The black-banded sea krait (''Laticauda semifasciata''), also known commonly as the Chinese sea snake or erabu, is a largely amphibious

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of extremely venomous marine reptile in the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Laticaudinae,

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Elapidae Elapidae (, commonly known as elapids , from , variant of "sea-fish") 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 ...

( cobras, mambas, coralsnakes and their kin). It is found in much of the western

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

and some of the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it ...

. In

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

, it is known as ''erabu umi hebi'' ( :ja:エラブウミヘビ, 'erabu sea snake'); in

Okinawa most commonly refers to: * Okinawa Prefecture, Japan's southernmost prefecture * Okinawa Island, the largest island of Okinawa Prefecture * Okinawa Islands, an island group including Okinawa itself * Okinawa (city), the second largest city in th ...

, it is known simply as ''irabu''. This sea krait frequents

coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in group ...

habitats, where it can explore tight spaces for prey, as it has a short head, thick trunk, and no easily discernible neck. The tail is simply extended skin, spread wide like a fin, and unsupported by any bony projections from the vertebral column. The stomach is comparatively wide. Massing together near the shore, it breeds between narrow cracks in the reef and in caves. It is a nocturnal snake, rarely seen during the day. It breathes air; so it breaks the surface at least once every six hours. Too slow to pursue prey in open water, black-banded sea kraits hunt primarily by exploring the small spaces within coral reefs, in an effort to find hidden fish or other appropriately-sized animals. This meticulous scouring of the narrow nooks and crannies within a reef is similar to the hunting behaviors of some of the sea krait's main prey choices, such as the

moray eel Moray eels, or Muraenidae (), are a family (biology), family of eels whose members are found worldwide. There are approximately 200 species in 15 genera which are almost exclusively Marine (ocean), marine, but several species are regu ...

. Additionally, the black-banded sea krait has been observed foraging in mutually beneficial 'alliances' with

bluefin trevally The bluefin trevally (''Caranx melampygus''), also known as the bluefin jack, bluefin kingfish, bluefinned crevalle, blue ulua, omilu, and spotted trevally, is a species of large, widely distributed ocean, marine fish classified in the jack Famil ...

; the sea krait will scour the reef for potential prey as waiting groups of trevally watch, ready to pick-off any smaller, unwanted fish or

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

that are inadvertently flushed from the coral. The bite is highly venomous and paralyzes the prey. Females lay their eggs on land.

Distribution

The black-banded sea krait can be found in the warm waters of the western Pacific Ocean. Its typical distribution range includes China, Indonesia, Japan, Philippines, and Taiwan. However, researchers have recently found ''L. semifasciata'' in the waters surrounding southern South Korea. Its dispersion northward from its typical distribution range is attributed to climate change which has caused deterioration of its habitat.Park J, Kim I-H, Fong JJ, Koo K-S, Choi W-J, Tsai T-S, et al. (2017). "Northward dispersal of sea kraits (''Laticauda semifasciata'') beyond their typical range". ''PLoS ONE'' 12 (6): e0179871. https://doi.org/10.1371/journal.pone.0179871

Development

Males and females of the black-banded sea krait reach sexual maturity at snout-vent lengths (SVL) of , respectively. Females lay 3–7 eggs that hatch after 4–5 months. ''L. semifasciata'' can reach a total length (including tail) of .

Interaction with humans

Black-banded sea krait

venom Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

is reportedly ten times stronger than that of a

cobra COBRA or Cobra, often stylized as CoBrA, was a European avant-garde art group active from 1948 to 1951. The name was coined in 1948 by Christian Dotremont from the initials of the members' home countries' capital cities: Copenhagen (Co), Brussels ...

; however, as with the vast majority of

venomous snake ''Venomous snakes'' are species of the suborder Serpentes that are capable of producing venom, which they use for killing prey, for defense, and to assist with digestion of their prey. The venom is typically delivered by injection using hollow ...

species, the black-banded sea krait generally does not aggressively strike at humans unless it is cornered or threatened (or otherwise maliciously provoked), preferring to conserve its energy and venom supplies for hunting purposes, reacting defensively only as a very last resort. Despite its potent venom, which is concentrated in the snake's venom glands (behind the eyes), the meat of the ''erabu'' snake is a winter staple food in southern Japan, where it is believed to replenish a female's womanhood or increase fertility. Irabu soup, or ''irabu-jiru'' ( :ja:イラブー汁), is said to taste like

miso is a traditional Japanese seasoning. It is a thick paste produced by fermenting soybeans with salt and kōji (the fungus ''Aspergillus oryzae''), and sometimes rice, barley, seaweed, or other ingredients. It is used for sauces and spreads; p ...

and a bit like

tuna A tuna (: tunas or tuna) is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae ( mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bul ...

. This dish was a favorite of the royal court of the

Ryukyu Kingdom The Ryukyu Kingdom was a kingdom in the Ryukyu Islands from 1429 to 1879. It was ruled as a Tributary system of China, tributary state of Ming dynasty, imperial Ming China by the King of Ryukyu, Ryukyuan monarchy, who unified Okinawa Island t ...

; it is thought to have

analeptic An analeptic, in medicine, is a type of central nervous system (CNS) stimulant. The term ''analeptic'' typically refers to respiratory stimulants (e.g., doxapram). Analeptics include a wide variety of medications used to treat depression, attenti ...

properties. During certain warm years, the sea snakes are drawn ''en masse'' to the

sea cave A sea cave, is also known as a littoral cave, a type of cave formed primarily by the wave action of the sea. The primary process involved is erosion. Sea caves are found throughout the world, actively forming along present coastlines and as re ...

s and tide pools of the coastal Ryukyu cliffs, in search of fresh water to drink and possibly to mate. It is in these cryptic spots where, by cover of darkness (and usually guided only by lantern light), elderly women—who are the most experienced at preparing ''irabu-jiru''—explore the dangerous caverns in pursuit of black-banded sea kraits, which the ladies catch with their bare hands. Some areas may contain hundreds of the snakes, some engaged in active breeding balls, yet the women hike through the caves barefoot or with minimal protective gear. As with the handling of any venomous snake species, the sea snakes are grabbed quickly behind the head, as to avoid any potential envenomation. They are placed in a cloth bag, alive, and later quickly dispatched and prepared in a simple broth with

kombu ''Konbu'' (from ) is edible kelp mostly from the family Laminariaceae and is widely eaten in East Asia. It may also be referred to as ''dasima'' () or ''haidai'' (). Kelp features in the diets of many civilizations, including Chinese and Icela ...

or other edible

kelp Kelps are large brown algae or seaweeds that make up the order (biology), order Laminariales. There are about 30 different genus, genera. Despite its appearance and use of photosynthesis in chloroplasts, kelp is technically not a plant but a str ...

, and possibly a bit of pork.

Distribution

Development

Interaction with humans

References

Further reading