Marine invertebrates exhibit a wide range of modifications to survive in poorly oxygenated waters, including breathing tubes as in
mollusc siphons. Fish have
gills instead of
lungs, although some species of fish, such as the
lungfish, have both.
Marine mammals (e.g. dolphins, whales,
otters, and seals) need to surface periodically to breathe air. (Full article...)
Steller's sea cow (Hydrodamalis gigas) is an
extinctsirenian described by
Georg Wilhelm Steller in 1741. At that time, it was found only around the
Commander Islands in the
Bering Sea between
Alaska and
Russia; its range extended across the North Pacific during the
Pleistoceneepoch, and likely contracted to such an extreme degree due to the
glacial cycle. It is possible indigenous populations interacted with the animal before Europeans. Steller first encountered it on
Vitus Bering's
Great Northern Expedition when the crew became shipwrecked on
Bering Island. Much of what is known about its behavior comes from Steller's observations on the island, documented in his posthumous publication On the Beasts of the Sea. Within 27 years of its discovery by Europeans, the slow-moving and easily-caught mammal was hunted into extinction for its meat, fat, and hide.
Some 18th-century adults would have reached weights of 8–10 t (8.8–11.0 short tons) and lengths up to 9 m (30 ft). It was a member of the family
Dugongidae, of which the 3 m (9.8 ft) long
dugong (Dugong dugon) is the sole living member. It had a thicker layer of
blubber than other members of the order, an adaptation to the cold waters of its environment. Its tail was forked, like that of whales or dugongs. Lacking true teeth, it had an array of white bristles on its upper lip and two
keratinous plates within its mouth for chewing. It fed mainly on
kelp, and communicated with sighs and snorting sounds. Steller believed it was a
monogamous and
social animal living in small family groups and
raising its young, similar to modern sirenians. (Full article...)
Jellyfish are mainly free-swimming marine animals with umbrella-shaped bells and trailing
tentacles, although a few are anchored to the seabed by stalks rather than being mobile. The bell can pulsate to provide propulsion for efficient
locomotion. The tentacles are armed with
stinging cells and may be used to capture prey and defend against predators. Jellyfish have a complex
life cycle. The medusa is normally the sexual phase, which produces
planula larvae; these then disperse widely and enter a sedentary
polyp phase, before reaching sexual maturity. (Full article...)
Livyatan is an
extinctgenus of macroraptorial
sperm whale containing one known species: L. melvillei. The genus name was inspired by the
biblical sea monster
Leviathan, and the species name by
Herman Melville, the author of the famous novel Moby-Dick about a white bull sperm whale. Herman Melville often referred to whales as "Leviathans" in his book. It is mainly known from the
Pisco Formation of
Peru during the
Tortonian stage of the
Mioceneepoch, about 9.9–8.9 million
years ago (mya); however, finds of isolated teeth from other locations such as
Chile,
Argentina,
United States (
California),
South Africa and
Australia imply that either it or a close relative survived into the
Pliocene, around 5mya, and may have had a global presence. It was a member of a group of
macroraptorial sperm whales (or "raptorial sperm whales") and was probably an
apex predator, preying on whales, seals and so forth. Characteristically of raptorial sperm whales, Livyatan had functional,
enamel-coated teeth on the upper and lower jaws, as well as several features suitable for hunting large prey.
Livyatan's total length has been estimated to be about 13.5–17.5 m (44–57 ft), almost similar to that of the modern
sperm whale (Physeter macrocephalus), making it one of the largest predators known to have existed. The teeth of Livyatan measured 36.2 cm (1.19 ft), and are the largest biting teeth of any known animal, excluding tusks. It is distinguished from the other raptorial sperm whales by the basin on the skull spanning the length of the
snout. The
spermaceti organ contained in that basin is thought to have been used in
echolocation and communication, or for ramming prey and other sperm whales. The whale may have interacted with the large extinct shark
megalodon (Otodus megalodon),
competing with it for a similar food source. Its extinction was probably caused by a cooling event at the end of the Miocene period causing a reduction in food populations. The geological formation where the whale has been found has also preserved a large assemblage of marine life, such as sharks and
marine mammals. (Full article...)
Baleen whales range in size from the 6 m (20 ft) and 3,000 kg (6,600 lb)
pygmy right whale to the 31 m (102 ft) and 190 t (210 short tons)
blue whale, the
largest known animal to have ever existed. They are
sexually dimorphic. Baleen whales can have streamlined or large bodies, depending on the feeding behavior, and two limbs that are modified into
flippers. The
fin whale is the fastest baleen whale, recorded swimming at 10 m/s (36 km/h; 22 mph). Baleen whales use their
baleen plates to filter out food from the water by either
lunge-feeding or skim-feeding. Baleen whales have fused
neck vertebrae, and are unable to turn their heads at all. Baleen whales have two
blowholes. Some species are well adapted for diving to great depths. They have a layer of fat, or
blubber, under the skin to keep warm in the cold water. (Full article...)
Sea urchins (/ˈɜːrtʃɪnz/) are
spiny, globular
echinoderms in the class Echinoidea. About 950 species of sea urchin are distributed on the seabeds of every ocean and inhabit every depth zone from the
intertidal seashore down to 5,000 meters (16,000 ft; 2,700 fathoms). The spherical, hard shells (
tests) of sea urchins are round and covered in spines. Most urchin spines range in length from 3 to 10 cm (1 to 4 in), with outliers such as the
black sea urchin possessing spines as long as 30 cm (12 in). Sea urchins move slowly, crawling with
tube feet, and also propel themselves with their spines. Although
algae are the primary diet, sea urchins also eat slow-moving (
sessile) animals.
Predators that eat sea urchins include a wide variety of fish,
starfish,
crabs,
marine mammals, and humans.
Like all echinoderms, adult sea urchins have fivefold symmetry, but their
pluteus larvae feature
bilateral (mirror) symmetry, indicating that the sea urchin belongs to the
Bilateria, along with
chordates,
arthropods,
annelids and
molluscs. Sea urchins are found in every ocean and in every climate, from the
tropics to the
polar regions, and inhabit marine benthic (sea bed) habitats, from rocky shores to
hadal zone depths. The fossil record of the Echinoids dates from the
Ordovician period, some 450 million years ago. The closest echinoderm relatives of the sea urchin are the
sea cucumbers (Holothuroidea), which like them are
deuterostomes, a clade that includes the
chordates. (
Sand dollars are a separate order in the sea urchin class Echinoidea.) (Full article...)
The ocean sunfish or common mola (Mola mola) is one of the largest bony fish in the world. It was misidentified as the heaviest bony fish, which was actually a different species, Mola alexandrini. Adults typically weigh between 247 and 1,000 kg (545 and 2,205 lb). The
species belongs to the Mola genus, one of three in the
Molidae family. It is native to
tropical and
temperate waters around the world. It resembles a fish head without a tail, and its main body is flattened laterally. Sunfish can be as tall as they are long when their
dorsal and ventral
fins are extended.
Adult sunfish are vulnerable to few natural predators, but
sea lions,
killer whales, and
sharks will consume them. Sunfish are considered a delicacy in some parts of the world, including
Japan,
Korea, and
Taiwan. In the
European Union, regulations ban the sale of fish and fishery products derived from the family
Molidae. Sunfish are frequently caught in
gillnets. (Full article...)
Image 7
Chrysomallon squamiferum from Longqi. Scale bar is 1 cm
Chrysomallon squamiferum,
commonly known as the scaly-foot gastropod, scaly-foot snail, sea pangolin, or volcano snail is a
species of deep-sea
hydrothermal-ventsnail, a marine
gastropodmollusc in the family
Peltospiridae. This vent-endemic gastropod is known only from deep-sea hydrothermal vents in the
Indian Ocean, where it has been found at depths of about 2,400–2,900 m (1.5–1.8 mi). C. squamiferum differs greatly from other deep-sea gastropods, even the closely related neomphalines. In 2019, it was declared
endangered on the IUCN Red List, the first species to be listed as such due to risks from
deep-sea mining of its vent habitat.
The shell is of a unique construction, with three layers; the outer layer consists of
iron sulphides, the middle layer is equivalent to the organic
periostracum found in other gastropods, and the innermost layer is made of
aragonite. The foot is also unusual, being armored at the sides with iron-mineralised
sclerites. (Full article...)
Marine mammal adaptation to an aquatic lifestyle varies considerably between species. Both cetaceans and sirenians are fully aquatic and therefore are obligate water dwellers. Pinnipeds are semiaquatic; they spend the majority of their time in the water but need to return to land for important activities such as
mating,
breeding and
molting. In contrast, both the sea otter and the polar bear are mostly terrestrial and only go into the water on occasions of necessity, and are thus much less adapted to aquatic living. The diets of marine mammals vary considerably as well; some eat
zooplankton, others eat fish, squid, shellfish, or seagrass, and a few eat other mammals. While the number of marine mammals is small compared to those found on land, their roles in various ecosystems are large, especially concerning the maintenance of marine ecosystems, through processes including the regulation of prey populations. This role in maintaining ecosystems makes them of particular concern as 23% of marine mammal species are currently threatened. (Full article...)
A tunicate is a marine
invertebrate animal, a member of the
subphylumTunicata (/ˌtjuːnɪˈkeɪtə/TEW-nih-KAY-tə). It is part of the
Chordata, a
phylum which includes all animals with
dorsal nerve cords and
notochords (including
vertebrates). The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their
myomeric segmentation, with the possible exception of the 'seriation of the gill slits'. However,
doliolids still display segmentation of the muscle bands.
Some tunicates live as solitary individuals, but others replicate by
budding and become
colonies, each unit being known as a
zooid. They are marine
filter feeders with a water-filled, sac-like body structure and two tubular openings, known as siphons, through which they draw in and expel water. During their
respiration and feeding, they take in water through the incurrent (or inhalant) siphon and expel the filtered water through the excurrent (or exhalant) siphon. Adult ascidian tunicates are
sessile, immobile and permanently attached to rocks or other hard surfaces on the ocean floor.
Thaliaceans (pyrosomes, doliolids, and salps) and
larvaceans on the other hand, swim in the
pelagic zone of the sea as adults. (Full article...)
Image 10
The orca (Orcinus orca), or killer whale, is a
toothed whale that is the largest member of the
oceanic dolphin family. It is the only
extant species in the genus Orcinus. Orcas are recognizable by their black-and-white patterned body. A
cosmopolitan species, orcas are found in diverse marine environments, from
Arctic to
Antarctic regions to tropical seas.
Orcas are
apex predators with a diverse diet. Individual populations often specialize in particular types of prey. This includes a variety of
fish,
sharks,
rays, and
marine mammals such as
seals and other
dolphins and whales. They are highly
social; some populations are composed of highly stable
matrilineal family groups (pods). Their sophisticated hunting techniques and vocal behaviors, often specific to a particular group and passed along from generation to generation are considered to be manifestations of
animal culture. (Full article...)
The class developed during the middle Cambrian, and underwent pulses of diversification during the
Ordovician period to become diverse and dominant in the
Paleozoic and
Mesozoic seas.
Small shelly fossils such as Tommotia were once interpreted as early cephalopods, but today these tiny fossils are recognized as
sclerites of larger animals, and the earliest accepted cephalopods date to the Middle Cambrian Period. During the Cambrian, cephalopods are most common in shallow near-shore environments, but they have been found in deeper waters too. Cephalopods were thought to have "undoubtedly" arisen from within the
tryblidiidmonoplacophoran clade. However genetic studies suggest that they are more basal, forming a sister group to the
Scaphopoda but otherwise basal to all other major mollusc classes. The internal phylogeny of Mollusca, however, is wide open to interpretation – see
mollusc phylogeny. (Full article...)
Image 8Dickinsonia may be the earliest animal. They appear in the fossil record 571 million to 541 million years ago. (from Marine invertebrates)
Image 9Diagram above contains clickable links
Image 10
Different bacteria shapes (
cocci,
rods and
spirochetes) and their sizes compared with the width of a human hair. A few bacteria are comma-shaped (
vibrio). Archaea have similar shapes, though the archaeon
Haloquadratum is flat and square.
The unit μm is a measurement of length, the
micrometer, equal to 1/1,000 of a millimeter
Image 18Conceptual diagram of faunal community structure and food-web patterns along fluid-flux gradients within
Guaymas seep and vent ecosystems. (from Marine food web)
Image 19Elevation-area graph showing the proportion of land area at given heights and the proportion of ocean area at given depths (from Marine habitat)
Image 20Biomass pyramids. Compared to terrestrial biomass pyramids, aquatic pyramids are generally inverted at the base. (from Marine food web)
Image 22A 2016
metagenomic representation of the tree of life using
ribosomal protein sequences. The tree includes 92 named bacterial phyla, 26 archaeal phyla and five eukaryotic supergroups. Major lineages are assigned arbitrary colours and named in italics with well-characterized lineage names. Lineages lacking an isolated representative are highlighted with non-italicized names and red dots. (from Marine prokaryotes)
Image 23A sleeping monk seal on the sandy beach with the ocean behind it (from Marine conservation)
Image 26This
algae bloom occupies sunlit
epipelagic waters off the southern coast of England. The algae are maybe feeding on nutrients from
land runoff or
upwellings at the edge of the continental shelf. (from Marine habitat)
Model of the energy generating mechanism in marine bacteria
(1) When sunlight strikes a rhodopsin molecule (2) it changes its configuration so a proton is expelled from the cell (3) the chemical potential causes the proton to flow back to the cell (4) thus generating energy (5) in the form of
adenosine triphosphate. (from Marine prokaryotes)
Image 33Ocean surface chlorophyll concentrations in October 2019. The concentration of chlorophyll can be used as a
proxy to indicate how many phytoplankton are present. Thus on this global map green indicates where a lot of phytoplankton are present, while blue indicates where few phytoplankton are present. – NASA Earth Observatory 2019. (from Marine food web)
Image 34Scanning electron micrograph of a strain of Roseobacter, a widespread and important genus of marine bacteria. For scale, the membrane pore size is 0.2 μm in diameter. (from Marine prokaryotes)
Image 39Oceanic pelagic food web showing energy flow from micronekton to top predators. Line thickness is scaled to the proportion in the diet. (from Marine food web)
Image 40Archaea were initially viewed as
extremophiles living in harsh environments, such as the yellow archaea pictured here in a
hot spring, but they have since been found in a much broader range of
habitats. (from Marine prokaryotes)
Image 41Some lobe-finned fishes, like the extinct Tiktaalik, developed limb-like fins that could take them onto land (from Marine vertebrate)
Image 42The deep sea
amphipodEurythenes plasticus, named after microplastics found in its body, demonstrating plastic pollution affects marine habitats even 6000m below sea level. (from Marine habitat)
Image 45Some representative ocean animal life (not drawn to scale) within their approximate depth-defined ecological habitats.
Marine microorganisms exist on the surfaces and within the tissues and organs of the diverse life inhabiting the ocean, across all ocean habitats. (from Marine habitat)
Image 46An in situ perspective of a deep pelagic food web derived from ROV-based observations of feeding, as represented by 20 broad taxonomic groupings. The linkages between predator to prey are coloured according to predator group origin, and loops indicate within-group feeding. The thickness of the lines or edges connecting food web components is scaled to the log of the number of unique ROV feeding observations across the years 1991–2016 between the two groups of animals. The different groups have eight colour-coded types according to main animal types as indicated by the legend and defined here: red, cephalopods; orange, crustaceans; light green, fish; dark green, medusa; purple, siphonophores; blue, ctenophores and grey, all other animals. In this plot, the vertical axis does not correspond to trophic level, because this metric is not readily estimated for all members. (from Marine food web)
Image 47
Estimates of microbial species counts in the three domains of life
Bacteria are the oldest and most biodiverse group, followed by Archaea and Fungi (the most recent groups). In 1998, before awareness of the extent of microbial life had gotten underway,
Robert M. May estimated there were 3 million species of living organisms on the planet. But in 2016, Locey and Lennon estimated the number of microorganism species could be as high as 1 trillion. (from Marine prokaryotes)
Image 48Tidepools on rocky shores make turbulent habitats for many forms of marine life (from Marine habitat)
Image 49Food web structure in the euphotic zone. The linear food chain large phytoplankton-herbivore-predator (on the left with red arrow connections) has fewer levels than one with small phytoplankton at the base. The microbial loop refers to the flow from the dissolved organic carbon (DOC) via heterotrophic bacteria (Het. Bac.) and microzooplankton to predatory zooplankton (on the right with black solid arrows). Viruses play a major role in the mortality of phytoplankton and heterotrophic bacteria, and recycle organic carbon back to the DOC pool. Other sources of dissolved organic carbon (also dashed black arrows) includes exudation, sloppy feeding, etc. Particulate detritus pools and fluxes are not shown for simplicity. (from Marine food web)
Image 50Microplastics found in sediments on the seafloor (from Marine habitat)
Image 52Ernst Haeckel's 96th plate, showing some marine invertebrates. Marine invertebrates have a large variety of
body plans, which are currently categorised into over 30
phyla. (from Marine invertebrates)
Image 53Anthropogenic stressors to marine species threatened with extinction (from Marine food web)
Image 55Cryptic interactions in the marine food web. Red:
mixotrophy; green:
ontogenetic and species differences; purple: microbial cross‐feeding; orange:
auxotrophy; blue: cellular carbon partitioning. (from Marine food web)
Image 56The distribution of anthropogenic stressors faced by marine species threatened with extinction in various marine regions of the world. Numbers in the pie charts indicate the percentage contribution of an anthropogenic stressors’ impact in a specific marine region. (from Marine food web)
Image 57
Diagram of a mycoloop (fungus loop)
Parasitic
chytrids can transfer material from large inedible phytoplankton to zooplankton. Chytrids
zoospores are excellent food for zooplankton in terms of size (2–5 μm in diameter), shape, nutritional quality (rich in
polyunsaturated fatty acids and
cholesterols). Large colonies of host phytoplankton may also be fragmented by chytrid infections and become edible to zooplankton. (from Marine fungi)
Image 62On average there are more than one million microbial cells in every drop of seawater, and their collective metabolisms not only recycle nutrients that can then be used by larger organisms but also catalyze key chemical transformations that maintain Earth’s habitability. (from Marine food web)
Image 65Estuaries occur when rivers flow into a coastal bay or inlet. They are nutrient rich and have a transition zone which moves from freshwater to saltwater. (from Marine habitat)
Image 70Schematic representation of the changes in abundance between trophic groups in a temperate rocky reef ecosystem. (a) Interactions at equilibrium. (b) Trophic cascade following disturbance. In this case, the otter is the dominant predator and the macroalgae are kelp. Arrows with positive (green, +) signs indicate positive effects on abundance while those with negative (red, -) indicate negative effects on abundance. The size of the bubbles represents the change in population abundance and associated altered interaction strength following disturbance. (from Marine food web)
Image 71Only 29 percent of the world surface is land. The rest is ocean, home to the marine habitats. The oceans are nearly four kilometres deep on average and are fringed with coastlines that run for nearly 380,000 kilometres.
Image 76In the open ocean, sunlit surface
epipelagic waters get enough light for photosynthesis, but there are often not enough nutrients. As a result, large areas contain little life apart from migrating animals. (from Marine habitat)
Solar radiation can have positive (+) or negative (−) effects resulting in increases or decreases in the heterotrophic activity of bacterioplankton. (from Marine prokaryotes)
Image 79Common-enemy graph of Antarctic food web. Potter Cove 2018. Nodes represent basal species and links indirect interactions (shared predators). Node and link widths are proportional to number of shared predators. Node colors represent functional groups. (from Marine food web)
Image 83A microbial mat encrusted with iron oxide on the flank of a
seamount can harbour microbial communities dominated by the iron-oxidizing
Zetaproteobacteria (from Marine prokaryotes)
Image 86Cnidarians are the simplest animals with cells organised into tissues. Yet the
starlet sea anemone contains the same genes as those that form the vertebrate head. (from Marine invertebrates)
Image 87Cycling of marine phytoplankton. Phytoplankton live in the photic zone of the ocean, where photosynthesis is possible. During photosynthesis, they assimilate carbon dioxide and release oxygen. If solar radiation is too high, phytoplankton may fall victim to photodegradation. For growth, phytoplankton cells depend on nutrients, which enter the ocean by rivers, continental weathering, and glacial ice meltwater on the poles. Phytoplankton release dissolved organic carbon (DOC) into the ocean. Since phytoplankton are the basis of marine food webs, they serve as prey for zooplankton, fish larvae and other heterotrophic organisms. They can also be degraded by bacteria or by viral lysis. Although some phytoplankton cells, such as dinoflagellates, are able to migrate vertically, they are still incapable of actively moving against currents, so they slowly sink and ultimately fertilize the seafloor with dead cells and detritus. (from Marine food web)
Image 90Sponges have no nervous, digestive or circulatory system (from Marine invertebrates)
Image 91Waves and currents shape the intertidal shoreline, eroding the softer rocks and transporting and grading loose particles into shingles, sand or mud (from Marine habitat)
Image 92Chytrid parasites of marine diatoms. (A) Chytrid sporangia on Pleurosigma sp. The white arrow indicates the operculate discharge pore. (B) Rhizoids (white arrow) extending into diatom host. (C) Chlorophyll aggregates localized to infection sites (white arrows). (D and E) Single hosts bearing multiple zoosporangia at different stages of development. The white arrow in panel E highlights branching rhizoids. (F) Endobiotic chytrid-like sporangia within diatom frustule. Bars = 10 μm. (from Marine fungi)
Image 94Phylogenetic tree representing bacterial OTUs from
clone libraries and
next-generation sequencing. OTUs from next-generation sequencing are displayed if the OTU contained more than two sequences in the unrarefied OTU table (3626 OTUs). (from Marine prokaryotes)
Mycoloop links between phytoplankton and zooplankton
Chytrid‐mediated trophic links between phytoplankton and zooplankton (mycoloop). While small phytoplankton species can be grazed upon by zooplankton, large phytoplankton species constitute poorly edible or even inedible prey. Chytrid infections on large phytoplankton can induce changes in palatability, as a result of host aggregation (reduced edibility) or mechanistic fragmentation of cells or filaments (increased palatability). First, chytrid parasites extract and repack nutrients and energy from their hosts in form of readily edible zoospores. Second, infected and fragmented hosts including attached sporangia can also be ingested by grazers (i.e. concomitant predation). (from Marine fungi)
Image 97Coral reefs provide marine habitats for tube sponges, which in turn become marine habitats for fishes (from Marine habitat)
Image 100Antarctic marine food web. Potter Cove 2018. Vertical position indicates trophic level and node widths are proportional to total degree (in and out). Node colors represent functional groups. (from Marine food web)
Image 101Reconstruction of an
ammonite, a highly successful early cephalopod that first appeared in the
Devonian (about 400
mya). They became extinct during the same
extinction event that killed the land dinosaurs (about 66 mya). (from Marine invertebrates)
Image 102Sandy shores provide shifting homes to many species (from Marine habitat)
Image 103Halfbeak as larvae are one of the organisms adapted to the unique properties of the microlayer (from Marine habitat)
Image 104Sea ice food web and the microbial loop. AAnP = aerobic anaerobic phototroph, DOC = dissolved organic carbon, DOM = dissolved organic matter, POC = particulate organic carbon, PR = proteorhodopsins. (from Marine food web)
Image 106The pelagic
food web, showing the central involvement of
marine microorganisms in how the ocean imports nutrients from and then exports them back to the atmosphere and ocean floor (from Marine food web)
Image 107The remains from the Exxon Valdez oil spill after the second treatment by oil spill workers in Alaska (from Marine conservation)
Image 117Phylogenetic and symbiogenetic tree of living organisms, showing a view of the origins of eukaryotes and prokaryotes (from Marine prokaryotes)
Image 22Ecosystem services delivered by
epibenthicbivalve reefs. Reefs provide coastal protection through erosion control and shoreline stabilization, and modify the physical landscape by
ecosystem engineering, thereby providing habitat for species by facilitative interactions with other habitats such as
tidal flat benthic communities,
seagrasses and
marshes. (from Marine ecosystem)
...
baleen from the
Mysticeti whales mouths was used to stiffen parts of women's stays and dresses, like corsets
... A typical shark has several hundred
teeth at any one time.
... The teeth of carnivorous sharks are not attached to the jaw, but embedded in their flesh. In many species, teeth are constantly replaced throughout the shark's life.
... the ‘strapped toothed’ whale is so called because in mature
males there are only two teeth in the bottom
jaw and these completely ‘strap’ the upper jaw, preventing it from opening more than a few centimetres. How these animals eat is unknown, but it may be that they stun their prey with high intensity
sound.
... the
Orca, is the fastest swimmer of all the cetaceans and can reach speeds of more than 50km/h while hunting.
... The
sea otter often keeps a stone tool in its armpit pouch.
Cuttlefish are sometimes called the
chameleon of the sea because of their remarkable ability to rapidly alter their
skin colour at will. Their skin flashes a fast-changing pattern as
communication to other cuttlefish and to
camouflage them from predators.