The oceans cover more than 70 per cent of our planet’s surface, and are home to some very weird sea creatures.
Often living at great depth, they sometimes look a bit nightmarish but are mostly harmless to humans.
Life is thought to have started in the oceans and many of these creatures have been around for millions of years, long before our ancestors stepped out into the savannah.
Indeed we have only explored a tiny portion of the oceans and are making new discoveries every year.
Here are 10 very weird sea creatures from the ocean’s depths.
The Goblin Shark (mitsukurina owstoni) has a long sword-like nose and a rather odd overall appearance.
However, things really get freaky when it attacks prey. The goblin shark has a set of extendable jaws that rush out, Alien style, to snatch passing fish.
The shark is usually around 10-13ft in length but a 20ft one was caught a few years back, so some definitely get bigger.
Goblin Sharks tend to live fairly deep down amongst the canyons and cliffs under the ocean. Sometimes underground earthquakes will drive dozens to the shallow waters…happy days!
Although they look very scary, Goblin Sharks pose no threat to humans as they are rarely seen and prey on small fish and shrimps.
The black swallower (chiasmodon niger) is a deep-sea fish that really does live up to its name.
Although it is fairly small with a maximum length of around 10in (25cm), it can swallow fish up to ten times its own mass and, in extreme cases, four times its length!
Its lower jaw is able to swing down allowing the black swallower to gulp down prey bigger than its own head. It is then thought to ‘walk’ its jaws along its meal until the unfortunate creature is swallowed.
The black swallower’s stomach is distensible allowing it to hold these huge meals whilst they are digested.
Sometimes it will eat something so big that the meal starts to decompose before it is fully digested, the resulting gas build-up forcing the swallower to the surface. Nice!
A common fish, the black swallower is found throughout the tropics and subtropics.
The blobfish (psychrolutes marcidus) is another deep-sea creature that provokes disgust in some and has been dubbed the world’s ugliest animal.
Found in the waters around Australia and New Zealand this small fish lives at depths of 2,000-3,900ft (600-1,200m). Down this deep the pressure can be up to 120 times that on the surface.
The blobfish’s flesh is mostly made up of a jelly-type mass, which allows it to float just above the sea floor without much effort. It feeds on creatures like shellfish that drift into its path.
When under pressure at depth the blobfish looks fairly normal, so it’s maybe undeserving of its ‘World’s Ugliest Animal’ nickname.
Only when it is brought to the surface does it lose all its shape.
The blobfish is at risk of becoming an endangered species due to bottom trawling.
Found in the Atlantic and Pacific oceans, the unusual frilled shark (chlamydoselachus anguineus) is often dubbed a living fossil due to its many primitive features with its eel-like body and and terrifying set of teeth.
The name derives from the appearance of its gills, which start under its throat. It has a long and flexible jaw lined with 25 rows of razor sharp hooked teeth, meaning it can swallow prey whole and prevent them escaping.
Some researchers believe the shark hunts prey by bending itself then launching towards its target like a snake striking.
Despite not being commercially fished, the frilled shark is rated as near threatened due to its very low reproduction rate.
The predatory tunicate (megalodicopia hians) is an unusual and pretty weird deep-sea invertebrate.
The strangely elegant creature attaches itself to the walls of deep-sea canyons or the sea floor at depths of between 660 and 3,200ft (200 to 975m).
It then waits for tiny animals and zooplankton to drift near its mouth, which then closes surprisingly quickly.
Sloane’s viperfish (chauliodus sloani) is a very strange-looking creature found in the depths of tropical and subtropical oceans.
Around 8-14in (20-35cm) in length, it has the world record for the fish with the largest teeth in comparison to its head.
When its jaws are closed the teeth overlap them and in order to actually swallow anything it has to open its mouth so wide its jaws go vertical!
It can even impale its prey on its teeth just by swimming towards them at speed.
Don’t worry though, the Sloane’s viperfish prefers the deep depths, being found down as far as 8,000 feet (2,500m).
The vampire squid is a fearsome looking deep-sea creature found in tropical and temperate oceans all over the world.
Typically it is around 30cm in length, with half that being its body. It has eight spiny arms connected with webs of skin. But rather than any blood-sucking, it is the animal’s dark to reddish colour together with its large blue eyes that give the vampire squid its name.
Found at depths between 2,000 to 3,000ft (610 to 915m) it actually feeds on the remains of zooplankton and other small creatures.
It uses two feeding filaments, which can be up to eight times its length, to trap particles.
Its body is covered in photophores, allowing it to create flashes of light of varying intensity and size. Though unlike many cephalopods it cannot change skin color.
The animal’s scientific name is vampyroteuthis infernalis, literally vampire squid of Hell!
Don’t have nightmares though, as it is actually of a fairly gentle nature and performs a useful function in the ecosystem.
The polychaete worm is a type of segmented worm, a group that includes more than 10,000 species including the lugworm and sandworm.
They are found at every depth and can thrive in any temperature, from the coldest ocean regions to volcanic vents on the deep ocean floor.
Some were even found by the robotic probe Nereus when it explored the deepest part of the ocean yet found.
Generally they are less than 10cm in length, but some are as small as 0.03in (1mm) and others as long as 9ft 10in (3m).
They have a fairly sophisticated head compared with other annelids, though their eyes are typically fairly primitive.
Ghost sharks, or chimaeras, are not actually sharks, though they share a 400 million-year-old common ancestor.
The fossil record shows they were once widespread but now they are mainly found in the deepest parts of the ocean.
They prefer a temperate climate and are generally found at around 8,500 ft (2,600m), though a few have been found at shallower depths.
Chimaeras can grow up to nearly 5ft (1.5m) in length and have many venomous spines in front of their dorsal fin, used for defense.
Unlike sharks they do not have rows of replaceable teeth. Instead they have three large tooth plates they use for grinding.
They are sometimes known as rat fish, spookfish and rabbit fish.
The Deepstaria reticulum is one of the most mysterious genus of jellyfish and although they are not rare they are unusual to be found intact, due to their fragile nature.
They have an unusually thin and wide bell, a bit like a fan, often of a deep and striking color.
Their close relative the Deepstaria enigmatica has a bell more like a lava lamp which moves in the current creating a rather beautiful effect.
Deepstaria are usually found around the Antarctic at depths of 2,600 to 5,900ft (800 to 1,800m) but a few have been spotted near the UK, often during commercial drilling.
Weird sea creatures: In summary
Well that’s our selection of weird sea creatures for now. We think the most interesting thing about them is that despite many looking like something from a nightmare, they are mostly harmless to humans and indeed our actions are far more dangerous to them.
Our oceans are still relatively unexplored and who knows what other weird and wonderful creatures are still to be discovered in the vast depths from which life first emerged.