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Common Name: Twin Spot Ratsnake, Bimac, Chinese Leopard Snake
Widely accepted Scientific Name: Elaphe bimaculata
Longevity: Captive Twin Spot Ratsnakes may live between 15 and 20 years

Etymology
Elaphe
Greek: elaphos - Deer
bimaculata
Latin: bi - Two
Latin: maculatus - spotted

Ventrals: 172-207
Subcaudals: 67-78
Dorsals: 23-25

 
Introduction

An attractive small species, specimens of the blotched phase (Form 3 - see below) have been compared to Zamenis situla, the European Leopard Snakes, a popular and sought after species, which is where the common name Chinese Leopard Snake originated from. Males of the Blotched phase are generally the most colourful.
 

A species that is commonly confused and looks very similar in appearance is specimens of Elaphe dione (Dione Ratsnake / Steppes Ratsnake) that originate from China. In the past hobbyists have unintentionally hybridized these two species believing that they had either a pair of E. bimaculata or E.dione, when in fact they had one of each species. In the hobby it is not unusual for this species to be mislabelled as E.dione and vice versa. There are a few differences between them that might not always be evident by a casual glance. These being:

Head Pattern:
In E. bimaculata the head pattern is V shaped with pointed ends usually very regular. Generally connects to several dorsal blotches
In E. dione it is U or W shaped usually widening on the neck. Finishing at the nape or only connects the first blotches and is always of an irregular shape

Head Shape:
In E. bimaculata it is narrow and long whereas E.dione has a broad blunt head shape.

Supralabials:
E. bimaculata: 8-10 Rarely 11
E. dione: 10-12

Dorsal Blotches:
The dorsal blotches of E. bimaculata are edged with a distinct black border whereas those of E. dione are very faint or indistinguishable.

Incubation:
When incubated at the same temperature the eggs of E. bimaculata generally hatch at 40 days whilst those of E.dione hatch at 25 days

Further differences are in the chromosome count: E. bimaculata - (2n = 34) & E. dione - (2n = 36) chromosomes
 

A Brief Taxonomic History

Twin Spot Ratsnakes belong to the family Colubridae, which resides in the subfamily Colubrinae, they further belong to the genus Elaphe, species bimaculata. There are no subspecies of Elaphe bimaculata.

First described in 1925 by SCHMIDT, this species was formerly misidentified as Elaphe dione: Elaphis dione (Gunther 1888) Coluber dione (Boulenger 1894). Even today there is some confusion between Elaphe dione from China and Elaphe bimaculata by hobbyists as the two species look very similar.

Natural History:
The full range of Elaphe bimaculata is not yet fully understood, because of confused sightings of Elaphe dione, which it closely resembles. It is reported to inhabit the Chinese provinces of: Jiangsu, Anhui, Jiangxi and Hubei. Where it can be found in the foothills and valleys between 50 and 1000m altitude. The Twin Spot Ratsnake inhabits the edge of forests, wasteland with sparse vegetation, cultivated areas, fields, gardens and can be found in he vicinity of water.
 

Photo Credits
kafka4prez, leowsean, DCT_pics, Laurence & Annie, Britrob, das farbamt ( Flickr.com)

In the wild the diet of E. bimaculata mainly consists of small rodents, they have also been reported to take lizards, birds and their eggs.

Diurnal, this species is most active in the late afternoon.

In their natural range, The Twin Spot Ratsnake occurs in three forms, with the Blotched (Form 3.) being the one mostly seen and favoured in the hobby. All three forms are kept and bred in the hobby, as well as variations, as breeders have bred the different forms together, creating differing looks.

Form 1. ( Striped )
The background colour is a yellowish brown with four dark brown stripes which begin at the neck. The striped contain dark reddy brown spots which are outlined in black. In both sexes the scales anteriorly are smooth whilst those at the rear are lightly keeled. The head is narrow.

Form 2. ( Blotched / Striped )
The background colour is mainly yellow with four dark brown stripes which start at the neck. The stripes contain reddish brown to red spots which are outlined in black. Dorsally these spots can sometimes be joined together in to dumbbell shaped markings. The black outline of the spots is not as distinct as in form 1. The scales of females are lightly keeled, whilst those of the male anteriorly are smooth whilst those at the rear are slightly keeled. This is however very variable. The head of the males is narrow whilst the females is somewhat wider.

Form 3 ( Blotched )
The background colour can be grey, yellowish brown or olive. Dorsally there are mostly dumbbell shaped markings of brown or reddish brown, these separate towards the tail and continue as narrow stripes. Black outlined spots are also present laterally. Both males and females have smooth scales, although individual scales may have some light keeling to them.The head of both sexes is narrow. This form corresponds to the descriptions given by both Schmidt (1927) and Pope (1935).

In all three forms the labial scales are yellow. In the Striped forms the ventral scales are speckled with dark spots whereas the blotched from has distinct black blotches which intensify towards the tail.
 

 
Captive Origin:

The first recorded breeding of Elaphe bimaculata that we could find is in 1985 by Klaus Dieter Schulz. Many wild caught Twin Spot Ratsnakes have entered the hobby since then and keepers have been successful in breeding them. This means there is a quiet a large diverse gene pool in the hobby.

Size:

Twin Spot Ratsnakes are sexually dimorphic with females attaining lengths of between 80-100cm although larger specimens have been recorded up to four feet (120cm). Males are smaller and not so heavily built and generally only reach approx 60-80cm. Both sexes hatch out at 9-11 inches (25-30cm) and grow quickly, it is not unusual for females to of attained 70cm in their first year and males 50cm.

Temperament:

Hatchlings can be a little defensive, which is demonstrated by flattening their head giving it an almost triangular shape, presumably imitating the head shape of a venomous species. If startled they may attempt to bite, more usually though they will vibrate their tail to deter a potential threat. Another defensive trait is the excretion of a strong smelling ruddy brown liquid (musk). Most captive bred specimens will calm down with age and become handleable, whilst others although they may not attempt to bite will still continue with musking and can be a little flighty. Not usually seen in captive bred Twin Spot Ratsnakes, but a trait witnessed in Wild Caught individuals when distressed, is balling, where they hide their head within their coils.

Diet:

Hatchlings will readily accept small pinkies as their first meal, with a feeding regime of approximately every five to seven days for the first six months with the size and quantity of food being increased as they grow. It has been noted by a few breeders that offering live pinkies to hatchlings will stress them, presumably the erratic movement of the prey upsets them.

Sub / Adults have a marked preference for Rat Pups and small prey items, often ignoring any larger prey offered to them. A feeding schedule of every seven to ten days is appropriate at this age. Gravid and post laying females should be fed more regularly. Small Quail eggs may occasionally be taken.

As a general guide when feeding snakes the meal you offer them should only just be seen in the stomach, if the scales are stretched around the stomach after you have fed a food item next time offer something smaller, like wise if you can't see that the snake has eaten then increase the size or quantity of the next meal.

Food items should be thoroughly defrosted before being offered and slightly warmed through, some keepers defrost there snakes food in a plastic bag in a bowl of warm water, changing the water when it chills this helps to warm the mouse all the way through. Others will defrost the food naturally at room temperature and then warm it through by placing it on a heat mat or localizing heat with the aid of a hair-dryer. Defrosting prey items directly in warm water is not recommended because some vitamins and minerals can be lost in this process, with them being leached into the water.

Never defrost your snake’s dinner in the microwave, at the worst it will explode and at best, the extremities will be cooked!


Sloughing:

All snakes periodically slough (shed, ecdysis) their outer layer of skin, how often mainly depends on the growth of the snake, hatchlings can slough as often as every four to six weeks but there is no set time pattern for this. Adults will shed less often maybe only 5 times a year.

At the onset of a shedding cycle your snakes’ appearance will become somewhat duller, the usual black markings may take on a more grey appearance and the overall appearance is muted. What is happening is that a milky secretion is separating the outer layer from the inner layers of skin, loosening the outer layer ready for it to be discarded. This opaque appearance will affect the eyes too and they will take on a blue appearance, you may hear other keepers say my snake is in the blue, this is what they are referring to. At this point the snakes eyesight is very poor and the skin quiet delicate, you should not handle your snake until they have finished the shedding process completely. They may become aggressive whilst in shed; this is due to their restricted eye sight and subsequent uneasiness. Food should not be offered whilst a snake is in shed as the bulge in its tummy can hamper the shedding process and the discarding skin can act as a tourniquet. Also, energy is used in the sloughing process that may otherwise have been used to digest the meal, putting further unwanted effort into the process.

The eyes will remain milky for approximately three days and then gradually clear, this is because the secretion has been absorbed into the top layer now making it pliable and easily removed. The snake will look more or less normal now but within 2-3 days it will find a suitable rough object in the vivarium to rub its snout on, breaking the skin free away from the jaw lines, it will crawl out of it’s old skin. This process may only take 5-10 minutes and many keepers miss this unique experience. The whole sloughing process from start to finish lasts approximately 10 days. Healthy snakes usually have little or no difficulty with shedding and tend to shed their skins in one entire piece. Exceptions to this include snakes with injuries and those housed in enclosures with suboptimal temperatures and/or humidity levels.


Vivarium Size:

Hatchlings:
Hatchlings can be raised in 3 litre containers heated by thermostatically controlled heat mats (these should be placed under the tank and not cover more than one half of the tank; one third of the tank is recommended). This set-up will be fine for the first few months, progressing to larger tubs as they grow. A substrate of kitchen roll or newspaper is ideal at this age, hides should be made available in the hot end and cooler end. A moss box for humidity to aid the sloughing process should be made available at all times.

Adult:
A 24 x 18 x 18" vivarium or similar sized container is suitable for an adult. It is always an exciting time, moving a snake into a vivarium, as you can now furnish it with branches, plants, rocks and a more appealing substrate. Provide plenty of hides, including a humid one.

A simple equation for determining the minimum size of a vivarium for your snake is generally Length of enclosure plus Width of enclosure should be equal or greater than the total length of snake.

Temperature and Humidity

A thermal gradient of 27C / 80F hot end, 22C / 72F cool end, is required for Elaphe bimaculata,with a relative humidity of 60-70%. A humid hide is beneficial to this species. When approaching a slough, the cage should be misted daily to increase the relative humidity which will aid the sloughing process. Adequate ventilation is also a must to stop the air inside the vivarium becoming stale and we suggest a vivarium with at least two ventilation grills, one high up and one lower down at opposite ends of the vivarium, this will allow a good air flow through the enclosure, while helping to achieve a nice thermal gradient.

 
 JanFebMarAprMayJunJulAugSepOctNovDecYear
°C 2.7 4.4 9.1 15.4 20.9 24.9 28.5 28.2 23.3 17.6 11.4 5.2 16.0
°F 36.9 39.9 48.4 59.7 69.6 76.8 83.3 82.8 73.9 63.7 52.5 41.4 60.8
Average 24hr Temperature - WUHU, Anhui Province ( Wuhu is located on the south bank of the Yangtze river )


Snakes are poikilothermic, also often referred to as ectothermic and as such, rely on an external heat source to maintain their preferred body temperature. Ectothermic means that they use external environmental conditions to control their body temperature, poikilothermic means that their internal temperatures vary while performing different bodily functions, such as shedding, feeding etc. and again this is largely achieved via external environmental conditions.

A reptile’s ability to digest food, use energy and its ability to protect itself from disease, are dependent upon reaching the correct body temperature. Snakes can change their body temperature by moving back and forth from a warmer part of the cage to a cooler part and vice versa. If snakes are kept in temperatures which are too warm or too cold, this places stress on their immune system and can lead to problems.

Substrate:

A variety of substrates can be used for sub-adult and adult Twin Spot Ratsnakes, a couple of considerations when deciding what to use should be, ease of cleaning, will it mould or become a soggy mess with daily spraying, is it soft with no sharp pieces and most importantly is it non toxic?

E. bimaculata like to burrow so any substrate used should of at least two inches, which will allow for this natural behaviour.

Suitable substrates include sphagnum peat moss, coconut coir and aspen.

Cedar shavings should never be used for any reptile as they are toxic and cause respiratory problems, acting as a skin irritant.

Vivarium Décor:

Plants, plastic being the best for ease of use, as they are easily cleaned, these will also serve as additional hiding areas.

Twin Spot Ratsnakes like to climb and rest in plant covered branches, the addition of these within their enclosure also makes an interesting part of the décor. These should be secured to the sides of the vivarium to prevent any accidents. Ideally, the branch should slope from the bottom of the enclosure to the top and end near a guarded heat source so the snake can bask.

Reptile branches can be bought from most reptile shops. If you are going to find your own branch, perhaps from your garden then be aware that some woods are toxic to snakes, willow, birch, beech and fruit trees are non-toxic and therefore safe to use. It is also important to sterilize the branch first before using it, to kill any bugs that may be lurking in the bark.

Large rocks that cannot be upturned, not only serve as an interesting addition to the cage furniture to explore but also gives the snake a solid rough object to begin the sloughing process on.

Hides: Being a shy and secretive species several hides should be placed in various areas of the cage, with one of them being a humid hide, which is beneficial for the overall well being of this species, without such a hide they may have problems sloughing. Elaphe bimaculata especially like flat hides, like cork bark and slate.

Water: Fresh water should be available at all times and presented in a sturdy water container, that isn’t easily turned over causing spillages and large enough for them to curl up and soak in if they wish.

Brumation:

Like most captive Ratsnakes that require a brumation period, this will occur in their second year. To prepare your Twin Spot Ratsnake for brumation, make sure it has had no food for three to four weeks prior to cooling, also that the temperature is normal during this time, allowing the snake to fully digest its last meal and empty its gut. It is essential that the snake is completely empty before cooling begins as any food left in the gut/intestines could produce toxins that could kill it. After this, the temperature should be lowered gradually over a few weeks until it’s at the desired temperature (50-59 F / 10-15 C). The snake should not be fed during this period but fresh drinking water should be available at all times. As long as you can maintain these lower temperatures, your snake can be left in its vivarium. A more common practice is to prepare a box with a well fitting locking lid, that is well ventilated and transfer the snake to this, moving it to somewhere where the temperature is within the range they require.

Perhaps a spare bedroom or under the stairs, somewhere where it’s easy to get to so as you can check the snake and change its water regularly, equally important is somewhere quiet and out of bright light. After 8-12 weeks the snake can gradually be warmed up over a one to two week period and can then be offered food again.


Breeding:

Twin Spot Ratsnakes can mature at an early age, males can be sexually active at 11 months of age and females at 18 months. Although it is better to wait until the female is in her third year before any breeding attempts are tried as smaller animals may have difficulty with egg laying.

Mating can occur any time of the year in the vivarium if pairs are housed together, although only one clutch of eggs per year is generally laid in the spring. Twin Spot Ratsnakes who mate in the autumn months and then brumated will go on to lay fertile clutches in the spring without any further introductions. Mating is usually a lengthy affair and can last in access of ten hours, sometimes twenty four hours or more. The gestation period for E. bimaculata is quiet long compared to other Ratsnake species and believed to be temperature related. Schulz recorded 79 days gestation for one of his females, other hobbyists have also noted a similar duration from high 60's to 80 days. Clutches of eggs typically contain between 3 and 12 eggs and measure approx 50mm in length

After brumation and the females post brumation slough, they can be introduced to one another. Males will sometimes not eat at this time being more interested in breeding than eating. Once several copulations have been witnessed or the female looks fatter in the mid body they should be separated. The female should be fed regularly, every five to seven days on appropriate size rodents, which will be smaller in size to avoid undue pressure on her developing eggs. If she refuses food in her early days of pregnancy try enticing her to eat with much smaller food items than usual, she may as her pregnancy progresses refuse food all together, this is normal. The most important thing for a gravid snake is a stress free environment.

The female should be given a laying box. A plastic container big enough for her to coil loosely in, filled with damp sphagnum moss. She should be able to feel safe in her laying box, for this reason we do not recommend a clear box, but one that is either opaque or ideally solid sided.

After her pre-laying shed she may become restless, cruising the Viv for hours on end, eventually she will settle into her laying box where she will remain until she lays her eggs. This usually happens anywhere from 5-14 days after she has shed. Care must be taken when checking the box for eggs; if she gets spooked she may hold onto the eggs and become egg bound. If she is in the process of laying when you check, just replace the lid gently and check again in several hours. Do not disturb her by taking out any eggs until she is completely finished.
 

Incubation:


It is always best to have your egg boxes ready in the incubator for when they are needed, this way the temperature of the vermiculite is right and you have had time to experiment with the right water / vermiculite ratio, usually 1.1 by weight is right for most colubrid species including the Twin Spot Ratsnake.

Female Twin Spot Ratsnake will typically lay between 3-12 eggs. These should be removed from the laying box to the incubation box preferably wearing a pair of latex gloves to stop the transfer of oils from the hand to the eggs, which could impede the oxygen/carbon dioxide transfer through the shell during incubation.

One method of incubation is to fill a plastic container two thirds full with damp vermiculite (when a handful is squeezed in the palm of the hand, it clumps together and only no water should be produced). Vermiculite is a sterile medium that can be purchased from your local garden centre. Don't unnecessarily handle the eggs and make sure the female has completely finished laying before removing them, as unduly disturbing her whilst in the process of laying can result in her stressing and holding on to the remainder of the eggs (resulting in her becoming egg bound - dystocia). The incubation box should have a fitted lid, and the humidity inside should be between 95- 100%, some condensation will form on the lid but if this is too much and is dripping on the eggs, this means the incubation medium is too wet. Wipe the lid with some kitchen towel and sprinkle a little dry vermiculite over the surface of the eggs to take up the moisture.

The eggs should be checked weekly removing the lid will give a good exchange of air, towards the end of the incubation period once every couple of days is advised. Developing eggs actually breathe they take in oxygen and release carbon dioxide. If the carbon dioxide builds up to dangerous levels, then the eggs will fail. Also for this reason, egg boxes should not be over crowded and ideally eggs should be laid in the box singularly not in a clump. Although, if the eggs have adhered to each other it is advised that no attempt is made to separate them, as damage can be caused in doing so.

The eggs can be incubated at temperatures between 78-82F (25.5-28C), expect them to hatch after 35-48 days. Typically eggs of the Twin Spot Ratsnake incubated at 82F (28C) will hatch after 40 days. Incubation time of E. bimaculata eggs is also somewhat dependant on the length of gestation in the female and is thought to be the result of temperature selection /availability of the female

Eggs that are incubated on too a wet medium may absorb more water and this subsequently can lead to lose of nutrients for the developing embryo resulting in weak hatchlings, too wet an incubation substrate can also lead to dead in egg, in the final stages of incubation the hatchling will absorb a lot of moisture from the egg, thereby letting the egg shell become more pliable for piping if the eggs have become water logged through too wet a substrate this can hinder this natural process. It is better to err on the side of caution aiming for slightly drier than too wet, as this is easier to rectify. If the eggs look dimpled then they are too dry (eggs however do dimple towards the end of incubation as they are getting ready to hatch). Do not spray eggs directly, just simply pour a little water around them, they will regain their shape within a day.

Hatchlings should always be housed separately, to prevent stress, the risk of cannibalism and for you to be able to make more accurate records of their feeding, sloughing and general health.

Quarantine:

The first and often only purpose of a quarantine is to protect your established collection from unwanted diseases and parasites that may possibly be carried by newly acquired animals. All new snakes and reptiles that you bring into your home where there are others, need to be quarantined for at least three months or the maximum time known for the incubation of diseases that affect the species you are keeping. This should be regardless of whether it is a captive bred specimen or wild caught animal. The most commonly seen parasite is the snake mite, these can be seen as tiny black crawling bugs on your snake or in the enclosure, these need to be dealt with as quickly as possible to stop the spread to other snakes in your collection and to stop them multiplying to a stage where they pose a serious risk to your snake. There are many products available from reptile stores especially for eradicating these mites, please read the instructions carefully or take advice from your vet. It is not within the scope of this guide to give advice on treatments of parasites and diseases but just to make you aware that there are some and how important the quarantine period is to monitor the health or your new snake.

Captive bred snakes however are usually disease and parasite free, but why take the risk of infecting other animals when a period of solitude away from others can prevent the spread?

During quarantine, you should not share water bowls or any other cage equipment between vivaria, including feeding tongs. Don’t handle established stock on the same day as dealing with your new snake or if you have to, deal with the established stock first then the new snake. Always shower and change your clothes after dealing with a snake in quarantine before tending to your established stock.

This really is an important step in keeping your collection healthy, disease and parasite free and we strongly suggest that you read more about it.

Morphs:

There are no known genetic colour morphs being bred in captivity at present that we are aware of. However Albino and Hypomelanistic specimens have been recorded, an Albino specimen is being/has been maintained in captivity in the USA by Glenn Polanco. This Albino Twin Spot to the best of our knowledge never produced any eggs, although in 2003 she did appear gravid, these eggs where reabsorbed. A photo of this specimen can be found HERE . Another specimen is shown on a Hong Kong website owned by Pro breeder

Special Notes:

When you first purchase your hatchling it should be left for a minimum of one month to settle into its new environment. No handling within this time to allow it to settle into a good feeding regime. Most people make the mistake of handling there new pet too soon, this can result in the snake becoming stressed and refusing to feed. For the first month the only contact should be for feeding and routine maintenance (cleaning and changing the water). After this initial settling in period regular handling of 2-3 times a week will ensure that your snake becomes manageable. Snakes should not be handled when they are in shed, nor should they for three days after being fed as this could result in them regurgitating there meal. You should always wash your hands with at least hot water and soap before and after handling any snake or reptile, although an alcohol scrub to kill germs would be better.

Record keeping is a good way of monitoring your snakes health, and events such as feeding, sloughs, weight and lengths can then be looked back on if there is ever a problem with your snake.

References

1. SCHULZ, K.-D : A Monograph of the Colubrid Snakes of the Genus Elaphe Fitzinger 1996
2. SCHULZ, K.-D.: Die hinterasiatischen Kletternattern der Gattung Elaphe, Teil 5 Elaphe bimaculata (SCHMIDT, 1925). Sauria 02/1986 Pg.23 - 26
3. SCHULZ, K.-D.: Asian Rat Snakes of the Elaphe Genus Pt.5 Elaphe bimaculata 'Snake Keeper' Vol.2 No.6 1988
3. http://forum.kingsnake.com/rat/messages/11359.html (Albino Twin Spot)
4. http://www.probreeder.com/pages/collection/elaphe_bimaculata.htm (Albino Twin Spot)


Author: Sue Knight


DISCLAIMER: This care sheet is intended for guidance only, it is a conceptual understanding of this species and their needs in captivity and the wild. Whilst the author and the Ratsnake Information have made every effort to ensure the information contained in this guide is accurate to the best of our knowledge. The Ratsnake Information & author accept no liability or responsibility arising from reliance upon the information contained within this guide, or any information accessed internally or externally to The Ratsnake Information via links included in this guide.

We strongly suggest that you use this guide as part of your research into this species and not wholly rely on the information contained herein.

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This site has information on the following genera of Ratsnakes ... Spilotes, Spalerosophis, Ptyas, Zamenis, Elaphe, Rhinechis, Senticolis, Pseudelaphe, Pantherophis, Bogertophis, Orthriophis, Gonyosoma, Oreocryptophis, Oocatochus, Euprepiophis, Coelognathus, Archelaphe