They evolved from snakes that lived on the land. Some sea snakes still have some of the behaviour and traits of their ancestors, such as "Laticauda", which can move a little on land. Most sea snakes are unable to move on the ground at all, but they are well adapted to living in the water.
Sea snakes are found in warm coastal waters from the Indian Ocean to the Pacific. They live in the tropical and warm regions, but not in the Atlantic Ocean, or the North American coast above the Gulf of California.
Most sea snakes grow to sizes between 1.2m and 1.4m, some can reach 2m or more. "Hydrophis cyanocinctus" reach 2.5m to 3m. They reach a weight of about 0.8 -1.3 kg, at a size of 1.8m. In most cases, females are larger than males.
All sea snakes have paddle-like tails and many have laterally compressed bodies – they look somewhat like eels. However, unlike fish, they do not have gills and must come to the surface regularly to breathe. Nevertheless, they are among the most completely aquatic of all air-breathing vertebrates. Among this group are species with some of the most potent venoms of all snakes. Some have gentle dispositions and bite only when provoked, while others are much more aggressive.
Sea snakes have special nostrils that can close when they go underwater and open when they come up to breathe, like the blowhole of a whale (scientists call these "valved" nostrils). The nostrils are found high up on the head so that the entire snake can stay under the water when they come up to breathe. In its search for food, a sea snake may remain under water for a long time. To do this, sea snakes have evolved a single lung that almost is as long as the whole body.
Most sea snakes are able to breathe through their skin. This is unusual for reptiles, because their skin is normally thick and scaly. Experiments with the black-and-yellow sea snake, "Pelamis platurus" (a pelagic species), have shown that this species can get about 20% of its oxygen in this manner, which allows for longer dives.
Like other land animals that have adapted to life in a marine environment, sea snakes swallow considerably more salt than their relatives living on land. They do this through their diet and when they inadvertently swallow sea water. Kidney function in birds and reptiles is too weak to remove enough salt. In birds, such as penguins, salt is removed through nasal glands. The marine iguanas of the Galapagos Islands use the same mechanism. Sea turtles have lacrimal glands that allow them to produce very salty tears. But in sea snakes, glands under and around the tongue let them expel salt with their tongue action.
Most sea snakes prey on fish, especially eels. The latter stiffens and dies within seconds when bitten. One species prefers molluscs and crustaceans, such as prawns. Some reef dwelling species have small heads and thin necks, making it possible for them to get small eels from the soft bottom where they hide.
"Pelamis platurus" has a venom more potent than any other terrestrial snake species in Costa Rica. The snake is very common in the waters of the western coast of Costa Rica. Despite this, few human deaths have been reported. Nevertheless, all sea snakes should be handled with great caution.
When bites occur, only a small amount of venom is injected. The symptoms caused by the venom may seem slight at first. There is usually little or no swelling involved, and it is rare for any nearby lymph nodes to be affected. The most important symptoms are a rapid breakdown of skeletal muscle tissue and paralysis. Early symptoms include headache, a thick-feeling tongue, thirst, sweating, and vomiting. Symptoms that can occur after 30 minutes to several hours after the bite include generalized aching, stiffness, and tenderness of muscles all over the body. This is followed later on by symptoms typical of other elapid attacks: a progressive paralysis of muscles. Paralysis of muscles involved in swallowing and respiration can be fatal. After three to eight hours, myoglobin may start to show up in the blood plasma. This is a result of muscle breakdown. It can cause the urine to turn a dark reddish, brown, or black in color, and eventually lead to kidney failure. After six to twelve hours, severe hyperkalemia can lead to cardiac arrest. The hyperkalemia is also the result of muscle breakdown.
Archduke
The title of Archduke (feminine: Archduchess) (German: "Erzherzog", feminine form: "Erzherzogin") is a rank above Duke and under King. It is very rare. It was used only by males of the House of Habsburg.
The English word is recorded only since 1530, derived from Middle Latin "archidux", from "arch(i)-" (primary or chief) + "dux" 'duke' .
Archduke ("Erzherzog") is a title distinct from Grand Duke ("Großherzog" or "Großfürst") that is used in some other German royal houses and still in sovereign Luxemburg.
Trench warfare
Trench warfare is a war tactic, or way of fighting. It was commonly used on the Western Front in the First World War but also at other wars and other places.
In trench warfare, the two sides fighting each other dug trenches in a battlefield. These trenches had many different parts, such as places for sleeping, for headquarters, for storage, and for artillery and machine guns. Between the front trenches on a battlefield, was an area called "no man's land". This area was often covered with barbed wire and land mines. Soldiers on either side would try to cross the no man's land to get to the enemy's trench and attack. Tanks were commonly used to cross this land.
Trench warfare was used because it gave soldiers cover while defending themselves against attack. It also gave soldiers bunks to sleep in, although the bunks were very unclean and uncomfortable.
World War I started in 1914 and ended in 1918. While fighting, soldiers needed self-defense. So, they dug holes. The holes were two meters deep. These holes were called trenches. Most soldiers fought in the trenches. The trenches were not very far apart. For example, they could have been as short as thirty meters in between each trench. This open space was called No Man’s Land. Death was frequent, even when there was no fighting (for example, by diseases). This was called trench warfare.
Trench warfare was also an important part of the Iran-Iraq War.
The trenches were dirty. The cold, wet and unsanitary conditions made many soldiers sick. For example, "trench foot" was a fungal disease. It rotted people’s feet off. Lice spread throughout the trenches. They spread a disease called trench fever. It caused fevers and a severe pain to the head. Rats invaded the trenches and spread disease everywhere. The brown rats were the more hated kind. They ate human remains. Some grew to be as big as cats. The mud was very thick. Some men disappeared into the mud because it was so thick.
The trenches had a horrible smell. This was because of the lack of bathing, the dead bodies, and the overflowing toilets. The first thing a new recruit would notice on the way to the Frontline was the smell. Bodies were rotting in shallow graves, men had not washed in weeks because there were no facilities, cesspits were overflowing, and creosol or chloride of lime was used to stave off the constant threat of disease and infection. They could smell cordite, the lingering odour of poison gas, rotting sandbags, stagnant mud, cigarette smoke, and cooking food. Although overwhelmed at first, new arrivals soon got used to it and eventually became part of the smell with their own body odour.
Front line trenches were usually about seven feet deep and six feet wide. The front of the trench was known as the parapet. The top two or three feet of the parapet and the parados (the rear side of the trench) would consist of a thick line of sandbags to absorb any bullets or shell fragments.