pink-toed tarantula consuming a hummingbird.

Tarantulas are distinguished from other spiders by their book lungs (unique respiratory organs), the presence of 2 claws and adhesive pads on the tips of the legs and by the fact that they use their fangs in an “up and down” as opposed to “side to side” motion.

Goliath Bird-eating Tarantula, Theraphosa blondi
This rich-brown spider is the undisputed king of the trade and, with a leg-span approaching 12 inches, of the spider world as well. Relatively unknown here until the early 1980’s (please look for my future note concerning my early experiences with them), captive born goliaths are now readily available. This animal is not, however, for the beginner – they are extremely aggressive and fairly demanding as captives.

Native to the rainforests of northeastern South America, goliath birdeaters require high humidity in captivity and a terrarium of at least 20 gallons in size. They should be provided with deep, moist substrate in which to burrow, or an artificial cave . Adults are fully capable of overcoming an adult mouse, but such is not recommended as food (dead mice are accepted). They fare well on roaches, earthworms, crickets and wild-caught insects such as grasshoppers and katydids.

Mexican Red Knee Tarantula, Brachypelma smithi
Quite different from the goliath in color, temperament and captive needs, the red knee is responsible for the advent of tarantula keeping in this country. Jet-black with bright red-orange leg joints, this spider is quite calm in temperament (but can bite and shed urticating hairs, see above) and hardy. One that I received as an adult lived for 18 years, putting its total age at over 23, and similar records are common.

The red knee hails from western Mexico, and is tolerant of quite dry conditions (recent hatchlings need a fairly moist environment, however). It does well on a sand-gravel substrate and readily accepts crickets, roaches, newly-molted super mealworms and wild-caught insects. This species is now protected by the Mexican government, but captive-born specimens are commonly available.

Pink-toed Tarantula, Avicularia avicularia
Unlike the previous 2 spiders, the pink-toed tarantula (named for its pink-tipped “toes”, or tarsi) is strictly arboreal. It is also unique in that it is encouraged, rather than displaced, by human activities. Various species range from the Caribbean south to Peru, and readily colonize homes, gardens and parks.

Pink-toed tarantulas construct a thick, silken retreat on tree trunks, roof eves and among plants (where they will often bind 2 leaves together to form sturdy walls for their homes). They prefer moderate humidity, but are fairly tolerant in that regard. Oddly for a spider, pink toed tarantulas get along fairly well in groups, with 2-3 individuals usually co-existing in a tank of 20 gallons or so in size. They should be kept in a vertically-oriented terrarium (an aquarium turned on end works well) furnished with cork bark, bamboo and other climbing surfaces. Pink toes relish moths and other wild-caught insects, but also fare well on crickets, roaches and waxworms.

Thailand Black Tarantula, Haplopelma minax
This Southeast Asian native is the first of the Old World species that we will cover. Like all, it lacks urticating hairs, but more than compensates for this with its extremely aggressive nature and willingness to bite. They are also quite fast, and should not be handled. Threatened individuals rear up on their back legs to expose the large fangs – which, highlighted against a red-colored patch and often tipped by a drop of venom, are intimidating in the extreme. I have observed several to fall right over onto their backs during the threat display – a position from which, it would seem, an enemy could not approach without being bitten (I have not tried, nor will I!).

This species requires a moist substrate into which it can burrow and, being high-strung, does best with minimal disturbance. A night-viewing bulb will enhance your ability to watch the spider go about its nightly activities. Thailand black tarantulas should be fed earthworms, roaches, crickets and wild caught insects such as moths and grasshoppers.

The photo accompanying this article shows a Thailand black tarantula in typical tarantula hunting position – poised at the burrow’s entrance, ready to pounce upon prey or retreat from an enemy. The silk that you see is used to provide stability to the burrow’s walls and most likely alerts the spider, via vibrations, of approaching animals. It is not, and this hold true for all tarantulas, used to ensnare prey.

You can access a wealth of tarantula-related resources at:
http://www.exoticfauna.com/

Growing up near the Bronx Zoo, I became fascinated by giant snakes early on, as these magnificent creatures were always featured prominently in my favorite building, the Reptile House.  So it was with great anticipation that, after some years as a reptile keeper for the zoo, I set off for Venezuela to assist in field studies of the green anaconda, arguably the world’s largest snake.

Accounts of what I observed and learned during three visits to that country’s central llanos area (seasonally flooded grasslands) would fill several books.  I would like here to just give you some facts and photos – in the future, I will highlight some of my experiences in longer articles.

Despite long-standing legends to the contrary, (and, recently, a plethora of internet photos) there is only one reasonably reliable account of a snake measuring over 30 feet in length (I’ll cover the details of this and related stories in the future).  In fact, the Bronx Zoo offered a cash reward, established, as legend has it, by Theodore Roosevelt, for a living snake in excess of 30 feet.  That reward, now withdrawn, stood uncollected for nearly 100 years (I was involved in the last attempt to collect it – please look for details in the future).

The snake you see pictured here was the largest that I and my colleagues encountered.  It measured just over 17 feet long and weighed 215 pounds.  As you can see from the close-up of my hand on its head, she (all anacondas
of this size are females) put up a quite vigorous battle when captured – indeed, one of her teeth remains imbedded in my wrist till this day as a reminder!  A number of the 500+ green anacondas that were marked during the study were in the 15 to 16 foot range.

I was fortunate to come upon quite a few anacondas in the process of feeding upon a wide array of animals, including capybara, caiman, jacanas and other birds, turtles and, most unforgettably, a deer of 60 pounds in weight.  Please look for future articles on the details of these most fascinating encounters.

The Venezuelan llanos, especially in the dry season, offers a wildlife-viewing extravaganza that is difficult to put into words.  Encounters with crab-eating foxes, freshwater dolphins, giant anteaters, armadillos, electric eels, caiman, scarlet ibis and countless other creatures large and small are all but guaranteed.  Cougars, jaguars, giant otters, tamandua, tree boas, tegus and a host of others are also a real possibility.  I am planning to write an article for people who might like it explore (and “exploration” it is, in the true sense of the word) this area – please look for it in the future.

You can learn more about the field research project I described in this article at:

Anaconda Expert Wades Barefoot in Venzuela’s Swamps

Welcome to our new blog location!

Please see here for more background information on this animal’s natural history and life cycle in the wild.

General

Despite living largely underground in the wild, captive spotted salamanders adjust well to artificial caves and shelters, where they are more easily observed.  Well-adjusted captives quickly lose their secretive, nocturnal ways, and will eagerly accept food offered by plastic feeding tongs.  If attention is paid to their needs, especially as concerns temperature (see below), these stocky, brilliantly marked salamanders make long-lived and hardy pets.

Space and Other Physical Requirements

If provided with a deep (6-12 inches) substrate, spotted salamanders will establish burrows that will be defended and used consistently.  Products such as Zoo Med Eco Earth and R-Zilla Fir/Sphagnum Moss Bedding, with a bit of top soil mixed in, work well as substrates.  The surface should be covered with living or dried sheet moss, such as R-Zilla Compressed Frog Moss.  You can spot clean this type of set-up or occasionally remove the top layer of substrate – living plants in the terrarium will aid in absorbing the salamander’s waste products.

Another useful tip in maintaining cleanliness is to establish a colony of isopods (sow bugs or pill bugs) in the terrarium.  These small crustaceans can easily be collected below rocks and leaf litter.  They are excellent salamander food and avidly consume feces, dead insects and decaying moss (a bit of fish flake food added occasionally will keep them in top shape and assure that they reproduce). 

Land snails are also excellent scavengers, and both they and isopods are fascinating creatures in their own rights.  Snails usually reproduce readily in captivity, and small specimens will be eagerly devoured by spotted salamanders.

A single adult spotted salamander requires an enclosure of approximately the size of a 10 gallon aquarium.

Spotted salamanders may also be kept in ventilated sweater boxes on sheet moss or paper towels.  Each animal should be provided an individual artificial cave or cork bark shelter.

Light, Heat and Humidity

Spotted salamanders favor cool temperatures, retreating far below-ground during the summer months.  They do best at 60-70 F, and are stressed by temperatures over 76 F.  Cool basements make ideal sites for their terrariums, especially during the summer months.  My own basement maintains an air temperature of 50-54 F in the winter, during which time the salamanders continue to feed.  The drop in temperature is good for their health, and helps to maintain normal activity patterns and to spur breeding.

Breathing largely through their skin, spotted salamanders require moist conditions – their terrarium should be misted with de-chlorinated (not distilled) water daily.  Free-living adults rarely enter water other than for breeding, but a shallow, easily-exited water bowl will be utilized by captives. 

Humidity should not be raised by covering the terrarium with plastic – salamanders require circulating air and should be housed in screen-covered enclosures.  In stagnant air conditions, temperatures rise and fungus often attacks the skin.

Spotted salamanders do not require a UVB light source.  If you keep live plants in the terrarium, be sure to use a low output UVB bulb, such as the Reptisun 2.0, as too much UVB can damage the eyes of these and other amphibians.  Check also that the bulb does not cause temperatures to spike.

If you keep your salamanders in an unlit basement, it is a good idea to provide a light cycle for them in the form of a weak room light or fluorescent tank light.  They will do fine in complete darkness, but a day/night period is preferable, especially if you plan on breeding your animals.

Check back next Monday for the conclusion of this article. The image above is referenced from the Spotted Salamander entry on Wikipedia.

Spotted salamanders produce toxic skin secretions but are none-the-less consumed by garter snakes and hog-nosed snakes. Introduced trout, bass, goldfish and other fishes prey upon the larvae and can decimate a population in a single season.

Reproduction
Adults migrate from terrestrial burrows to temporary ponds (vernal pools, swamps, ditches, sluggish streams) in the early spring. The migration is triggered by snow-melt or warm rains, with adults sometimes crossing snow to reach their breeding sites. Males arrive at the ponds 1-6 days before females. I have observed them breeding in Westchester County, NY in mid March, when the water is quite cold. Despite this, I found that food for the larvae, in the form of aquatic insects and fairy shrimp, was abundant.

Large mixed-sex groups form at the pond bottom during courtship. Males deposit a spermatophore (a sperm-filled, jelly-coated capsule) on the pond bottom. The females take this into their cloaca (reproductive opening) and fertilization occurs internally.

The eggs are laid in compact, jelly-covered masses that are attached to twigs, plants or sunken logs. Each mass contains 50-160 eggs. The sight of 20 or more large, brilliantly marked salamanders writhing together in as they vie for breeding rights is really something to see – please write in if you’d like information as to how you might observe this for yourself.

A species of green algae, Oophila amblystomatis, frequently colonizes the egg mass, apparently supplying oxygen to the embryos and utilizing the carbon dioxide that they produce. Larvae from algae-colonized egg masses hatch earlier and exhibit less mortality than do those from algae-free masses.

The adults return to their burrows after breeding. The terrestrial habitat may be 75 – 1,000 feet from the breeding pond.

The larvae hatch in 8-60 days, depending upon water temperature, and have external gills. Transformation to the adult form takes place over a period ranging from 6 weeks to 18 months. In NY, the larvae typically leave the breeding ponds by late July or August, after which the ponds usually dry up.

Miscellaneous
Adult spotted salamanders have lungs but rely largely upon cutaneous respiration (the absorption of oxygen through the skin). The skin must remain moist if this form of respiration is to be effective – they are therefore, limited to damp habitats and rarely appear above ground except after heavy rains. They and other salamanders depend upon protective tree cover, leaf litter and fallen logs to retain soil moisture, and rapidly disappear from degraded habitats.

You can read more about spotted salamander natural history and conservation at:
http://www.globalamphibians.org/
Of course, you can also order my salamander book from That Pet Place (see above) – Thanks!

In contrast to frogs, salamanders reach their greatest diversity in temperate habitats – more species are found in the eastern USA than anywhere else on earth. Today I would like to take a look at the natural history of the spotted salamander – a large, local beauty that makes both an excellent “first salamander” and a fine addition to advanced collections. Next week I’ll cover their care in captivity.

Physical Description
Varies in length from 4 ¾ to 9 ¾ inches. Stoutly built, with a black or slate- colored body marked by irregular rows of brilliant yellow (occasionally orange) spots. Larvae are usually a uniform olive or brown in color with bushy red external gills.

Range and Habitat
Eastern and central North America – from Nova Scotia and central Ontario, Canada south to Georgia and west to eastern Iowa and eastern Texas. They are absent from southern NJ and the Delmarva Peninsula. Isolated populations are still to be found within NYC, on Staten Island and in Queens and the north Bronx.

Spotted salamanders favor deciduous lowland forests and meadows near forest edges and sometimes inhabit woodland patches within suburban areas. Adults require soil into which they can burrow and the fish-less bodies of water for breeding (the larvae are relatively defenseless against fish). Certain populations breed where fishes are present, but only if dense aquatic plant cover is available.

Spotted salamanders are members of the family Ambystomatidae – the mole salamanders. True to this name, the terrestrial adults spend most of their lives below logs or underground in self-excavated burrows or in those dug by mammals such as moles, shrews and field mice. They have been found at depths of 4 feet below ground, and generally forage on the surface only on damp or rainy nights. Spotted salamanders are sensitive to soil pH and avoid acidic soil.

Status in the Wild
Common in some parts of the range and drastically declining in others due to habitat loss – the removal of trees causes the soil to dry, and results in loss of the protective leaf-litter cover needed by this species. The introduction of trout and other game fish to breeding ponds quickly causes local extinctions.

Spotted salamanders typically breed in vernal (temporary) ponds, which are often small in size and only a few inches deep (these lack fish – see above). Unfortunately, such “puddles” are rarely recognized as worthy of protection, and hence are destroyed at a greater rate than are other habitats.

They are also threatened by acid rain and road-salting, both of which change soil and breeding pond pH, killing the larvae and driving off the adults. Protected by several states but not nationally, and not listed by CITES.