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Common Name: Japanese Ratsnake, Blue General, Climac
Scientific Name: Elaphe climacophora (Boie, 1826)
Japanese Name: Ao-Daishou, Nezumidori, Satomeguri & Shirohebi (used for the albino phase).
As its common name suggests this snake occurs throughout Japan, its neighbouring islands and the disputed Russian Island of Kunashiri where it inhabits various biotypes including forests, grasslands, bamboo thickets as well as urban areas. Kunashir Island forms are reported to live close to the thermal springs where the warmth of the water would help with thermoregulation.
It is an agile climber and has been found in trees up to 6 meters high, presumably in search of birds and their eggs which are part of their natural diet. Japanese Ratsnakes have a series of modified vertebrae with the 29th to 44th having a sickle-shaped recurvature with a drop-shaped bony ending. These modified vertebrae are used to break the egg as they swallow it. They hold it in an 'S' shaped loop and compress until it breaks with an audible sound. This is unlike the egg eating habits of Pantherophis obsoletus lindheimeri which dissolve the shell with gastric juices. Other egg eating ratsnakes (P. vulpina, P. quadrivittata) crush the egg to break it by straight muscular force, and the related Pine Snake will use a hard object like a rock to press against to break the shell once swallowed. Specialized egg eaters of the genus, Dasypeltis, use modified vertebrae to actually pierce the shell of the eggs. They then take the contents down into their stomach and regurgitate the shell. Japanese Ratsnakes also take rodents, frogs and lizards in their natural diet. Unlike Elaphe quadrivirgata, there are no marked diet preferences or body size differences between mainland and island specimens.
Being a semi arboreal species, this species appreciates a large enclosure with several well secured branches where it can exhibit its natural climbing abilities. A relative humidity of 60% with the addition of a humid hide and large water bowl, (both the Kunashir and striped forms especially will love to soak occasionally), will make them feel comfortable. A thermal gradient of between 25-28°C (77-82.4°F) with a hot spot of 30C (86°F) in the daytime, dropping several degrees at night can be achieved with the use of one of several heating methods, wired to a good thermostat. Several hiding places should be offered in both the warm and cooler ends which will make this shy species feel more secure.
Some individuals are docile and handleable, whilst others remain nervous and defensive, biting and musking whenever you remove them from the cage. Elaphe climacophora have two enlarged teeth (not fangs) at the back of their mouth and like Coelognathus radiatus, have the same three finger toxins and lack of an effective delivery system. I have had several bites from mine which bled longer than you would expect, stung like crazy for a few seconds and itched for a few minutes up to an hour afterwards, leaving evidence of the enlarged teeth in my hand as two small puncture holes. The bites where hard and I believe that with pressure on the gums a minute amount of venom may be released, certainly with prey capture this might be the case.
In captivity they readily take defrosted rodents at all ages, and quails eggs can be offered on an occasional basis, either on the floor of the vivarium or in a 'nest' attached to the branches.
Starting out life as a 40cm hatchling they can attain a length of 120cm by the age of two. After this the growth rate is considerably slower with the maximum length of 180cm being reached at approx 10 years of age. Sexual maturity can be reached in their third year, although only fully achieving this in their fourth year is not unusual. Male E. climacophora, unlike some other ratsnakes, undergo spermatogenesis in August. This is continued through to October and ceases in November when they are preparing for brumation. Mating takes place from May to July after a 3-4 month brumation in the dark at 8-15C. Courtship begins with the male chasing the female. In an attempt to subdue her, he may bite the back of her neck or body (copulatory bites) and hold on until he manages to align his cloacae with hers and copulation begins, whereby he releases his bite if he hasn't already done so. This is unlike the courtship behaviour of the Fox Snake, Pantherophis vulpinus, where the male will continue to bite down on the female.With the Fox Snakes, I've even witnessed the male having the female's head in his mouth. Copulatory bites are not something to worry about usually and do not result in any major injury. If you do witness it, then a topical application of betadine to clean the bite area as a precautionary measure to stop any infection taking hold might be a good idea, but usually no intervention is needed. Male combat dances have also been reported for the Japanese Ratsnake.
After a successful copulation, and a gestation period of approx. 50 days, the female will deposit her clutch of eggs 5-14 days after her prelaying slough. A typical clutch consists of between 5 and 24 eggs depending on the size and maturity of the female. Incubated at 27-28C, they typically begin hatching after 48-54 days, although longer periods of up to 74 days have been known, and also as short as 44 days. The hatchlings will slough within 10 days and readily take defrosted pinkies.
The colour of normal Japanese Ratsnakes are quite variable, ranging from dull brown through various shades of green with lighter specimens also known. This may be a reflection of where they are from, with darker specimens coming from the more northerly islands where the temperatures are somewhat cooler and the dark pigment helping to absorb more heat. They are born with a series of blotches which change ontogenetically to an effectively, striped form. The adult pattern is somewhat variable with some individuals retaining the juvenile pattern and others a mixture of the two. This may have some bearing on their scientific name, as ‘climaco’ means ladder in Latin, and 'phora' means bearing, suggesting both the stripes and blotched pattern being combined. The heads are a uniform grey colour.
Hadley & Gans (1972) describes the pattern of the blotched phase as: 2 light dorsal scale rows on either side followed medially by irregular dark lateral blotches 2 to 4 segments long and 3 to 5 rows wide.
Kunashir Is form:
Japanese Ratsnakes from the Kunashiri Island are a bright green colour with flecks of yellow and a solid turquoise coloured head. They are much sought after by hobbyists.
Elaphe climacophora of the striped phase are born a grey-brown colour with four stripes. As they mature they develop a lot of yellow and green pigmentation and in my opinion are the prettiest of all the 'natural' occurring morphs.
Hadley & Gans (1972) describes the pattern of the striped phase as:
They typically have one light dorsal scale row adjacent to the ventrals on either side. Flanked medially by a stripe of three dark dorsals, a single light dorsal, a stripe of three dark dorsals, and terminates in a mid-dorsal light stripe three scales wide.
Albino (Shirohebi):
In the City of Iwakuni, Yamaguchi Prefecture, Japan, a natural population of wild Albino Japanese ratsnakes exists. The habitat along the River Nishiki where these snakes live was declared a national monument in 1924, and the snakes themselves in 1974. Japanese people consider them as messengers of the Japanese good luck goddess, Benzai-ten. This natural population which has been recorded as early as 1738 is slowly decreasing due to urbanization of habitat areas. Possible genetic defects, including scale anomalies and asymmetric or abnormally large eyes, have been recorded and may be signs of a small gene pool and a contributory factor to their dwindling numbers. A breeding farm has been set up in 1967 by the Japan Snake Institute to breed, raise and study these snakes. Already they have had great success with resolving some of the anomalies that this population was showing. WC Albinos are strictly protected by Japanese law. Captive bred, however, have made it into the hobby; but are still very rare in collections.


Growth and Maturity of the Japanese Rat Snake, Elaphe climacophora (Reptilia, Serpentes, Colubridae).Hajime Fukada. Journal of Herpetology, Vol. 12, No. 3, pp. 269-274
Convergent Ontogenetic Change of Color Pattern in Elaphe climacophora (Colubridae: Reptilia). Wayne F. Hadley, Carl Gans. Journal of Herpetology, Vol. 6, No. 1, pp. 75-78
Seasonal changes in spermatogenesis and ultrastructure of developing spermatids in the Japanese rat snake, Elaphe climacophora. E Hondo , M Kurohmaru , M Toriba , Y Hayashi
Designer Reptiles and Amphibians By Richard D. Bartlett, Patricia Pope Bartlett
Reptile and Amphibian Variants, Colors, Patterns and Sales. H. Bernard Betchel. 1995
Ecological Diversification of Insular Terrestrial Reptiles: A Review of the Studies on the Lizard and Snakes of the Izu Islands. Masami HASEGAWA
A Monograph of the Colubrid Snakes of the Genus Elaphe FITZINGER. Klaus-Dieter Schulz. 1996

First published in the February edition of our Ratsnakes Digest.


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