Although banded sea kraits are venomous they are extremely reluctant to bite humans even when provoked. They have been known to enter human residences and boats and some bites due to Laticauda colubrina have been documented. However, these attacks are extremely rare and there have been no recorded human fatalities due to this species.
Negative Impacts: injures humans (bites or stings, venomous )
Although not much has been reported regarding specific predators of Laticauda colubrina, known predators for many sea kraits include sea eagles (Haliastur indus and Haliaetus leucogaster) and sharks, especially tiger sharks (Galeocerda cuvieri). Also, more unusual predators have been observed, including the attack and feeding of a portunid crab on one Laticauda colubrina. Anti-predator adaptations have been documented in g. Laticauda. For one, sea kraits seek cover in crevices or amidst plants on land to digest their food after foraging. This is because their swimming ability is drastically impaired after a meal, leaving them vulnerable to sharks. Also, the banded sea krait, like many other species of sea krait, are highly venomous. It uses this characteristic in a remarkably innovative anti-predator adaptation in which the tail of the krait is rotated so that it resembles a second head. As noted above, the physical description of the head and tail of the banded sea krait is very similar. In this way the sea krait can trick a predator into thinking it has two dangerous, venomous heads and therefore serve as a preventive, mimetic adaptation. This is especially important because they spend much time probing crevices for food, leaving them exposed to attack from behind. Using this type of mimetic defense the banded sea krait can hunt without being overly vulnerable to predators.
Known Predators:
Anti-predator Adaptations: mimic
Banded sea kraits are also called yellow-lipped sea kraits because of a characteristic yellow upper lip. Their heads are mostly black with a yellow band extending along the lip, underneath each eye. They also have a yellow snout and a yellow band above the eye. Similarly, their tails have a U-shaped yellow marking along the edge that borders a broad black band. They have a smooth, scaled body with a blue or gray base color. Twenty to sixty-five black bands form rings around the body. Their ventral surface is typically yellow or a cream color. There is apparent sexual dimorphism in the species most likely due to differences between male and female feeding patterns. Females feed on a larger species of eel that lives in deeper water while the males feed on smaller eels that inhabit shallow water. Therefore, females, weighing about 1800 g and measuring 150 cm in length on average, are typically larger than males which are only 600 grams on average and 75 to 100 cm in length. One giant sea krait has been reported at 3.6 m.
Also, their amphibious nature contributes to their morphological characteristics. For example, they lay eggs and digest food on land and have terrestrial adaptations similar to other terrestrial snakes such as a cylindrical body shape and ventral scales for crawling and climbing on land. However, they hunt and catch prey in the ocean and have certain aquatic adaptations for life in the water including valvular nostrils, salt glands, and a laterally compressed, paddle-like tail similar to true sea snakes. Because of the geographic distribution of the sea kraits, groups from different islands may vary in some physical characteristics such as head shape and size.
Average mass: 600 to 1800 g.
Range length: 75 to 360 cm.
Average length: 125 cm.
Other Physical Features: heterothermic ; venomous
Sexual Dimorphism: sexes alike; female larger
The lifespan and longevity of banded sea kraits in the wild is unknown. However, it has been suggested that sea snakes generally exhibit a relatively high rate of mortality especially in their young. It is unknown if this trend is upheld in this species. In captivity, sea snakes have proven to be difficult to maintain and often refuse food, become anorexic, and die in a short time due to variety of known and unknown causes. In at least one case study, some of the known causes of death in captive Laticauda colubrina were sepsis secondary to a necrotizing enteritis or pneumonia, multi-organ granulomas and sepsis, and multicentric lymphoid neoplasia with secondary sepsis. These are some problems that cause limited lifespan for the banded sea krait in captivity and, because of this, the species is rarely kept in institutions in the United States.
Banded sea kraits are found most frequently in warm, tropical climates in oceanic, coastal waters. Many are found off the shore of small islands and they often hide in small crevices or under rocks. Their primary habitat is shallow coral reef waters where their primary food source (eel) resides. They have many special adaptations for diving including a saccular lung allowing them to dive to depths up to 60 m in search of food. They spend a much of their lives in the ocean but also spend anywhere between twenty-five and fifty percent of their life on rocky islets in order to court, mate, lay eggs, digest food, and shed their skins. They can also be found in mangrove areas. They have the ability to climb trees and have even been recorded at the highest points of the islands in which they reside (36 to 40 m high). They are not characterized as a pelagic species.
Range elevation: 36 to 40 (high) m.
Range depth: 60 (low) m.
Average depth: <20 m.
Habitat Regions: tropical ; saltwater or marine
Aquatic Biomes: reef ; coastal
Other Habitat Features: intertidal or littoral
Laticauda colubrina, also known as banded sea kraits, originated in the region of northern Papua New Guinea. This species of sea krait is the most widely distributed of the Laticauda complex which includes the related species, Laticauda colubrina and Laticauda saintgirosi. The breeding range of banded sea kraits is limited to the Australian and Oriental Oceanic geographic ranges. Because they inhabit coral reefs and live mostly off the coast of small islands, they have a patchy geographic distribution, a characteristic off most sea snake species. Generally, they are widespread through Indo-Australian Archipelago, the Bay of Bengal, Thailand, Malaysia, and Singapore. More specifically, the breeding range extends westward to the the Andaman and Nicobor Islands and northward to Taiwan and the Miyako and Yaeyaema island groups in the southwestern part of the Ryukyu Archipelago in southern Japan. They are present off the coast of Thailand but only on its western coast. Their eastern limit is Palua and they are present on the island groups from the Solomon Islands to Tonga in the southwestern Pacific. Their distribution is heavily reliant on several key factors including the presence of coral reefs, sea currents, suitable terrestrial shelter, and paleography. They are not found in the Atlantic and Caribbean oceanic regions.
Biogeographic Regions: oriental (Native ); australian (Native )
Banded sea kraits are considered feeding specialists. Regardless of geographic location, they have a diet consisting almost entirely of eels of the order Anguilliform and families Congridae, Muraenidae, and Ophichthidae. Females and males typically differ in their food habits leading to the sexual dimorphism in the species. Females are typically larger and eat larger conger eels. Males usually feed on the smaller moray eels.
Sea kraits use their elongate bodies and small heads to probe cracks, crevices, and small openings in the coral matrix in order to forage for eels. They have venomous fangs and their venom contains powerful neurotoxins that affect the muscles of the diaphragm of its prey. Upon injection, these neurotoxins act rapidly, drastically impairing the swimming and breathing capabilities of an eel and making it easy to subdue. After a meal, the swimming ability of the banded sea krait is impaired and it must immediately return to land to digest its prey or else be vulnerable to predators in the water.
Although often described as strictly eel-eaters, examples of other types of bony fish of the families Synodontidae and Pomacentridae have been recorded from the stomachs of some Laticauda colubrina.
Animal Foods: fish
Primary Diet: carnivore (Piscivore )
Banded sea kraits are known hosts to endoparasitic chigger mites of the family Trombiculidae. Studies have found that larger, older snakes in Singapore contain larger numbers of mites with the maximum number of mites found in one snake being 60. These mites were found strictly within the trachea. However, the chiggers have also been found in the lung sacs in Laticauda colubrina of Taiwan. There are also known to be subject to nematodes, trematodes, and cestodes.
Also, as banded sea kraits strictly prey on eels, they certainly play a role in controlling eel population in the coral reef ecosystems they inhabit. While they feed on eels, they may also be vital to the survival of one species of eel, banded snake eels (Myrichthys colubrinus). This eel species in the Indo-Pacific looks very similar to the banded sea krait and appears to mimic its behavior. Therefore, the eel may use this as a defense strategy, appearing as a dangerous and venomous animal to predators.
Commensal/Parasitic Species:
Although the economic importance specific to banded sea kraits is not referenced, it has been noted that Laticauda sea kraits have a variety of uses. For example, the skins of a variety of Laticauda have been used for leathercraft and sold in the Phillipines since 1930. The Japanese increased the demand for sea kraits when they began commercially importing them from the Philippines and exporting them to Europe as "Japanese sea snake leather". In the Ryukyu Islands of Japan and some other Asian countries the eggs and meat of sea kraits including species of Laticauda are consumed as food. Also, the venom of many snakes may have biomedical applications both in treatment and research. They are also an important part of various coral reef ecosystem and therefore play a role in the ecotourism of some of the islands and countries in which they are located.
Positive Impacts: food ; body parts are source of valuable material; ecotourism ; source of medicine or drug ; research and education
When banded sea kraits hatch from the eggs they resemble small adults. They do not undergo any metamorphosis. They display determinant growth with rapid growth in young sea kraits which gradually ceases shortly after sexual maturity is reached. Males reach sexual maturity at about one and a half years and females are sexually mature at one and a half to two and a half years. However, not much has been studied on the specific topic of development in banded sea kraits.
Laticauda colubrina is not listed on any of the databases of endangered species indicating that the conservation status of the species has not been documented and is unknown. However, because many Laticauda species aggregate on land they are highly vulnerable to capture. Commercial harvesting, human-induced reduction of habitat in mangrove swamps, industrial pollution of coral reefs and other coastal areas, and overfishing are all environmental hazards that negatively affect the biodiversity and population size of many species of sea snakes. Some researchers have proposed that rainfall and the availability of freshwater may be determining factors in many populations of sea snake species including Laticauda colubrina. To maintain a proper water balance, they drink fresh water or very dilute brackish water in order to counteract the dehydration they experience on land and in salt water. Therefore, the population dynamics of some species of Laticauda may be affected by drought and global climate change.
CITES: no special status
IUCN Red List of Threatened Species: least concern
Banded sea kraits have eyes and nostrils and can locate and identify prey by smell. In general, sea kraits and true sea snakes have well-developed eyes and Jacobson's organs but lack the heat-sensing organs found in some terrestrial snakes. Also, one study researching the reproductive behavior highlighted the vomeronasal system as a critical part of communication between males and females during reproductive processes. Contact pheromones provide the most critical cues for courtship. Males follow the trail of a female in order to court the female. Also, tongue-flicking was noticed and may be a visual communication cue. The lipid composition in the skin of conspecific males and females differs between sexes and potentially provides another cue for species and sex recognition.
Communication Channels: visual ; tactile ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; chemical
In banded sea kraits, internal fertilization is accomplished by reproductive organs called "hemipenes". Males have two of these reproductive organs and, although both are fully functional, only one is used in any given mating. They are sheathed and lie at the base of the tail. During mating, one of the hemipenes protrudes from its sheath and turns inside out. In this conformation, its surface is covered with spikes and hooks that help secure in the cloaca of the female while mating.
Three main phases of banded sea krait courtship and reproduction have been described. The first phase is called the tactile phase. Males may swim around the shore attempting to find the point of exit of a female that has gone to land. This phase demonstrates the reliance of the sea kraits on pheromonal cues in order to locate and follow the trail of a female. The second phase includes mounting and body alignment. In this stage, a male will drape itself over a female and often twitch spasmodically in an attempt to stimulate the female. Finally, the third phase refers to the actual copulation of the sea kraits. Copulation in sea kraits involves the insertion of the hemipenis of the male into the cloaca of the female.
In a study of mating groups on a small Fijian island, 51% were a male and female pair, and the remainder involved a female and 2 to 9 males. However, males do not appear to exhibit any interaction or competition. Also, in the vast majority of cases, only one male actively courts with a female while the others simply wait and maintain contact with the female. This may reveal two different strategies for male courtship in sea kraits. In one strategy, the male actively tries to stimulate the female until it is ready to copulate. In the other strategy, a male is opportunistic, waiting for the moment in which the female is ready to copulate, then rapidly aligning its cloaca with that of the female. Therefore, in contrast to some other snake species, reproductive success in males seems independent of their body size and strength. On the other hand, the attractiveness of females does have a direct correlation with body size as larger females are more frequently and intensely courted. Also, females rarely show any overt response during the courtship process however they may signal by waving their tails when they are ready to copulate.
Mating System: polyandrous
The breeding cycle for Laticauda colubrina varies geographically. In some populations, such as those in the Philippines, the breeding is aseasonal. However, in other populations of Laticauda colubrina, like those in Fiji and Sabah, it is seasonal with the main mating period occurring during the three month period from September to December. In these populations, the eggs typically hatch from June to August. Like other species of Laticauda, these sea kraits are oviparous and return to land to lay their eggs. However, their clutch size is also subject to geographical variation. For example, clutch size has been reported as 4 to 10 in Fiji and 14 to 20 in New Caledonia. Gestation period has been difficult to document because of asynchronous breeding in many populations of Laticauda colubrina. Also, little has been researched and understood in regards to hatchling sea kraits. Their average birth mass and time to independence is unknown and requires further research.
Breeding interval: The breeding interval of banded sea kaits varies between seasonally or aseasonally depending on geographic location.
Breeding season: Some populations of banded sea kaits are aseasonal and have no specific breeding interval. Populations in Fiji breed seasonally from September to December or January.
Range number of offspring: 4 to 20.
Range age at sexual or reproductive maturity (female): 1.5 to 2.5 years.
Average age at sexual or reproductive maturity (male): 1.5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; sexual ; fertilization ; oviparous
Parental investment for banded sea kraits has not been researched and is not known. Females lay eggs on the shore but it is unclear if they return to the sea or stay on shore to care for their eggs. It has been documented that females tend to spend more time on land than males do, but hypotheses of whether this is due to parental investment or a different, unrelated cause has not been tested. More research is required to determine by what modes and to what extent, parents care for their young in this species.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female)
Laticauda colubrina is a widespread, relatively abundant, and dangerously venomous sea krait ranging from the Andaman and Nicobar Islands and the Myanmar-Thai-Malaysian peninsula through the Indonesian archipelago to New Guinea and north to Palau, the Philippines, Taiwan, and the Ryukyu Islands, and southeastward along the island chain of the Solomon Islands, Vanuatu, Fiji, and Tonga. The yellow-banded sea krait clade is composed of the widespread L. colubrina plusL. guineai (found in a small region of southern Papua New Guinea), L. saintgironsi (endemic to New Caledonia, where it is common), and L. frontalis (a dwarf species endemic to Vanuatu, where it is sympatric with L. colubrina). Members of the L. colubrina complex forage on reefs by searching underwater crevices while tongue-flicking, apparently identifying prey by smell; their diet consists almost exclusively of various kinds of eels. (Heatwole et al. 2005)
In Myanmar, occurs in coastal waters, tidal rivers, ashore (especially along rocky coasts). Reportedly not commonly encountered in “Indian and Indo-Chinese waters” although it is not uncommon around Singapore. Although rare in the Bay of Bengal, it ispossibly not uncommon along the Myanmar coast and west coast of the Malaysian Peninsula. This species also occurs in coastal waters of Thailand, Malaysia, and western Indonesia as far east as Polynesia and north along the east Asian coast and Philippines to southern Japan. Individuals have been observed on a small uninhabited island around a mile off the Rakhine coast in the Bay of Bengal, where they were seen at rest during the day at low tide in rock crevices; surrounding waters were rich in large corals. In New Caledonia, these snakes are reportedly often found inshore under vegetation. They have been found at depths of greater than 60 m, but seem to prefer depths of less than 20 m. Laticauda colubrina are active both during the day and at night. (Leviton et al. 2003)
Ventrals large, one third to more than one half body width. Nostrils lateral; nasals separated by internasals; 21-25 longitudinal rows of imbricate scales at midbody; an azygous (single, not paired) prefrontal shield is usually present; rostral undivided; ventrals 213-243; subcaudals: males 37-47, females 29-35. Upper lip yellow. Total length: males 875 mm, females 1420 mm. Tail length: males 130 mm, females 145 mm.
(Leviton et al. 2003)
Colubrine sea krait
Yellow-lipped sea krait
Nattern-Plattschwanz
Marine waters of eastern India (Bay of Bengal) through Indo-Malaysia to New Guinea, Australia (tropical northeastern coast), New Zealand, and the Pacific Islands; Solomon Islands: southern Japan. Philippine Islands, Melanesia, Polynesia.
Holotype: ZMB 9078
Type-locality: None given, unknown.
The yellow-lipped sea krait (Laticauda colubrina), also known as the banded sea krait or colubrine sea krait, is a species of venomous sea snake found in tropical Indo-Pacific oceanic waters. The snake has distinctive black stripes and a yellow snout, with a paddle-like tail for use in swimming.
It spends much of its time under water to hunt, but returns to land to digest, rest, and reproduce. It has very potent neurotoxic venom, which it uses to prey on eels and small fish. Because of its affinity to land, the yellow-lipped sea krait often encounters humans, but the snake is not aggressive and only attacks when feeling threatened.
The head of a yellow-lipped sea krait is black, with lateral nostrils and an undivided rostral scale. The upper lip and snout are characteristically colored yellow, and the yellow color extends backward on each side of the head above the eye to the temporal scales.[3]
The body of the snake is subcylindrical, and is taller than it is wide. Its upper surface is typically a shade of blueish gray, while the belly is yellowish, with wide ventral scales that stretch from a third to more than half of the width of the body. Black rings of about uniform width are present throughout the length of the snake, but the rings narrow or are interrupted at the belly. The midbody is covered with 21 to 25 longitudinal rows of imbricated (overlapping) dorsal scales.[3] The dorsal and lateral scales can be used to differentiate between this species and the similar yellow-lipped New Caledonian sea krait, which typically has fewer rows of scales and scales that narrow or fail to meet (versus the yellow-lipped sea krait's ventrally meeting dark bands).[4] The tail of the snake is paddle-shaped and adapted to swimming.[5]
On average, the total length of a male is 875 mm (2 ft 10.4 in) long, with a 13 cm (5.1 in) long tail. Females are significantly larger, with an average total length of 1.42 m (4 ft 8 in) and a tail length of 145 mm (5.7 in).[3]
The yellow-lipped sea krait is widespread throughout the eastern Indian Ocean and Western Pacific. It can be found from the eastern coast of India, along the coast of the Bay of Bengal in Bangladesh, Myanmar, and other parts of Southeast Asia, to the Malay Archipelago and to some parts of southern China, Taiwan, and the Ryukyu Islands of Japan. The species is also common near Fiji and other Pacific islands within its range. Vagrant individuals have been recorded in Australia, New Caledonia, and New Zealand.[1] Six specimens have been found around the North Island of New Zealand between 1880 and 2005, suspected to have come from populations based in Fiji and Tonga.[4] It is the most common sea krait identified in New Zealand, and second-most seen sea snake after the yellow-bellied sea snake - common enough to be considered a native species, protected under the Wildlife Act 1953.[4]
The venom of this elapid, L. colubrina, is a very powerful neurotoxic protein, with a subcutaneous LD50 in mice of 0.45 mg/kg body weight.[6] The venom is an α-neurotoxin that disrupts synapses by competing with acetylcholine for receptors on the postsynaptic membrane, similar to erabutoxins and α-bungarotoxins.[7] In mice, lethal venom doses cause lethargy, flaccid paralysis, and convulsions in quick succession before death. Dogs injected with lethal doses produced symptoms consistent with fatal hypertension and cyanosis observed in human sea snake bite victims.[6]
Some varieties of eels, which are a primary food source for yellow-lipped sea kraits, may have coevolved resistance to yellow-lipped sea krait venom.[8] Gymnothorax moray eels taken from the Caribbean, where yellow-lipped sea kraits are not endemic, died after injection with doses as small as 0.1 mg/kg body weight, but Gymnothorax individuals taken from New Guinea, where yellow-lipped sea kraits are endemic, were able to tolerate doses as large as 75 mg/kg without severe injury.[9]
Yellow-lipped sea kraits are semiaquatic. Juveniles stay in water and on adjacent coasts, but adults are able to move further inland and spend half their time on land and half in the ocean. Adult males are more terrestrially active during mating and hunt in shallower water, requiring more terrestrial locomotive ability. Adult females, though, are less active on land during mating and hunt in deeper water, requiring more aquatic locomotive ability. Because males are smaller, they crawl and swim faster than females.[5]
Body adaptations, especially a paddle-like tail, help yellow-lipped sea kraits to swim. These adaptations are also found in more distantly related sea snakes (Hydrophiinae) because of convergent evolution, but because of the differences in motion between crawling and swimming, these same adaptations impede the snake's terrestrial motion. On dry land, a yellow-lipped sea krait can still move, but typically at only slightly more than a fifth of its swimming speed. In contrast, most sea snakes other than Laticauda spp. are virtually stranded on dry land.[5]
When hunting, yellow-lipped sea kraits frequently head into deep water far from land, but return to land to digest meals, shed skin, and reproduce. Individuals return to their specific home islands, exhibiting philopatry. When yellow-lipped sea kraits on Fijian islands were relocated to different islands 5.3 km away, all recaptured individuals were found on their home islands in an average of 30.7 days.[10]
Yellow-lipped sea kraits collected near the tip of Borneo had heavy tick infections.[11]
Hunting is often performed alone, but L. colubrina kraits may also do so in large numbers in the company of hunting parties of giant trevally and goatfish. This cooperative hunting technique is similar to that of the moray eel, with the yellow-lipped sea kraits flushing out prey from narrow crevices and holes, and the trevally and goatfish feeding on fleeing prey.[12]
While probing crevices with their heads, yellow-lipped sea kraits are unable to observe approaching predators and can be vulnerable. The snakes can deter predators, such as larger fish, sharks, and birds, by fooling them into thinking that their tail is their head, because the color and movement of the tail is similar to that of the snake's head. For example, the lateral aspect of the tail corresponds to the dorsal view of the head.[13][14]
Yellow-lipped sea kraits primarily feed on varieties of eels (of the families Congridae, Muraenidae, and Ophichthidae), but also eat small fish (including those of the families Pomacentridae and Synodontidae).[15] Males and females exhibit sexual dimorphism in hunting behavior, as adult females, which are significantly larger than males, prefer to hunt in deeper water for larger conger eels, while adult males hunt in shallower water for smaller moray eels. In addition, females hunt for only one prey item per foraging bout, while males often hunt for multiple items.[5][16] After hunting, yellow-lipped sea kraits return to land to digest their prey.[10]
The yellow-lipped sea krait is oviparous, meaning it lays eggs that develop outside of the body.[1]
Each year during the warmer months of September through December, males gather on land and in the water around gently sloping areas at high tide. Males prefer to mate with larger females because they produce larger and more offspring.[17]
When a male detects a female, he chases the female and begins courtship. Females are larger and slower than males, and many males escort and intertwine around a single female. The males then align their bodies with the female and rhythmically contract; the resulting mass of snakes can remain nearly motionless for several days.[17][18] After courtship, the snakes copulate for about an average of two hours.[17]
The female yellow-lipped sea kraits then lay as many as 10 eggs per clutch. The eggs are deposited in crevices where they remain until hatching.[19] These eggs are very rarely found in the wild; only two nests have been definitively reported throughout the entire range of the species.[1]
Because yellow-lipped sea kraits spend much of their time on land, they are often encountered by humans. They are frequently found in the water intake and exhaust pipes of boats.[19] They are also attracted to light and can be distracted by artificial sources of light, including hotels and other buildings, on coasts.[1]
Fewer bites from this species are recorded compared to other venomous species such as cobras and vipers, as it is less aggressive and tends to avoid humans.[15] If they do bite, it is usually in self-defense when accidentally grabbed. Most sea snake bites occur when fishermen attempt to untangle the snakes from their fishing nets.[20]
In the Philippines, yellow-lipped sea kraits are caught for their skin and meat; the meat is smoked and exported for use in Japanese cuisine.[1] The smoked meat of a related Laticauda species, the black-banded sea krait, is used in Okinawan cuisine to make irabu-jiru (Japanese: イラブー汁, irabu soup).[21]
The yellow-lipped sea krait (Laticauda colubrina), also known as the banded sea krait or colubrine sea krait, is a species of venomous sea snake found in tropical Indo-Pacific oceanic waters. The snake has distinctive black stripes and a yellow snout, with a paddle-like tail for use in swimming.
It spends much of its time under water to hunt, but returns to land to digest, rest, and reproduce. It has very potent neurotoxic venom, which it uses to prey on eels and small fish. Because of its affinity to land, the yellow-lipped sea krait often encounters humans, but the snake is not aggressive and only attacks when feeling threatened.
.jpg)
_3.jpg)
.jpg)
