Yellow-lipped sea krait | |
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Yellow-lipped sea krait in Malaysia | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Squamata |
Suborder: | Serpentes |
Family: | Elapidae |
Genus: | Laticauda |
Species: | L. colubrina |
Binomial name | |
Laticauda colubrina (Schneider, 1799) | |
Synonyms [2] | |
The yellow-lipped sea krait (Laticauda colubrina), also known as the banded sea krait or colubrine sea krait, is a species of venomous 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]
Elapidae is a family of snakes characterized by their permanently erect fangs at the front of the mouth. Most elapids are venomous, with the exception of the genus Emydocephalus. Many members of this family exhibit a threat display of rearing upwards while spreading out a neck flap. Elapids are endemic to tropical and subtropical regions around the world, with terrestrial forms in Asia, Australia, Africa, and the Americas and marine forms in the Pacific and Indian Oceans. Members of the family have a wide range of sizes, from the 18 cm (7.1 in) white-lipped snake to the 5.85 m king cobra. Most species have neurotoxic venom that is channeled by their hollow fangs, and some may contain other toxic components in varying proportions. The family includes 55 genera with around 360 species and over 170 subspecies.
The common krait is a venomous snake species belonging to the genus Bungarus in the Elapidae family. It is native to the Indian subcontinent and is responsible for the majority of snakebites affecting humans in India, Pakistan, and Bangladesh.
The banded krait is an extremely venomous species of elapids endemic to Asia, from Indian Subcontinent through Southeast Asia to Southern China. With a maximum length exceeding 2 m, it is the longest krait with a distinguishable gold and black pattern. While this species is generally considered timid and docile, resembling other members of the genus, its venom is highly neurotoxic which is potentially lethal to humans. Although toxicity of the banded krait based upon murine LD50 experiments is lower than that of many other kraits, its venom yield is the highest due to its size.
The blue-lipped sea krait, also known as the blue-banded sea krait or common sea krait, is a species of venomous sea snake in the subfamily Laticaudinae of the family Elapidae. It is found in the Indian and Western Pacific Oceans.
Sea snakes, or coral reef snakes, are elapid snakes that inhabit marine environments for most or all of their lives. They belong to two subfamilies, Hydrophiinae and Laticaudinae. Hydrophiinae also includes Australasian terrestrial snakes, whereas Laticaudinae only includes the sea kraits (Laticauda), of which three species are found exclusively in freshwater. If these three freshwater species are excluded, there are 69 species of sea snakes divided among seven genera.
Aipysurus laevis is a species of venomous sea snake found in the Indo-Pacific. Its common names include golden sea snake, olive sea snake, and olive-brown sea snake.
Sea kraits are a genus of venomous snakes, Laticauda. They are semiaquatic, and retain the wide ventral scales typical of terrestrial snakes for moving on land, but also have paddle-shaped tails for swimming. Unlike fully aquatic ovoviviparous sea snakes, sea kraits are oviparous and must come to land to digest prey and lay eggs. They also have independent evolutionary origins into aquatic habitats, with sea kraits diverging earlier from other Australasian elapids. Thus, sea kraits and sea snakes are an example of convergent evolution into aquatic habitats within the Hydrophiinae snakes. Sea kraits are also often confused with land kraits , which are not aquatic.
The katuali or flat-tail sea snake is a species of venomous sea snake in the family Elapidae. The species is found only in the waters of the Pacific Islands nation of Niue.
The many-banded krait, also known as the Taiwanese krait or the Chinese krait, is a highly venomous species of elapid snake found in much of central and southern China and Southeast Asia. The species was first described by the scientist Edward Blyth in 1861. Averaging 1 to 1.5 m in length, it is a black or bluish-black snake with many white bands across its body. The many-banded krait mostly inhabits marshy areas throughout its geographical distribution, though it does occur in other habitat types.
The black-banded sea krait, also known commonly as the Chinese sea snake or erabu, is a largely amphibious species of venomous marine reptile in the subfamily Laticaudinae, family Elapidae. It is found in much of the western Pacific Ocean and some of the Sea of Japan. In Japan, it is known as erabu umi hebi ; in Okinawa, it is known simply as irabu.
Crocker's sea snake is a species of venomous snake in the subfamily Laticaudinae of the family Elapidae. The species is native to Oceania.
The extant (living) reptiles of New Zealand consist of numerous species of terrestrial lizards and the lizard-like tuatara, and several species of sea turtles and sea snakes. All but one species are native to New Zealand, and all but one of the terrestrial species are endemic to New Zealand, that is, they are not found in any other country. Many species of foreign reptiles enter New Zealand through accidental importation or smuggling, but only the Australian native Lampropholis delicata has become established in the wild, and it is considered an invasive pest.
The yellow-bellied sea snake is a venomous species of snake from the subfamily Hydrophiinae found in tropical oceanic waters around the world except for the Atlantic Ocean. For many years, it was placed in the monotypic genus Pelamis, but recent molecular evidence indicates it lies within the genus Hydrophis.
The New Caledonian sea krait is a species of venomous snake in the subfamily Laticaudinae of the family Elapidae. The species is native to the waters around New Caledonia.
Laticauda guineai is a species of venomous sea snake in the family Elapidae. The species, which was first described by Heatwole, Busack and Cogger in 2005, is native to waters off southern New Guinea.