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

Since their arrival in the US in the early 1980’s, White’s treefrogs (Litoria caerulea) have become one of the most popularly kept of all frogs.  Although longevities of 25 years are known, captive breeding remains surprisingly uncommon.  The white-lipped treefrog (Litoria infrafrenata), a large, attractive relative, is also infrequently bred by hobbyists.  Considering how little we know about amphibian reproduction, and the precarious state of many species, I suggest that interested frog-keepers hone their breeding skills on the relatively robust White’s treefrog.

Distinguishing the Sexes

White’s treefrogs reach sexual maturity by age 2.  Mature males are smaller than females, have loose, slightly dark skin about their throats and, when in breeding condition, sport thickened nuptial pads (used to grasp females during amplexus) on their thumbs.  Only the males call.

The Dormancy Period

A cooling off period, preferably in late winter, is critical to breeding success. Cease feeding the frogs 7-10 days prior to the cooling period and place them into an aquarium furnished with a substrate of moist sphagnum moss and cork bark shelters.

Gradually reduce the temperature to 65 F during the night (a basement is ideal) and 68 F during the day (use a small incandescent bulb to raise the temperature) and maintain this schedule for 4 weeks.  Thereafter, hold the temperature at 65 F round-the-clock for an additional 2 weeks.  The terrarium should be kept in the dark throughout this time, and the frogs should not be fed.

Preparing the Frogs for Breeding

After the 6 week “winter”, warm the frogs to 80 F over a 2 week period, and feed them heavily for 3-4 weeks.  Novel prey animals, such as wild-caught or canned insects, should be offered at this time.

Thereafter, move the frogs into an aquarium filled with 4 inches water and provisioned with live floating plants (i.e. water hyacinth, water lettuce, pothos) and basking platforms.  Use an aquarium heater  to warm the water to 82-85F, and add a florescent bulb to encourage plant and algae growth.  I recommend the Reptisun 2.0  bulb, as its UVB output is ideal for amphibians and plants…avoid strong reptile UVB bulbs.

Using a small submersible water pump, create artificial rain by pumping water into a perforated plastic container or PVC tube placed on the terrarium’s screen cover.  Allow the “rain” to fall for 6-8 hours nightly, beginning at dusk.  This step is vital in inducing spawning, and will usually result in reproduction within a week or so.

The Eggs

If all goes well, you will one morning find yourself in possession of thousands of eggs.  It is wise to plan ahead and arrange for friends or nature centers to take some of the eggs, as crowded conditions can cause the loss of the entire clutch.  Remove the adults and install an air pump driven sponge filter that provides mild water circulation.

In contrast to what is commonly recommended for some other frogs, I suggest raising White’s treefrog tadpoles in plant and algae filled aquariums as opposed to bare, sterile containers.  I have even added green pond water to several tanks with good results.

 

 

 

Further Reading

You can read about White’s treefrog breeding in the wild, and hear recordings of the males’ calls, at http://magneticisland.s4space.com.au/L.caerulea.html.

Lengthening days and warmer temperatures are beginning to register on amphibian pets nationwide, stirring long-dormant breeding urges.  Last week I was please to find that a 2 year old female axolotl (Ambystoma mexicanum) which I paired with an older male had produced eggs for the first time.  A week or so earlier a reader informed me of another spontaneous axolotl breeding.

Mexican axolotls are an ideal choice for the prospective amphibian breeder, and are becoming ever more popular each year.  With spring upon us, I thought I might pass along some photos of my pair and their eggs, along with a few tips.

The Aquarium and Filter

The eggs pictured here are set up in a PLA House Plastic Cage equipped with a Small World Filter.  PLA House Cages are available in 6 sizes, and their light weight allows for easy water changes.  I have found them indispensible in my collection, and always have a number on hand.

The Small World Filter is ideal for use with amphibian larvae, as the water return is directed upwards and so does hamper weak swimmers.  Sponge filters work equally well.  I use an air pump that provides just enough aeration to keep the eggs slightly in motion.

Providing Cover
Axolotl eggs are typically attached to plants or other structures, as seen in the accompanying photo.  Once they begin to hatch, I’ll add additional plants, nearly filling the tank so as to separate the larvae a bit and reduce cannibalism.  Plastic plants set in bases are very useful, as they provide shelter throughout the water column. The Cypress Mat  provides excellent cover on the bottom of the aquarium, where the larvae will be spending most of their time.

Feeding Axolotl Larvae
Finely chopped live blackworms form the basis of my diet for newly hatched larvae…a worm feeder lessens the likelihood of the worms clumping together (larvae often choke while trying to swallow large balls of worms).  A brine shrimp hatchery is also useful, and larvae can sometimes be induced to accept freeze dried daphnia and other invertebrates as well.

Further Reading
Pleased see my article Breeding Mexican Axolotls  for additional breeding recommendations.

 

 

Breeding season aggression is a potentially serious concern for owners of male green iguanas.  Spurred by reproductive hormones, mature males, even those which have been placid for years, may suddenly become dangerously aggressive.  This most often, although not necessarily, occurs in the late winter to early spring in the USA, so I thought that a word of caution might be in order at this time.

The Results of an Iguana Bite

If you are caught off-guard, an iguana attack can be quite severe.  A former coworker of mine, well-seasoned in reptile care, was surprised by an aggressive male who had been living without incident in the collection for over 10 years. The animal latched onto his throat and then fell to the floor, leaving a wound that required 18 stitches to close.

Timing and Indications of Sexual Maturity

Depending upon dietary and other factors, male green iguanas may reach sexually maturity as early as 18 months of age or as late as 7 years or more.  Unfortunately, the onset of aggression may be quite sudden, may not occur every year, and can last from 2 weeks to several months.  As you can see from the preceding story, animals may be even-tempered for many years before suddenly changing their behavior.

Males in breeding condition may exhibit a deepening of coloration in the orange-tinted areas of the head and body, and may head-bob and erect their crests.  Waxy secretions are usually present along the femoral pores, and dried semen is often found in their cages.  However, these changes do not always precede aggressive behaviors, so caution is always a necessity around large males.

Dealing With an Aggressive Iguana

A number of strategies for dealing with aggressive male iguanas have been proposed, with results varying widely.  I suggest that a plastic garbage can lid be held as a ready shield when working around aggressive males…a broom works well if the animal is at large in a room.  Fighting back with these tools may convince the animal to seek an easier target.  Avoiding close contact with the animal until the “mania” has passed, and keeping a shield at hand, are the safest options.  An alcohol-soaked rag (please see below) and, if possible, a helper, are very useful as well.

Some pet owners deflect aggression by providing their iguana with a towel to attack (or mate with!), while others keep the animal in a darkened room for 3-4 days to lessen the production of testosterone and other hormones.  Surgically neutering the animal is also an option, but the results of such have been mixed – in a significant number of cases the aggressive behavior remains largely unchanged.

If You Are Bitten

If you are bitten, do not pull your hand away.  Stabilize the animal so that it cannot thrash about and apply an alcohol-soaked rag to the lizard’s nostrils (avoid the eyes).  Liquor is fine to use (for the rag, not for drinking while working with your pet!) and should always be within reach during the breeding season.  Once the iguana releases its grip, secure it in its enclosure and call your doctor for instructions as to wound care.  Please do not neglect this step, as a tetanus shot or other care may be required, even for relatively minor wounds.

The Tail as a Weapon

The iguana that I am holding in the accompanying photo caused the cuts visible on my arm with a mere flick of his tail…the jaws are capable of doing much worse.  I came across him and the larger male (who, at 5’11” long, was the largest I encountered in the field) while working on anaconda research in Venezuela’s central llanos country.

Gravid Female Iguanas

Mature female iguanas often develop eggs as spring arrives.  Such will occur with or without the presence of a male, so be sure to watch even those animals which are housed alone.  Ideally, unmated females will resorb the eggs into their bodies, and have no need for nesting sites.  However, sometimes the eggs develop fully and, consequently, must be deposited.

Gravid (egg-bearing) female iguanas will usually cease feeding, or feed less vigorously, and will become very restless.  They often injure themselves by rubbing along cage walls and screening at this time, and they may attempt to dig through the cage floor.

Providing a Nest Site and Avoiding Egg Retention

Females without access to an appropriate nest site may retain their eggs, which will lead to potentially fatal health problems.  Provide gravid females with a large plastic container filled to a depth of 18-24 inches with moist top soil and moss.  Covering the container and warming the earth’s surface with a lamp may induce her to accept it as a nest site.  There are a number of other tricks you can try…please write in it you need further information.

Veterinary intervention may be required if the female refuses to lay her eggs.  In many cases, an injection of oxytosin is effective in causing the eggs to be expelled.

Further Reading

I’ve written about my experiences with wild green iguanas in another article on this blog.  Please see The Green Iguana on the Venezuelan Llanos.

An interesting article on iguana farming and conservation efforts in Belize is posted at http://www.thewildones.org/Belize/iguana.html.

 

Please see Part I and II of this article for information on scorpion natural history and further details on emperor scorpion care.

The captive reproduction of emperor scorpions is a most interesting endeavor (for hobbyists and, I imagine, the scorpions themselves!).  When properly housed and cared for, emperor scorpions are relatively easy to breed.  This is surprising, given that they are such unique and highly specialized creatures, and is an opportunity that should not be missed.  Many prominent invertebrate specialists started out with this species…keeping them is a wonderful way of becoming involved in invertebrate husbandry, and will almost certainly “hook” you for good.

Distinguishing the Sexes

In captivity, as within certain parts of the natural range, mating may occur during any month.  Adult females are longer and stouter than males, but this is not a reliable means of distinguishing the sexes.

There are some slight differences in the shape of the genital openings.  View the scorpions from below, in a clear plastic box, when attempting to sex in this manner – do not restrain them via hand or tongs.  Photos of the undersides of male and female emperor scorpions are posted at http://www.pandinusimperator.nl/EN/biology_EN.htm.

Courtship and Mating

Reproduction is most likely to occur if your scorpions are housed in a large terrarium that provides ample burrowing opportunities.  All species studied thus far perform a “mating dance”, with the pair locking claws and moving about.  It is theorized that this helps to clear a patch of ground for the deposition of the males’ sperm packet.  I imagine, but have not been able to determine for sure, that the specific dance “moves” also aid in species’ recognition among these nearly blind creatures (this is the case in “dancing” scorpion relatives, such as jumping spiders).

The male deposits a sperm packet on the ground and pulls the female over it (it is tempting here to draw analogies to salamander reproduction).  Hooks along the edges of the sperm packet latch onto the female’s genital opening, and the eggs are then fertilized internally.

Gestation and Birth

Gestation is highly variable, ranging from 7-10 months on average but sometimes exceeding 1 year.  It is likely that stress, temperature and other factors play a role in determining the length of the gestation period.

Females continue to feed while gravid, and may swell noticeably…when viewed from above, the carapace segments appear widely spaced, and seem ready to split apart (heavily-fed scorpions of either sex, however, may also appear gravid).

The young (sometimes called “scorplings”), 8-30 in number, are born alive and measure about 5/8 of an inch in length.  They are white in color and remain on the female’s back until their first moult, at which time they darken and begin to venture off on their own.  Once this occurs, they will readily accept ½ inch crickets, small waxworms, newly molted mealworms, wild-caught insects and canned silkworms.

Maternal Care of the Young

Female emperor scorpions feed their young with finely-shredded insects – this really is something to see.  By all means, try to do so by viewing yours at night with the aid of an incandescent “nocturnal” bulb.  The degree of care they provide to their young is extraordinary, and is far greater than one might expect from such supposedly “primitive” creatures.  Even among those scorpions that exhibit social behavior, emperors stand out as being very advanced in this regard.

Caring for the Mother and Her Brood

Once the female has given birth, all other scorpions should be removed from the terrarium, as she will become highly aggressive and defensive.  Do not relocate the mother…this inevitably stresses her and may cause her to consume her young.

Females with young react aggressively to any disturbance, even occasionally grabbing and eating scorplings that become dislodged from their backs.  This is not an uncommon occurrence – do not remove the remaining young unless she begins eating them regularly, as the overall survival rate is improved when clutches are reared with their mother.  I have raised several clutches to adulthood with the mother present – the key lies in disturbing her as little as possible and in providing a deep, secure burrow.

I usually raise the terrarium’s temperature to 85-90 F when rearing young emperor scorpions – this may not be essential, but I have found it to work well.

Sexual maturity in the wild is reportedly reached in 4-7 years, but captives may breed when only 12-14 months of age.  Emperor scorpions under my care have reproduced at age 3 and 4 years.

The Woodland Park Zoo provides interesting information on emperor and other scorpions in nature and captivity at:

http://www.zoo.org/factsheets/scorpion/scorpion.html

Breeding Leopard Geckos (Eublepharis macularius) at Home: Determining the Sex of Your Pets

 

The ever popular leopard gecko is a good choice as an introduction to the breeding of lizards in captivity. Success, while not assured, is common…yet, these little fellows are so captivating that even zoos and well-experienced breeders continue to work with them.

Spring’s Effect
Leopard geckos are often brought into breeding readiness by the slight changes in temperature and day length that are evident even indoors. With the imminent arrival of spring (writing from southern NY I am happy to report hearing a song sparrow singing for the first time today!), I thought it a good time to discuss how female from male leopard geckos differ in appearance.

The Pores
Take a look at your pet’s vent, which is an opening, used for copulation and defecation, at the base of the lizard’s tail. Directly above the vent, between the rear legs, you will see a series of “V” shaped little bumps, which are known as pre-anal pores. These are large and readily visible in males and tiny and less-evident in females. The pores produce waxy secretions that are used by males to mark territories and, possibly, to attract females.

Hemipenes
Between the vent and the base of the tail, mature male geckos exhibit a pair of bulges. These bulges conceal the hemipenes, which are used during copulation to achieve internal fertilization. Male lizards and snakes have 2 hemipenes, and can use either, but only one at a time, when mating.

Practice!
You may need to look at a number of geckos, or reliable photographs, before being able to reliably distinguish males from females…but once you get the right “search image” the process becomes quite easy. Please remember that only mature animals – males of age 1 year or more, females generally of age 18 months or so – will exhibit noticeable sexual dimorphism (differences in appearance).

Further Reading
Please check out the book I’ve written on leopard gecko care and natural history at http://www.thatpetplace.com/pet/prod/240453/product.web.