THE DIONE RATSNAKE (ELAPHE DIONE, PALLAS, 1773): KEEPING AND BREEDING IN CAPTIVITY; A PERSONAL EXPERIENCE

 

Gidi & Wim van de Belt.

E-mail: wimvandebelt@yahoo.com

 

Introduction

We started keeping snakes in 1995. Three years later, we wanted to start keeping some less usual snakes than our Pantherophis guttatus. We chose Elaphe dione which turned out to be interesting animals with a nice pattern. They have a really gentle disposition, are rather small and – and this is something really special – their eggs already hatch after three to four weeks. Moreover they are relatively easy to keep. Nevertheless they are rare in captivity these days. This is rather strange, especially because a snake like Elaphe anomala (Elaphe schrenckii anomala, the Russian ratsnake) is kept quite often. The reason for this remains unclear. From 2001 on, we started with the composition of several breeding groups. It was clear to us that Elaphe dione was virtually unknown. Therefore, it was an interesting challenge.

 

 

Short description

Elaphe dione is a rather small Elaphe species. The male reaches about 75 cm, whereas females can reach a length of 120 cm. Elaphe dione from China are generally larger. Dr. Rainer Fesser (Leutschach, Austria) has a female from Xian which is 170 cm in length. The distribution area is huge: from the European part of the Russian federation, up to Korea. They adjust themselves very well to different habitats, varying from steppe to very wet areas. Because of this flexibility, they can also occupy regions of an altitude up to 3500 meters.

Consequently, Elaphe dione is the Elaphe species with the largest distribution range.

 

 

Behaviour

Generally Elaphe dione is rather quiet, diurnal, curious and interested in its surroundings. However, this does not apply to all varieties. The southernmost Elaphe dione, especially Elaphe dione China, but also Elaphe dione Korea are more restless and ‘speedy’. They hide more often than the other varieties. When Elaphe dione feel threathened, they tremble with the tip of their tail. Depending on the substrate this ‘showing off’can generate some noise. This has been observed in a lot of other Colubrids. They usually are terrestrial, but our Elaphe dione China climb as well. They then mostly lie on the ‘upper floor’ of their enclosure.

 

It is remarkable that, when several snakes are housed together, some individuals tend to isolate themselves. This especially applies to somewhat weaker snakes, but can be observed as well between males and females. When the sexratio is uneven (eg. 3-1), the female lies separately from the males.

 

 

Enclosure

We started out with some hand built enclosures. Two important arguments of keeping the adult couples in cages with a glass front is (i) that we want to have good visual access and (ii) that we want the snakes to have enough space to grow. The cage is furnished with a substrate of wood shavings, a water dish in which they can lie when it gets too hot (over 27°C) and, of course, ample hiding places. They prefer inverted flower pots for hiding, rather than a low hiding place immediately above the ground.

At this point, we own more than 50 Elaphe dione, and we are building a rack containing 20 plastic boxes. The reason for us wanting to use several smaller enclosures is that we want to be able to monitor the feeding patterns of our animals very closely; the rack of 20 boxes is necessary for controlled and selective breeding, to minimize maintenance and to optimize hygiene.

 

At our facility, summer temperatures mount to 21-25°C during the day, dropping to 17°C at night time. The hibernation temperatures, which are maintained from November to February, are 8-12°C. The southern varieties are kept at a somewhat higher winter temperature of 10-15°C.

 

 

Food

In the wild, Elaphe dione eats about everything: shrews, mice, moles, birds and their eggs, frogs, lizards, snakes and insects. They prefer the smaller prey items. Feeding them in captivity is generally rather simple. We only feed them frozen thawed mice. Elaphe dione does not really constrict. Sometimes they tend to curl around their prey a bit, but mostly they press it against the substrate.

 

After hibernation, they eat a lot. This is especially true for the pregnant females, which sometimes accept an adult mouse per day. There are differences between the eating behaviour of the respective varieties. The southern varieties must ‘attack’ the prey item from their hiding spot, while Elaphe dione Nigrita only accepts warm prey. Individual differences can be observed as well.

 

A while ago, we started supplementing with vitamins and minerals. In the Tula Exotarium, we saw that Elaphe dione shows faster growth when fed with live prey. We want to examine whether the supplements can compensate for the loss of vitamins in the frozen prey items.

 

 

Varieties

At this point there are no official subspecies. It is quite possible however, that Elaphe dione Chersky and Elaphe dione China will be recognized as subspecies in the future. As Elaphe dione has such a vast range, different varieties according to locality can be differentiated.

In our collection we have:

o Elaphe dione Altai

o Elaphe dione Caucasus

o Elaphe dione Chersky

o Elaphe dione China

o Elaphe dione Korea

o Elaphe dione Tenebrosa

 

Moreover, different colour and/ or pattern varieties exist*:

o Elaphe dione Chinese Sun

o Elaphe dione Red (Red Blotched)

o Elaphe dione Super-red Striped

o Elaphe dione Orange

o Elaphe dione Lemon

o Elaphe dione Nigrita

o Elaphe dione Striped (deze kent ook een natuurlijke variant)

o Elaphe dione Tiger

 

As we only have a modest number of Elaphe dione, we do not want to claim that the facts mentioned below hold true for the entire group or locality. The description below is only given to clarify the differences.

 

-    The most common colour of Elaphe dione is grey with some dark, sometimes reddish brown spots which tend to fuse into saddles or stripes.

-         The melanistic variety ‘Nigrita’ has been known for quite some time. The Nigrita has been seen near the city of Mozdok, in the north of the Kaukasus. This Elaphe dione looks a lot like Zamenis persicus (the former Elaphe persica). Unfortunately, captive individuals of this nice variety are only kept at 4 places. Most captives are males and suffer from digestive problems. It is possible that certain genetic abnormalities are circulating in the population. Further research is necessary to elucidate this. For the Nigrita variety: also see Ryabov (2001).

-         Elaphe dione from South-Korea is somewhat lighter in colour than the North-Korean and the Russian variety. Elaphe dione from South-Korea is distributed to the south up to the island of Cheju. Elaphe dione from North-Korea tends to a somewhat greenish colour in the spots or saddles, while the southern animals display more reddish brown saddles and colours.

-         Elaphe dione from China has a yellow, sometimes very bright background colour with spots or saddles which tend to a dark reddish brown.

-         The skin of Elaphe dione Tenebrosa has a nacreous effect, with spots that are hardly visible. Young animals start of as pretty regular individuals with a basic pattern. The adults are dark (greyish black) with very small speckled dots. They lack almost any kind of pattern. The appearance of young animals only changes in their third year. When all spots vanish, snakes are designated ‘patternless’. Otherwise you have a ‘blotched Tenebrosa’.

-         The belly of Elaphe dione Chersky has a deep shining, sometimes holographic effect. Sometimes two lines or rows of blocks can be differentiated. As far as we know, Elaphe dione Chersky is not kept in captivity in Western Europe.

-         The term Elaphe dione ‘Orange’ comprises the entire snake. In a real pretty Orange, the belly is orange as well. At this moment, Elaphe dione Orange is only kept in captivity in three collections. The first meeting with an unrelated Elaphe dione Chersky at our facility took place on the 7th of may 2005.

-         Elaphe dione Tiger has a reddish brown background colour. The ‘Orange’ originated from this variety. Elaphe dione Tiger is only kept in the Tula Exotarium and at our facility.

 

 

Breeding

We mainly want to breed locality specific Elaphe dione. Unfortunately, this is not the case with most breeding efforts. The disadvantage of non-specific breeding is the creation of a ‘general’ Elaphe dione. Of course it can be quite hard to see where a particular snake originated. On the other hand, this makes things very interesting. Whenever their origin is unclear to us, we call them Elaphe dione Normal. Most of the animals in the Netherlands are Normal or Elaphe dione China. As far as we know, only a few bloodlines of Elaphe dione are present in Western Europe. For example: most of the Elaphe dione China in the Netherlands originated from two couples. This bloodline gets weaker and weaker. It is not unusual for an Elaphe dione to die from an undefined cause, but this happens more often in the bloodline mentioned above. Our goal is the establishment of several, healthy populations. Fortunately we now have some unrelated Elaphe dione breeding groups. In 2003 and 2004 we had offspring from an unrelated pair of Elaphe dione Chersky and in 2005 we succeeded with Elaphe dione Altai.

 

Apart from the locality specific breeding projects, we want to collaborate with Ivan Arinin (Tula, Russian Federation) to investigate other possibilities. For example: the Chersky complex gave rise to the Tiger and Orange*. However, it is not our goal to breed an array of colour varieties as in Pantherophis guttatus and Python regius.

 

Breeding Elaphe dione is rather simple. The southern varieties mostly attain sexual maturity after two years, whereas the northern form needs three years. We especially consider the size and body condition of the female and prefer breeding them after their third year.

 

It is important not to hibernate males and females in the same enclosure. Immediately after rising the temperature, they have to be put together for mating. If we do not observe a mating after one week, the male is removed and we retry a week later. However, several methods are possible. Some of our couples are housed together throughout the year, with good results. The matings then can be seen all year round, unlike what is mentioned in the literature. But for specific breeding efforts, separate housing is advised.

 

There are several suitable points in time for putting the males and females together. Obviously, the first moment is directly following hibernation. But also autumn, immediately before cooling them down, is suited. In addition, it seems that females are willing to breed immediately after the post-oviposition shed. It is noteworthy that males refuse food when they are in the breeding season. This is also true when there are only males in the cage.

 

Mating takes place when all is quiet and lasts for a long time. Mostly from 18-24 hours, but we also observed a copulation of Elaphe dione China which lasted for 36 hours. We believe that this is one of the longest lasting matings in snakes. The time span between copulation and oviposition is about 2-2,5 months. The females usually shed a last time about one month before oviposition. The number of eggs varies from three to 18. However, the average is five to nine. The incubation period is remarkably short for an Elaphe species: from 18 (Striped) to 36 days (China).

 

The temperature of the incubator is 26-27°C during the day and 22-24°C at night time. As temperatures tend to fluctuate in their natural habitats as well, a non-constant incubation temperature seems important to us. It is possible that the incubation temperature influences the sexratio. We are now trying to investigate this, in cooperation with the Exotarium in Tula. It is possible to keep the temperature of the incubator at 22-23°C. The incubation time then lasts a little longer, but the resulting offspring is much more robust.

 

Elaphe dione can store sperm. Thus it is possible to obtain fertile eggs following hibernation, when a mating took place in autumn. Sometimes two clutches are deposited in one season. In 2004, we obtained offspring from Elaphe dione Chersky in may (2-5) and October (2-3). Klaus D. Schulz also mentions this phenomenon in his Monograph of Colubrid snakes of the genus Elaphe Fitzinger. Offspring hatching in autumn are markedly bigger and can hibernate immediately. However, we feed them before winter.

 

Once the eggs are laid, the shell reacts with the air. Immediately after oviposition, the shell is soft and flexible. After a few hours, the egg gets whiter and harder. Sometimes a so-called ‘window’ occurs’. In such a case you can look through the shell and see the vessels within. This is caused by a lack of calcium. It slowly disappears and can not be noticed any more after a few days. In the course of time, the egg gets harder and harder, until a few days before hatching. Then it gets soft again, because of the foetus absorbing the yolk. Sometimes, the egg even slightly collapses. The young snake eventually slits the shell and pokes its head out. After about 20 hours, it leaves the egg completely.

 

 

Post scriptum,

With this article, we hope to have drawn attention to Elaphe dione. The articles by Ivan Arinin (Tula, russia) in this issue and by Jan-Cor Jacobs in Litteratura Serpentium 25-1 also prove that it is a very interesting snake.

 

 

* Also see the article by Ivan Arinin in this issue

 

 

Acknowledgements:

-         Ivan Arinin (Tula, Russia): herpetologist and Elaphe dione specialist at the Tula Regional Exotarium. He advises and helps us on a regular basis.

-         Sergei Ryabov (Tula, Russia): the manager of the Tula Exotarium. He gave his agreement for scientific cooperation, which made it possible for us to acquire special forms of Elaphe dione.

-         Timo Paasikunnas (Helsinki, Finland): head of the department Africasia in the Helsinki Zoo, for providing Elaphe dione of a 100% certain locality.

-         Klaus Dieter Schulz, for the information in his book ‘Monograph of Colubrid snakes of the genus Elaphe Fitzinger’.

-         Freek Gillissen: he pointed this snake species out to us. We bought our first couple of Elaphe dione from him.

 

 

Literature

Ryabov, S., ‘Perzische rattenslang Elaphe persica (Werner, 1913): biologie, het houden en de voortplanting in gevangenschap’. In: Litteratura Serpentium 21 (2001), 137-142.

Top

Back