By William B. Gillingham,
Great Valley Serpentarium
The mangrove snake is a vividly marked
snake with bold yellow bands on a black satin background. There is
also a melanistic population in which the yellow pigment is missing
leaving white banded morph. Mangroves are mildly venomous,
rear-fanged snakes, found throughout the Malay Peninsula, Indonesia,
and Philippines. This nocturnal and arboreal hunter is often seen
during the morning basking in the higher branches of the mangrove
trees along water ways. It grows to average lengths of six to seven
feet. There are seven know forms of mangrove snakes which are
identified by their number and size of bands that form the pattern,
color, and scale count. The above subspecies, which is most commonly
imported, occurs in the Malay Peninsula and adjacent Sumatra. The
nominate race, B. d. dendrphila, occurs on Java, B. d.
annectans is found on Kalimantan (Borneo), and B. d.
gemmicincta is confined to the Celebes Islands. Three forms also
inhabit the Philippines, B. d. multicincta of Palawan, B.
d. divergens of Luzon, and B. d. latifasciata of
Mindanao. The genus Boiga is wide spread and is composed of
more than twenty species occurring in Africa, southern Asia,
Indonesia, New Guinea, and Australia. They are commonly called the
cat-eyed snakes because of their vertical pupils similar to that of
a cat’s eye.
HUSBANDRY:
Since the mangrove snakes are arboreal, thrive in the Mangrove
swamps and edges of rainforests, I have house these animals with
this in mind. My display units vary in sizes but all are large and
tall approximately 4-6 feet tall by 3-4 feet wide and 2-3 feet deep.
For a substrate I recommend the coconut chip because it retains
moisture creating a higher humidity with out much molding. Other
types of forest, aspen or cypress mulch would also work as a
substrate. Sphagnum moss can be added to help increase the humidity.
We usually mist once a day. I use a variety of sturdy living indoor
plants to create a more natural environment. However, artificial
plants seem to thrive much longer. For their arboreal needs, I use
the decorative grape wood which is attached to the entire height of
the cage. These snake are mainly nocturnal in habit, but they are
known to bask during the day stretched out on branches fifteen feet
or more above the ground. I have used various flourescent lights and
heat tape to keep their environment warm. The cage temperature
ranges from about 80*F to 88*F (night/day) during the summer and
from about 74*F to 85*F (night/day) during the winter. All lights
are turned off during the night allowing for a seasonal temperature
fluctuation. The photo period is approximately 9-10 hours throughout
the year (8 am to about 6 pm) which is controlled by timers.
FEEDING:
Mangrove snakes feed on a wide variety of prey including birds
(chicks), snakes, lizards, frogs, and small mammals. Acclimated
snakes will often accept prekilled mice and rats from tongs. I house
the male and female together for breeding purposes only, but it is
best to fed them in separate cages or try to feed them separately
and simultaneously because of their aggressive feeding behavior and
observe them carefully to avoid any conflicts. I have disengaged one
snake from swallowing up to seven inches of the other on one
occasion. At night, their behavior and feeding response is more
aggressive along with a keener vision and striking accuracy.
BREEDING:
I have successfully bred several species of Boigas and often
the babies look totally different from the parents. In the common
mangrove snake, the babies usually look identical in coloration and
pattern to the parents. In the blue-chinned green cat-eyed snake,
Boiga cyanea, the babies are a reddish brown with a green head.
The golden lace or yellow-bellied mangrove, Boiga tanahjampeana,
the babies resemble the parents. The Sulawesi cat-eyed, Boiga d.
gemmicincta, the parents are all indigo black but the babies are
beautifully ringed with yellow and red bands on a black background.
The mangrove snakes can lay up to 2-3 clutches throughout the year.
I presume that most of the breeding takes place during the night.
Only on a few rare occasionally have I actually observed breeding
during the day. The male can be very aggressive, biting and holding
the female on the neck and head and sometimes swallowing her head.
Sometimes I wonder if the male is going to bred or eat her.
Gestation is about 45 days in which 8-12 eggs are laid. A first time
captive breeder, measuring about 53 inches, laid 10 eggs. Incubation
at 83-84*F takes about 95-104 days, much longer than most colubrids.
Neonates measure 12-14 inches at hatching. They leave the egg after
absorbing a large egg sack. Their first molt takes place about
fourteen days later. Pinki mice are then offered in their little
hide area and left over night and a second night. Some will eat the
first night, and others often eat the second day. 20-30% may feed on
rodents the first feeding. I scent pinkies with lizards or frog for
those that do not eat right away. I have also had success teasing
the neonate with a pinki. Holding the snake about an inch behind the
head, I move the pinki back and forth in front of it's mouth until
it bites the pinki. They often swallow it if it isn’t too large of a
meal. I very slowly set the snake down and let him finish his meal.
This is called "assist feeding". A very low lighted room or almost
dark room works best. Sooner or later they all become aggressive
feeders. I house the neonates individually in shoe boxes to reduce
stress and distraction. They feed best in the dark or in their hide
area probably because they are nocturnal having better night vision
and feel more concealed. They can grow very rapidly depending on
their feeding schedule. They can definitely be ready for breeding in
three years. I also recommend housing the neonates separately to
prevent them from eating each other.
VENOM POISONING:
I have not experienced a severe bit from an adult. I have been
bitten by babies and have had no noticeable reaction. I have not
found much information on the toxicity of the venom of mangrove
snakes. I do have one report from a customer whose girl friend was
bitten by a mangrove snake. The woman was reaching into a dark
closet was bitten on the forearm by an escaped mangrove snake which
was about 4' in length. It apparently was able to chew allowing
venom to penetrate the wound. Her arm swelled and doctors could not
do much to reverse the swelling. After three days the swelling
stopped and her arm returned to it's natural size without any side
affects. Some people may experience a more severe reaction if they
have an allergic reaction to the venom. Even though the mangrove
snake is not considered very dangerous to us, like all other
rear-fanged snakes, it should be treat with respect. They are
technically classified as opisthoglyphous snakes, your rear-fanged
snakes, which have 1, 2 or 3 rear maxillary teeth, depending on the
genus, that are enlarged and anteriorly grooved. The salivary
secretions drain in the area of the enlarge teeth which is a pre-digestant
and incapacitates or kills the prey. Representatives included here
are the boomslang, Dispholidus, and the twig snake,
Thelotornis, both of Africa, have been responsible for human
deaths. Other well-known rear-fanged snakes of lesser toxicity are
the long-nosed tree snake, Dryophis nasuta, lyre snake,
Trimorphodon, hognose snake, Heterodon, tree snake,
Imantodes,vine snake, Oxybelis, cat-eye, Leptodeira,
of North America, the cat-eyed snake, Telescopus, southern
Europe and Africa, montpellier snake, Malpolon, of southern
Europe, African beaked snake, Rhamphiophis, of Africa,
false water cobra, Hydrodynastes, tricolored hognose,
Lystrophis, mussuranas, Boiruna, formerly Clelia,
of South America, and the Malagasy hognose snake, Lioheterodon,
of Madagascar. These are some of the more common rear-fanged snakes
associated with the hobbyist and pet trade. You should check with
your state wildlife agency to see which rear-fanged species might be
restricted or require a special permit. The lesser toxic species are
usually not restricted.
