Corn Snakes
Distribution and General EcoIogy
This North American
species is divided into four sub-species. The
Corn Snake (Elaphe guttata guttata)
comes from the South Eastern states of North
America. The Rosy Rat Snake (Elaphe guttata
rosacea) is only found in the lower Florida
Keys. The Great Plains Rat Snake (Elaphe
guttata emoryi) is the western central
form Similar to the Great Plains sub-species
in colour, but smaller in size, as is the recently
described Intermountain Rat Snake (Elaphe guttata
intermontana). This is the only sub-species
found west of the Rocky mountains.
Note: Many taxonomists regard both Eg.rosacea
and E.g.intermontana merely
as geographical variants and not as separate
sub-species.
Corn Snakes in general are probably the most
commonly kept species and are captive bred in
large numbers. Many colour variations and patterns
can be found, including various albino mutations.
The two most readily available forms are the
Florida Corn Snake and the Carolina (Okeetee)
Corn Snake. Amongst the genetic mutations
available are the amelanistic (red albino),
anerythristic (lacking red pigment), Snow Corn
(albino), blood red (all red), Creamsicle (amelanistic
and Great Plains cross) and Striped (available
in various colours).
Most Corn snakes attain an adult length of 130
cm, Great Plains Rat Snakes slightly longer.
Housing in Captivity
Adult Corn Snakes
may be housed in a vivarium measuring approximately
90 cmx 50 cmx 50 cm. Orchid bark chips, beech
chippings, good quality wood shavings or newspaper
may be used as a substrate. A hide box or choice
of hides is essential as these snakes are basically
nocturnal and will wish to retire during daylight.
Branches are a useful addition as Corn Snakes
like to climb. A bowl of clean water must always
be available, 5" earthenware pots being the
most suitable.
Lighting is not necessary but if used, a 40
watt tube or bulb will suffice. Any lighting
must be turned off at night, and a 14 hour daytime
regime is ideal for the summer.
The vivarium will require heating and this can
be provided by one of the many types of heater
on offer Heat pad, tube or ceramic are all used
with success. Whichever method is used, a reliable
thermostat should be installed and set at between
25° C to 30° C for the summer months.
Food and Feeding
The only food the
snakes will require is pre-killed mice and small
rats. If possible, the snakes should be fed
separately in case two snakes try to eat the
same prey item.
The amount of food offered varies between individual
snakes, but as a rough guide one or two adult
mice per snake each week will suffice. If a
female has recently laid a clutch of eggs, then
the diet can be increased. Similarly, if a male
is more interested in mating the female, he
may refuse to feed on a temporary basis. Again,
an increase in food intake may be required once
the mating period has ceased.
No vitamin/mineral supplement is required as
a rodent is a perfectly balanced food package.
Seasonal Cues
If
the breeding of Corn Snakes is to be attempted,
only healthy, good sized specimens should be
prepared for mating. Before initiating the cooling
process, snakes should be well fed and then
given a three-week fasting period to allow their
system to clear any waste products. As winter
approaches, cooling must be carried out gradually,
aiming at a final temperature of 10 deg. C to
be maintained for three months. This cooling
is not essential, but there will be better results.
During the cooling period no food is offered,
but clean water should still be available.
Courtship and Reproduction
In
the spnng the heating can be gradually raised
to the optimum and feeding can commence. If
the snakes have been separated during cooling,
they can be re-paired ready for breeding. Sloughing
of their skins after a few feeds is the best
cue for mating.
Courtship is usually a very active affair, with
the snakes gliding around the vivarium, twisting
around each other. Eventually they will mate:
the female will lift her tail to expose the
cloaca. the male will then insert a hemipene
and copulation will take place for any length
of time from ten minutes to several hours. This
process may be repeated several times. After
a successful mating, the female will become
gravid. After a couple of weeks, bulges will
appear in the rear half of her ventral surface.
She will probably stop feeding at this time.
It is a good idea to remove the male from the
vivarium. The period of time from mating to
egg laying may vary, but 40 to 45 days is a
good guide.
Eggs and Young
At
between 10 to 15 days prior to laying, the female
will undergo a pre-laying slough. This period
is always constant for each individual snake.
At this time a nest box should be placed in
the vivarium A plastic box lined with sphagnum
moss is most suitable. Prior to egg laying,
the female will spend several days coiled in
the plastic box. When the eggs are laid, they
should be removed as soon as possible and transferred
to an incubator, or somewhere with a constant
temperature of 28° C to 30° C. The number
of eggs laid is very variable; however, the
Great Plains rat snake usually lays about ten
fairly large eggs, 60 mm long by 20 mm diameter.
Corn snakes may lay up to thirty-five eggs,
although twenty is a more realistic number.
Corn snake eggs are generally much smaller,
30mm long by 18 mm diameter. Many of the eggs
will adhere to each other. Some breeders prefer
to separate them, which can be done fairly easily
if the eggs have just been laid. If there is
any doubt, the eggs should be left together.
Whilst in incubation, the eggs should be kept
at 100% humidity on a substrate of vermiculite
or peat/silver sand mixture.
During incubation the eggs will absorb water
and expand slightly. The colour should stay
constant, but sometimes they discolour. This
does not appear to have adverse effects unless
they become mouldy and shrivel. If this happens,
offending eggs should be removed. The incubation
period is an average of sixty days, but this
may vary depending on ambient temperature. When
the juveniles emerge, they can be placed in
separate containers and should accept new-born
mice after their first slough. The hatchlings
should be kept slightly damp for the first few
weeks to assist sloughing.
Juveniles soon grow and the size of prey can
be increased in size and quantity. As a rough
guide, a hatchling will accept two or three
pinkie mice per week. Sexual maturity is attained
in three years.
Conclusion
It
is advisable not to pair these snakes too early
as undersized babies will result which, if they
survive, will possibly weaken the available
gene pools.
The four sub-species of Elaphe guttata are a
very popular choice of snake and are available
in a multitude of variations. If kept properly,
they can be quite long lived, are medium sized
and have a pleasant disposition.
