Ovophis tonkinensis - Info & care

Ovophis tonkinensis, (Bourret, 1934)

Note: we @ hetterrarium.com do not advise nor want to stimulate anyone to purchase or keep venomous snakes. There are many potential risks and there are just as much if not more non-venomous snakes that are just as satisfying to keep without the risk and responsibility towards yourself and bystanders that comes with keeping venomous snakes. It takes many years of extensive experience with many facets of the snake/reptile hobby before one is ready, if ready at all for the responsibility to properly take care and keep safe of these snakes. Remember that anyone is different. Also in their reaction to venom. So even a potential non-life threatening venomous snake can cause mayor heath issues, loss of limb, kidney functions or your life when your body reacts badly to the venom injected.

That being said. There are a small group of reptile keepers that do a great and responsible job of keeping these animals. Based on a huge amount of experience and knowledge. And it is important to HetTerrarium.com to share knowledge. As we can learn a lot from these articles. Even without feeling the specific need to keep a snake like this in our collection.

Ovophis are small sized pitvipers that range thru a large part of Asia. There is not much known about their ecology. In captivity these snakes show some very interesting behaviours. Ovophis tonkinensis is one of the species that is kept and also bred in captivity. They can be in some degree very polymorphic depending on the region they come from.

The whole genus of Ovophis is under constant discussion when it comes to the classification of species and subspecies. It is suggested on numerous occasions that Ovophis tonkinensis is a synonym to Ovophis (monticola) convictus. Or that it is another subspecies of the Ovophis monticola. Because of this we advise anyone that is looking to add these snakes to their collection to make sure there is knowledge of the origin. This does not only help when it comes to reproduction, but can also prevent anyone from potentially unintentional crossbreeding.

Status:  As these snakes live in high mountainous regions that are not easily accessible and deforestation is not as abundant as in the lowlands and they are not part of any Asian food market or medicine scheme. These snakes are not under great threat and although they are not encountered a lot because of their reclusive life the population seems stabile. They are not included in any Cites documentation nor protected in their home range.

General appearance:  All Ovophis are small but heavy bodies snakes. The head is broad and strongly divided from the neck. The tail is relatively short. Their body type can be seen as the Asian version of the Australian Acanthophis sp, or the African Bitis sp. The scales are smooth, the top of their head is a very dark till black colour. Wish is strongly divided with a light brown till yellow stripe rutting from the nose till the back of the head. The side of the head has a intricate pattern of dark and light colouration. Their eyes are very beautiful and relatively small and have the same colouration as the side of their heads. The heatsensors of these pitvipers are very close to the front of the head and as all pitvipers they have a selenoglyph dental type. The venomglands are big and can be seen as bulges on the sides of the head. The overall body colour can be a light brown, cream or even yellow till orange colour. In captivity especially animals from Hong Kong and ‘Tam Dao’ (yellow form)  are known for their great vibrant colouration. The pattern consists of a range of darkbrown saddles that can create an almost banded appearance till a more checkerboard formation. We have seen some hatchlings in captivity that showed a reduced pattern on the back making it look like they were striped. But this is probably do to the fluctuation of higher temperatures during the incubation and development of the eggs in the female. The pattern on the sides is mostly connected to the pattern on the back but can be different as in a pattern that consists out of several smaller blotches and partial bands. The tail is very distinct, it is often a light grey dark orange till reddish colour and has a distinct white line running on top of it. This tail is used for caudal luring. Ovophis tonkinensis can measure about 40-50cm for males and 50 till 80cm for females. There is a very distinct difference between males and females (sexual dimorph). Males stay a lot smaller than the females and also they are not as heavy bodied as the females. The tail of the males is longer and is broader from the cloaca. As it needs space to keep his two hemipenis. The colouration of the males is depending on the origin often more intense or bright.

General behaviour:  There is not much knowledge on the ecology of the Ovophis. They live a reclusive lifestyle and hide a lot. They prefer very humid and cool mountainous regions and microclimates in (secondary) forests and bamboo forests. Often close to water like streams and swamps. Hiding between a thick layer of leaves, under logs and fallen (bamboo) branches or between high grass in swampy regions. They are mostly active during the evening after rainfall and this is the time they are mostly encountered by people when they are sometimes seen crossing a road. As they life such a secretive life and live in hard to reach areas there are not a lot of reports on bites from these snakes. In general they do not move a lot. They are not active hunters but prefer a burrow where they can hide, waiting for a prey to pass by. It is not uncommon for them to stay in a single place for several days till weeks. In captivity these snakes can be very active during the night. Only to use the same hole to hide over and over again. This makes us to believe these snakes do not have a huge range and will stay in certain spots for an extended period of time. Depending on the availability of food and conditions.

These snakes use caudal luring to attract prey. They use their distinct tail to attract a potential prey item. They will hide their body between leaves or branches, relying on their camouflage, and place the tail close to their head. The tail will move around like a worm. Attracting the attention of a frog, small rodent or other small vertebrate. When the prey comes close enough to the tail the pitviper will strike and hold on to kill the prey with the venom injected by their teeth. In captivity this behaviour is sometimes observed, but a lot less as they would in the wild. Simply because we often feed in abundance and the animals are not in full ‘huntingmode’ yet by the time we offer them again. Although they will take any prey when they can, Caudal luring or not.

Ovophis do something very unusual. In contrary where many venomous snakes only bite. These snakes will also ‘constrict’ their prey, whilst holding on injecting their venom. The snake will grab the prey, constrict it and keep the bite until the prey dies. During this time the vibrating of the venomglands is very clearly seen. Although venomous snakes holding a firm grip on to their prey is not uncommon. Like is seen with many climbing Asian pitvipers (Cryptelytrops, Popeia, Parias etc) that feed on birds. Wrapping of the body around the prey certainly is. There are several theories about this behaviour. The first is these snakes feed on fast arboreal rodents and birds and also slippery amphibians. Holding on to these prevents them from getting away. Another theory is that Ovophis have relative short injecting teeth for a pitviper and need to hold on to the prey to firmly inject a lethal dose. We do not know of any research about the pressure the Ovophis supply while wrapping themselves around the prey. So it is not known if these snakes only hold on, or actually apply high pressure to constrict their prey. While simultaneously injecting the venom. The constricting behaviour is seen with Ovophis in captivity, especially when fed bigger life prey. Or when they have not fed for a while and have a higher foodresponse. This makes us to believe the constricting behaviour is mainly used to overpower and restrain larger preyitems. When feeding smaller (life) prey in comparison to the snakes often they only hold on. Lifting the prey from the ground like also seen with the bigger Bitis sp. This causes the prey to struggle more without finding grip to a surface. Preventing it to hold on to something and potentially get away or cause harm to the snake, and increases the blood flow and hartrate. Causing the venom to have a much faster effect. We have not seen this behaviour with hatchlings. Only with Ovophis older than 18 months. That where offered a relative big prey.

Natural range and habitat:  They are found on a altitudes between 800 till 1600meters. The Ovophis tonkinensis ranges from Guangxi, Guanngdong and Hainan in China, thru the northern till central part of Vietnam, reaching the southern parts of the Da Lat Platea. There are thoughts of them occurring the northeastern Cambodia and eastern Laos although no current data on this is found. They prefer very humid till wet cool climates. Situated along streams and swamps with lush vegetation in (secondary) forests and bamboo forests. Most of the animals that are kept in captivity originate from Tam Dao, Vietnam and Sa Pa, China

Captive requirements:  Ovophis tonkinensis that are well settled are actually not very hard to keep in good health in captivity. They seem to adjust well to a high range of temperatures (depending also on locality of origin) and ones started will feed strongly. There are several options when it comes to setups to keep these animals. We will describe her the two that have worked best for us. Keep in mind. These are venomous snakes. And venomous snakes already have a bad reputation and many think it should not be allowed at all to keep these in captivity by the general population. So a escaped snake is not acceptable. Not only can it cause a potential risk to the snake, you or worse, a bystander. A media hype about a escaped pet dog eating human killing tyrant of a snake. Is probably not the best advertising for our hobby.

As these snakes do not get to big and are relatively inactive a terrarium that measures 1x0.6x0.6 their total bodylength is a good degree of measurement when it comes to the minimal needed size of the enclosure. This would mean an enclosure that measures 60x45x45 till 90x45x45 for a single adult. (Exo terra glass terrarium standard sizes). We always advise to keep venomous snakes separate outside the breeding season. Simply because it is easier to keep your focus on one snake then on multiple. It Is also commonly known that many pitvipers, although not always apparent, can be territorial. Sometimes this is not directly seen because there are no fights. But often snakes will lay in the furthers corner away from each other. Unnoticed animals can be stressed, leading them to stop feeding and have a lower resistance. Making them more susceptible for health issues.

Hatchlings and semiadults can be raised in a plastic well ventilated box like a faunabox. Which we place in a terrarium as an extra border of security. This box can be easily setup with a substrate mix of moss and cocopeat and potential some leaves for decoration and extra hiding. We use cork hides so the animals can feel secure. Always a waterbowl big enough for the animals to bath in. Although bathing behaviour is very sparsely observed. When the Ovophis have grown and well settled they can be setup in a more naturalistic enclosure.

These snakes lend themselves well for a bio-active setup. Although a setup like this can make observation harder. Which is for security reasons needed with the maintenance of venomous snakes. A setup like this does look better, is more naturalistic for the snake and is a lot less maintenance. As a big part of the potential waste is eaten by the small invertebrates that live in the soil and humidity is kept higher because of the plants. When hides are tactically placed observing the snakes can be done. As you also want to see the snake first before opening the terrarium. If we setup a bio-active for these snakes. We start with a Exo-Terra glass terrarium. We really like these enclosures for many snakes, especially small Asian pitvipers. As they close well ,U can use a lock and all light fixtures are outside the terrarium. This prevents the snake getting wrapped around a heat source but also makes sure the terrarium does not need to be opened and the snake taken out when a light needs to be maintained. This not only reduces potential contact with a venomous snake, but also prevents you from needing to destroy your nice setup to get the snake out. A background is not needed as these snakes are terrestrial but it does look nice and plants and mosses can grow against it. Best is to make a fixed background yourself. As the Exo-terra background had slots for cables where snakes can get behind. U can use a substrate mix of mainly cocopeat mixed with cypress, bark, moss and top it off with dried leaves. For a bio-active setup a drainage layer is advisable. As small cleaners u can add springtails and other small isopods to the substrate. You can plant the enclosure with Asian fast growing plants like Scindapsus, Epipremnum, Ficus and Asplenium. With cork bark logs and plates hides can be provided. Bamboo branches can be used for further decoration.

Lighting can be done with a fluorescent tube. This is mostly for the life plants and do recreate a day/night cycle. Any additional heating is often not needed. The Ovophis tonkinensis can be kept at temperatures ranging from 22 till 26C at day and 15C or lower at night during the hotter seasons.

The humidity needs to be high. The thick layer of substrate and life plants will help to keep this level up more easy. Regular misting is needed. This is also the time when the snakes get active and also drink from the drops collected on the leaves and furniture in the terrarium. On average the humidity needs to be maintained at 70/80% during the day and may rise till 95% during the night.

Diet:  Ovophis have a slow metabolism. So keep this in mind when it comes to a feeding schedule. In the wild adults will mostly feed on small rodents. But hatchlings and young are often strictly feeding on small lizards and frogs. Which can cause a problem in captivity as we all like to feed baby mouse straight away. Sometimes over time they will start feeding on defrosted pinky mouse. Best is to offer these very warm and to make them do a little but not to abruptly frogdance along the snake. Do not touch the snake on the head while doing this. While for instance Cryptelytrops will get mad and bite, Ovophis tonkinensis babies will be scared and try to get away and hide. Witch at the end is logical, no prey will start pounding a snake on its head. Sometimes gently sliding it across the end of the body and tail will get a reaction. It is very important they hold on, if they will just bite they often won’t pick up the prey to feed. If this does not work sometimes a 1 day old alive pinky or softfurr mouse will work. Other options are rubbing/scenting the prey with a (dead) frog. In the absolute last effort force-feeding can be done. But that is after trying many other options first. Ovophis babies can go a long run without food and it is suggested in the wild many babies go into hibernation without having fed a single time. So this is also an option in captivity.

Ones feeding there is no stopping Ovophis. The food response is big and they are fast and far strikers. That will hold on tightly to their prey. Hatchlings get fed every 10 till 14 days. Semiadults and adults can be fed every 14 till 21 days. But longer pauses are possible. Make sure your female is on a good weight if you also want to breed. So you may want to feed her a bit extra just after the hibernation. For adult animals semi-adult till adult mouse, semiadult softfurrs or hamsters are a good preyoption. We would advise to feed dead (defrosted or prekilled) prey. Not only does this decrease the change of a snake getting injured and a lot of stress/pain to the mouse. It is also a saver option. In case your snake does not want to feed. And you have to get a stressed mouse out of an enclosure with a stressed venomous snake. Ovophis tonkinensis still feed at very low temperatures. After reading a document about wild observations of feeding Ovophis at 7C. We decided to offer a prey to a Ovophis tonkinensis ‘Tam Dao’ at the end of a 3 till 7C hibernation. The snake took the prey without any hesitation.

Metabolism and stool:  The metabolism of Ovophis goes slow and is very efficient. This fits the cool environment they live in and the inactive lifestyle. So make sure you do not overfeed your snake. Hibernation will be a great pause for this. Ovophis can take weeks in between defecation, sometimes longer. So do not immediately worry when they seem to have some stored in their lower body. If they drink well and have enough ground space to move around in all will be fine. Don’t forget these snakes can be found in a single spot for a long period of time. A fast metabolism would mean they needed to leave the security of their hides a lot, or soil the space they live. Not only increasing the risk of bacteria growth and health issues, but also the attraction of possible predators, attracted by the smell. In captivity observations are made that animals who reside in a single spot for a while. Will ether pass faeces while being active, stimulated by the misting, or leave to take up residence in another hide. Because they passed in the previous spot.

Hibernation:  Although it seems not to be strictly needed. Providing these snakes with a hibernation will be very beneficial to their cycle and possible propagation. They live in mountainous regions where seasonal differences are much more obvious as in parts of the lowlands. So provide these animals with a hibernation of about four months at a temperature between 5-6C. Which can either be done in a cooled room or adjusted refrigerator. When they are kept at higher temperatures during this hibernation they will keep much more active and may lose weight. To introduce the snakes to hibernation daylight length needs to be lowered from 12 till 8 hours in September. Do not feed during this period. After that the animals can be places in a plastic well ventilated container. With a thick layer of moist moss and leaves and a cork hide. Always add a small waterbowl for them to drink from. In Oktober the temperatures need to be slowly dropped till 12/10C. After this you can place them directly in the hibernation chamber.

Some people suggest that slowly increasing the temperature after the hibernation is not needed. As many snakes will not become active again until temperatures are high enough. Still we would advise to place the snakes at 12/15C after the incubation. Before providing them with the regular 20-26C again. Most will feed straight away during the 12/15C period.

Breeding and captive propagation:  Ovophis take some time to mature. Normally first breeding can be done ones the animals reach an age of 5 years or older. Males can be introduced after the hibernation when all animals have fed a few times. Most copulations are observed between March and April. Males will seek out the female and court extensively for a few days. During this period they will coil around and against the female and rub her with their tail and make small body twitches. If the female is compliant, she will raise her tail so the male can insert one of his two hemipenis. Copulation will last several hours. After this the male will leave, often hiding as far away from the female as possible. Take the male out of the enclosure when this happens. Females may take a while to fertilize the follicles in their body, so egg deposit after copulation can vary. The eggs are white and have a thick but flexible shell. It is advisable to leave the eggs with the female. She will maternally incubate the eggs. If the hide is humid enough, this won’t be a problem and females often keep feeding during this period. After laying the female will often push away any unfertilized eggs. If not you can try to remove them yourself using a long forceps. If this cannot be done without too much disturbance to the female, then leave it be. As the praise says ‘good eggs don’t go bad’ and this is often true with healthy eggs. Observations are made that mouldy bad eggs that stick to a healthy egg would not damage nor grow fungus on the healthy egg. Under normal conditions the eggs will hatch between 55 till 65 days, depending on the temperatures and when they are laid. In the incubator eggs can hatch at just 23 till 35 days at a 27/28C. But these babies are often much smaller and take longer to start feeding. Maternally incubated eggs produce much bigger and healthier babies. The babies measure between 15 till 18cm.

Females can produce several years in a row after just one breeding. As they take some time to grow and maternally incubate it is advisable to only breed them ones every 2 till 3 years.

Venom:  There are many unknowns when it comes to the type of venom these snakes have. This is because of the low amount of research and low amount of bites in their home range. The venom is at least a mix of haemorrhagins and procoagulants with a possible anticoagulants. Heamorrhagins will cause bloodvessels to leak and damage red bloodcells. Causing for instance internal bleeding and bleeding from the gums, nose, ears, anus, vagina etc. Procoagulants will make the blood to cloth. Which can cause a blood clot to cause blockage of important vains. If this this does not help the coagulants in the blood will be used up, causing more bleeding. Local symptoms are pain, redness and swelling headache, nausea, vomiting, abdominal pain, diarrhoea, dizziness, collapse or convulsions. There is one confirmed death at the result of a Ovophis bite. There is no known specific antivenom.

As we mentioned we do not want to promote the keeping of any venomous snakes. There are a lot of potential risks towards yourself and bystanders. And takes a big sense of responsibility and a sufficient base of experience. If this is available and you are experience with the husbandry of Asian pitvipers. Ovophis are great species to keep. With very beautiful traits. And a lot of interesting behaviours.