Post by Ceratodromeus on Mar 7, 2015 4:31:06 GMT 5
Madagascar Leaf Nosed Snake - Langaha madagascariensis
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Langaha
Species: L. madagascariensis
Description: the Madagascar leaf nosed snake is a peculiar, venomous colubrid. Though it was described in the late 18th century, there has not been a tremendous amount of research done on it. It is a very thin snake with small eyes. The pupils are round, and each sex adorns a nasal appendage, the purpose of which is still unknown but perhaps is to distuingh between sexes. The coloration is typically brown with a tan underbelly. These snakes are very thin, which helps them live an arboreal lifestyle.
Dietary/ hunting habits: The Madagascar vine snake is a sit and wait forager, remaining motionless until prey comes into view. To understand the foraging habits of this peculiar snake, Kenneth Krysko simulated natural settings for captured vine snakes. Below, you can find the results of this study.
In some trials, the vine snake coiled around tye prey animal, perhaps to ensure that it would not escape.
From this valuable bit of info, we can theorize that such behaviors are common place in the wild. In fact, it has also been noted in other whipsnakes to sway subtly while coming down on prey. This, alongside their cryptic coloration, would make striking a prey item easier. These snakes appear to favor lizards as a prey item(saurophagy), with Tingle (2011) making several observations of attempted and successful predation attempts. No attempts on mammalian prey (genus must or rattus, for example) were noted and probably do not occur often, if at all. This being an arboreal species, birds would be another viable prey item.
Venom: being a vinesnake, it's not really a surprise this colubrid is venomous. Here's a report of envenomation in a healthy adult male human
The venom, in all likelihood, is only life threatening to the snakes prey, but also perhaps to young, sick, or old humans. No real documentation on the Madagascar vine snakes interactions with people in a wild situation is known, so it isn't possible to say much with a large degree of certainty.
Sexual dimorphism: These snakes were not noted to display much dimorphism in regards to size -- both sexes are noted to be of roughly the same size as adults. However, the odd nasal appendage does differ. The reason of which is not known, buy below you can see aforementioned differences
male
female
Reproduction: breeding occurs from august to September. Clutch sizes range from 8-14, and hatch as early as October. When the neonate hatch, they typically go to climb vegitation. The mean SVL for neonates of Krysko(2003) was 226mm and mass was 1.4g.
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Suborder: Serpentes
Family: Colubridae
Genus: Langaha
Species: L. madagascariensis
Description: the Madagascar leaf nosed snake is a peculiar, venomous colubrid. Though it was described in the late 18th century, there has not been a tremendous amount of research done on it. It is a very thin snake with small eyes. The pupils are round, and each sex adorns a nasal appendage, the purpose of which is still unknown but perhaps is to distuingh between sexes. The coloration is typically brown with a tan underbelly. These snakes are very thin, which helps them live an arboreal lifestyle.
Dietary/ hunting habits: The Madagascar vine snake is a sit and wait forager, remaining motionless until prey comes into view. To understand the foraging habits of this peculiar snake, Kenneth Krysko simulated natural settings for captured vine snakes. Below, you can find the results of this study.
...No other function has been proposed for its nasal extensions (Henkel & Schmidt 2000). While housing five wildcaught and nine captive-born L. madagascariensissince December 2000, I noticed interesting and consistent behaviour not yet documented for this species. Herein, I use three of these individuals to describe feeding behaviour in a captive setting
Two wild caught adult L. madagascariensis were housed together in a 110 l (760 x 305 x 455 mm) terrarium with live pothos (Epipremnum aureum), weeping figs (Ficus benjamina), and dead muscadine vines (Vitis rotundifolia). Additionally, a single captive born female, originating from a wild caught gravid female, was housed singly in the same manner as above. Enclosures were placed near windows to assist in an environmentally regulated photoperiod, and mean daytime temperature of 28 ºC and night-time temperature of 20 ºC was accomplished with a timer and two hooded lights (610 mm 20 WGE full spectrum and 60 WGE incandescent soft white bulbs).
Feeding trials.—At irregular intervals, readily available and live wild caught brown anoles, Anolis sagrei, Puerto Rican crested anoles, A. cristatellus, and tropical house geckos, Hemidactylus mabouiawere introduced into the enclosures and snake and prey behaviours were observed. I recorded data on stalking behaviour (swaying and/or hooding of snake), time to strike (t-strike; time from when stalking is observed until snake grasps prey), time to subdue (t-subdue; time from grasping until all obvious physical movement of prey ceases), grasping location (on prey), presence or absence of snake coiling around prey, and prey snout-vent length (SVL). Because not all variables were normally distributed, a Spearman Rank Order Correlation was preformed to determine relationships between prey SVL, t-strike, and t-subdue. Attest was performed to determine differences in t-subdue between trials where snakes coiled around prey verses those where they did not. All statistical analyses were conducted using SigmaStat for Windows (1995). Although only 22 feeding trials were performed for statistical analyses, these results were congruent with nearly four years of additional observations from 11 other L. madagascariensis. This species employs a sit-and-wait foraging strategy and is frequently motionless amongst vegetation until prey is introduced. Stalking took place once the snake was conscious of the potential prey. Stalking was preceded by hooding ( raising head and expanding body or flattening ribs dorso-ventrally just posterior to the head), and advancing toward prey while swaying the anterior portion of the body back and forth laterally. Langaha madagascariensis exhibited hooding in 19 (86%) of the feeding trials. Vision appears to be acute and snakes are stimulated by prey movement - even the breathing movements of the prey was sufficient to illicit an approach by the snake. Sporadic tongue flicking occurs to pick up environmental chemical cues during advancement (see Burger 1990; Greene 1997), sometimes until its tongue touches the prey. Occasionally a snake would place its nasal extension directly onto the back of the prey’s head for up to 10 sec, while pressing downward bending its flexible appendage before grasping. Thus, strikes are typically made at an extremely close distance and the prey appears to be unaware of imminent danger. T-strike lasted between 14-425 sec (mean = 154.32 ± [SE] 28.30) and prey were always grasped anterior to the pectoral girdle, behind the head, or in the neck region. Once prey was seized, it was usually pulled off its perch and left to dangle in mid-air, while being worked back into the mouth toward the snake’s rear fangs
From this valuable bit of info, we can theorize that such behaviors are common place in the wild. In fact, it has also been noted in other whipsnakes to sway subtly while coming down on prey. This, alongside their cryptic coloration, would make striking a prey item easier. These snakes appear to favor lizards as a prey item(saurophagy), with Tingle (2011) making several observations of attempted and successful predation attempts. No attempts on mammalian prey (genus must or rattus, for example) were noted and probably do not occur often, if at all. This being an arboreal species, birds would be another viable prey item.
Venom: being a vinesnake, it's not really a surprise this colubrid is venomous. Here's a report of envenomation in a healthy adult male human
A male L. madagascariensis (snout-vent length: 550 mm, tail length: 330, body mass: 43 g) bit the basal segment of the fourth digit on the left hand of a man (24 years old, 70 kg) on April 17, 2005, at 11:00 a.m. The bite occurred when he was attempting to record the morphological measurements of the snake as part of a biodiversity survey, which was being conducted in the semi humid dry deciduous forest of Montagne des Français (1). The snake firmly seized the finger and its enlarged maxillary teeth embedded into the dorsal side of the finger. To avoid harming the snake and to prevent further lacerations on the finger he did not attempt to force the snake to disengage immediately. Instead, he left the snake untouched and attempted to induce its voluntary release. However, the snake continued to grasp firmly, and repeated aggressive chewing motions some five or six times. Approximately 30 seconds after the snake had seized the finger, he suddenly felt severe sharp pain in his finger. In reaction to this sensation, approximately 1 minute after the bite, he managed to delicately disengage the snake teeth without causing further lacerations. As a result of the pain, he was not able to hold the snake with his left hand and was not able to continue taking the morphometric measurements.
The pain continued for the next 10 minutes but only slight bleeding was observed. Eleven minutes after the bite, the man began to feel local throbbing pain in addition to the persistent severe sharp pain in the finger. At this point no swelling was recognized and he cleaned the wound with antiseptic in order to prevent infection. After 30 minutes, he noticed a slight swelling on the anterior segment of the fourth digit. Severe pain began to abate an hour after the bite, but the swelling became more conspicuous. An hour and a half after the bite the swelling extended to the basal segment of the third digit of the left hand, and the basal part of the fourth digit swelled enormously. Two hours after the bite, he no longer felt sharp pain but continued to feel throbbing pain and tenderness, and he noticed that that the swelling had extended to the distal part of the hand causing it to swell enormously. In spite of the continuous local pain, he was able to have lunch as usual between 13:15 and 13:45. The swelling continued to extend, and 3 hours after the bite it covered the whole left fourth digit, distal part of the hand (both dorsal and ventral sides), and basal half of the middle and little fingers. This swelling was accompanied by intermittent severe throbbing and tenderness, especially on the fourth digit. He found it difficult to move the fingers as a result.
Five hours later, the progress of the swelling seemed to cease and he went to his tent to retire for the evening. However, he found it very difficult to sleep because of the intermittent severe throbbing and tenderness which continued throughout the night. The following morning, approximately 20 hours after the bite, only occasional slight pain on the bite site remained although swelling was still prominent. By 48 hours after the bite, slight pain occurred only when the bite mark was touched and pressed strongly. Swelling completely resolved at 12:00 p.m. on April 20. Slight pain in the finger, which was caused only by strong pressure diminished at 9:00 p.m., April 24. Signs or symptoms of general systemic effects, such as dizziness and headaches, were not recognized in this case. The patient was healthy when he was bitten, and no medical treatment was conducted.
The pain continued for the next 10 minutes but only slight bleeding was observed. Eleven minutes after the bite, the man began to feel local throbbing pain in addition to the persistent severe sharp pain in the finger. At this point no swelling was recognized and he cleaned the wound with antiseptic in order to prevent infection. After 30 minutes, he noticed a slight swelling on the anterior segment of the fourth digit. Severe pain began to abate an hour after the bite, but the swelling became more conspicuous. An hour and a half after the bite the swelling extended to the basal segment of the third digit of the left hand, and the basal part of the fourth digit swelled enormously. Two hours after the bite, he no longer felt sharp pain but continued to feel throbbing pain and tenderness, and he noticed that that the swelling had extended to the distal part of the hand causing it to swell enormously. In spite of the continuous local pain, he was able to have lunch as usual between 13:15 and 13:45. The swelling continued to extend, and 3 hours after the bite it covered the whole left fourth digit, distal part of the hand (both dorsal and ventral sides), and basal half of the middle and little fingers. This swelling was accompanied by intermittent severe throbbing and tenderness, especially on the fourth digit. He found it difficult to move the fingers as a result.
Five hours later, the progress of the swelling seemed to cease and he went to his tent to retire for the evening. However, he found it very difficult to sleep because of the intermittent severe throbbing and tenderness which continued throughout the night. The following morning, approximately 20 hours after the bite, only occasional slight pain on the bite site remained although swelling was still prominent. By 48 hours after the bite, slight pain occurred only when the bite mark was touched and pressed strongly. Swelling completely resolved at 12:00 p.m. on April 20. Slight pain in the finger, which was caused only by strong pressure diminished at 9:00 p.m., April 24. Signs or symptoms of general systemic effects, such as dizziness and headaches, were not recognized in this case. The patient was healthy when he was bitten, and no medical treatment was conducted.
Sexual dimorphism: These snakes were not noted to display much dimorphism in regards to size -- both sexes are noted to be of roughly the same size as adults. However, the odd nasal appendage does differ. The reason of which is not known, buy below you can see aforementioned differences
male
female
Reproduction: breeding occurs from august to September. Clutch sizes range from 8-14, and hatch as early as October. When the neonate hatch, they typically go to climb vegitation. The mean SVL for neonates of Krysko(2003) was 226mm and mass was 1.4g.