Pharaoh cuttlefish ( (Barratt and Allcock, 2009)) have a large geographic range, reaching as far east as Zanzibar, as far west as Australia, and as far north as Japan. They span the Indian Ocean, the Persian Gulf, the Red Sea, the Arabian Sea, and the Andaman Sea.
Pharaoh cuttlefish live in fairly shallow waters, ranging as deep as 130 m. They tend to rise up in the water column at night to hunt for crustaceans and small fish. The depth ranges in which they congregate depend on their geographic location. In the Andaman Sea and the Gulf of Thailand they are found in waters about 10 to 40 m deep. This ranges are also affected by the seasons, as they are migratory. During mating season, off the coast of Hong Kong, they are found at depths of 40 to 80 m. (Barratt and Allcock, 2009)
Pharaoh cuttlefish can grow to about 80 cm in mantle length, with males larger than the females on average. The largest recorded male was 80 cm long and weighed about 5 kg, while the maximum record for females was 50 cm long, weighing 2 kg. Both of these individuals were found in the Persian gulf.
Pharaoh cuttlefish share the same color changing mechanism as other cuttlefish species, and can even change the texture of their skin. The color changing mechanism of pharaoh cuttlefish is controlled by muscular rings that expand and contract around color-filled sacs called chromophores. The resting color for pharaoh cuttlefish is generally a solid color that alternates between white and dark brown, but they can also present a white-and-brown mottled color with a brown circle in the center. ("Cephalopods", 1996; Ketabi, 2016; King, 2018a; King, 2018b; Mangold and Young, 2016)
Pharaoh cuttlefish, like other cuttlefish, have large eyes with protective cornea layers and sharp beaks located at the base of their mantles. Their internal organs, both digestive and reproductive, are located in their mantles. Their mantles also contain an internal shell, or cuttlebone. Cuttlebones are oblong in shape with a rounded end on the posterior side and a point on the anterior side. Cuttlebones are porous and allow cuttlefish to control their buoyancy by changing the amount of gas present within their cuttlebones. Pharaoh cuttlefish are dorsoventrally flattened with long, oval-shaped bodies that are bordered by narrow fins. These narrow fins extend the entire mantle until they reach the posterior end, where they do not connect. The ventral tentacles of pharaoh cuttlefish tend to be longer and broader when compared to their retractible arms. These tentacles also contain suckers that are in a 2 to 4 series. ("Cephalopods", 1996; Ketabi, 2016; King, 2018a; King, 2018b; Mangold and Young, 2016)
Mature male pharaoh cuttlefish reach mantle lengths of about 7 cm, whereas females reach about 8.6cm. Note that maximum lengths differ by geographic region, because pharaoh cuttlefish are a species complex. This means that they may not be one species, but rather a group of closely related species that are too difficult to distinguish.
Young pharaoh cuttlefish are fairly well developed at birth and even exhibit most adult behaviors at mantle lengths of around 8 mm (a hatchling size). The weight increase for pharaoh cuttlefish is low within the first 60 days of life, but in the 5th and 6th month of life they gain weight exponentially. Pharaoh cuttlefish reach sexual maturity within 4 to 5 months of its hatching. (Andrews, 2005; Raid and Halim, 2015)
There are two distinct sexes, male and female, in pharaoh cuttlefish. They tend to mate in the spring and summer, where they migrate to shallower waters. They perform elaborate courtship routines that involve males changing their normal mottled color to a zebra-striped pattern in order to attract females. Males flash their zebra-striped pattern to notify other males that they are also males, while females remain mottled in color. Competition between males can be intense, and in some cases may even become violent. After competing, one male remains with the female to mate. In most cases this is the larger male. The victorious male will then stroke the female between her eyes, and will changes his color back to the normal mottled pattern, notifying his readiness to mate. If another male tries to interrupt mating, the defending male will again flash the zebra-striped pattern, but only on the side facing the other male so he does not startle the female. (Andrews, 2005; "Cephalopods", 1996; Hanlon and Ament, 1999; King, 2018a)
Pharaoh cuttlefish mate through internal fertilization, where males insert spermatophores into the buccal membrane of a female. They do this by using a modified arm called a "hectocotylus" that continuously breaks open the spermatophores ensuring they attach to the buccal membrane. In most males, approximately 140 spermatophores are attached to the female in a single mating episode. After mating is complete, females lay eggs 1 to 2 cm long and covered in ink to darken them. Both males and females can mate several times, but after spawning both sexes will die. (Andrews, 2005; "Cephalopods", 1996; Hanlon and Ament, 1999; Raid and Halim, 2015)
Pharaoh cuttlefish are precocial, meaning that offspring are well developed and independent when born. This means that there is no further parental involvement of the offspring other than the initial protection of the eggs by placing them in a relatively safe environment. (Andrews, 2005; Raid and Halim, 2015)
Average lifespan for pharaoh cuttlefish is about 240 days, or 8 months. They die after they have completed spawning. (King, 2018b)
Pharaoh cuttlefish actively hunt at night hide during the day; this goes for hatchlings and adults. Young also hatch at night. Pharaoh cuttlefish are fairly solitary creatures that only come together to mate. Prey recognition is innate in hatchlings. By the time they reach mantle lengths of about 8 mm, hatchlings present behaviors common of adults. These common behaviors include locomotion, prey capture, ejection of ink, and sudden changes in color due to environmental factors or emotions.
Pharaoh cuttlefish can propel themselves rapidly through the water using jet propulsion. They do this by filling their mantle cavity with water and then quickly expelling the water through their siphon. This behavior can be used to either escape from predators or quickly ambush unsuspecting prey. The use of their siphons for a quick escape can also be paired with an ejection of ink in order to disorientate potential predators. Pharaoh cuttlefish specifically have demonstrated a unique arm-flapping behavior when approaching their prey. They raise their first pair of arms while wrinkling and darkening them. Simultaneously, they bend their second and third pair of arms as if they are on a joint. This behavior has been seen right before they attacks their prey. (Andrews, 2005; Mangold and Young, 2016; Okamoto, et al., 2017)
The home range for pharaoh cuttlefish is about 10 to 40 m, and 40 to 80 m during mating season. Their range is vastly affected by the geographic region and can go as deep as about 130 m. (Barratt and Allcock, 2009)
Pharaoh cuttlefish communicate primarily using visual cues such as their unique ability to change the color and texture of their skin. While their color is generally a molted pattern, they can change it to a zebra-striped pattern to convey aggression. This zebra striping can also be used to represent gender during mating season. This unique ability is also paired with other visual cues like their swimming posture and the position of their tentacles.
Since pharaoh cuttlefish are fairly solitary creatures, most of their intraspecific communication is conducted during mating season. Their interspecific communication is limited to escaping predators using ink or camouflage, and when changing their color and body position to approach their prey. ("Cephalopods", 1996; Hanlon and Ament, 1999; Okamoto, et al., 2017)
Pharaoh cuttlefish eat mysids (order Mysida) of all sizes as well as brine shrimp (Artemia), crabs, molluscs, fish, and sometimes even other cuttlefish. Like other cuttlefish, they are ambush predators. This means that they are extremely adept at camouflaging themselves. They hide themselves by changing their texture and color to blend in with their surroundings and hide from unsuspecting prey. They go about attacking their prey in two ways: they either open their eight arms and shoot out their two tentacles to quickly capture their prey, or they pounce on their prey using their arms to hold them in place. In both of these cases, pharaoh cuttlefish use their beaks and radulae to tear into their prey. Adults and hatchlings hunt at night, and hatchlings begin to hunt when they reach mantle lengths of about 8 mm. However, they can recognize prey as soon as they hatch. (Andrews, 2005; Dunlop, 2003; King, 2018a)
Predators of pharaoh cuttlefish include sharks, dolphins, seals, seabirds, whales, and even other cuttlefish. In order to escape their predators, pharaoh cuttlefish use jet propulsion and ink ejection to make a quick exit while simultaneously disorientating potential predators. They also avoid predation by changing their coloration and texture to better match their surroundings, which helps them avoid being spotted. (Dunlop, 2003; King, 2018a; Zych, 2015)
Pharaoh cuttlefish expend large amounts of energy mating and escaping predators. These actions expend a lot of metabolic energy, and thus require a large amount of energy, acquired through hunting. Pharaoh cuttlefish have a large range of prey they feed upon and a large dispersion pattern. This makes them crucial consumers that fill various ecological niches. (Barratt and Allcock, 2009; King, 2018a)
Pharaoh cuttlefish are commonly bred and fished for consumption and research. Their ink has been used for various homeopathic medicinal practices, such as cures for menstrual cramps and even depression. People have also been known to keep pharaoh cuttlefish as pets. Though the most common use for pharaoh cuttlefish is the extraction of their cuttlebone for pet birds to easily gain calcium. (Andrews, 2005; Davis, 2009; "Sepia (Cuttlefish ink)", 2013)
Pharaoh cuttlefish have no known adverse effects on human populations.
Pharaoh cuttlefish are considered data deficient by the IUCN, but they do face threats to their populations. The increase of ocean acidification due to increased carbon dioxide levels within the atmosphere is a major threat not only to pharaoh cuttlefish, but also other marine organisms. The increased levels of CO2 has also been shown to increase cuttlebone density, which negatively affects their buoyancy control. They are also commonly fished and may be subjected to overfishing, thus depleting their populations. Current conservation efforts include fishing quotas in Yemen, and reducing carbon emissions around the world. (Barratt and Allcock, 2009)
Pharaoh cuttlefish are one of two cuttlefish species that have been found to completely regenerate limbs after amputation. It takes about 39 days for their appendages to completely regenerate, including new chromatophores, suction cups, normal shape, and complete use for social communication and predation. The regeneration process is consistent and statistically predictable throughout the whole species. (Tressler, et al., 2014)
Sydney Wayne (author), Colorado State University, Kate Gloeckner (editor), Colorado State University, Galen Burrell (editor), Special Projects.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
the nearshore aquatic habitats near a coast, or shoreline.
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
a substance used for the diagnosis, cure, mitigation, treatment, or prevention of disease
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.
fertilization takes place within the female's body
makes seasonal movements between breeding and wintering grounds
imitates a communication signal or appearance of another kind of organism
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
active during the night
found in the oriental region of the world. In other words, India and southeast Asia.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the business of buying and selling animals for people to keep in their homes as pets.
an animal that mainly eats fish
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.
mainly lives in oceans, seas, or other bodies of salt water.
offspring are all produced in a single group (litter, clutch, etc.), after which the parent usually dies. Semelparous organisms often only live through a single season/year (or other periodic change in conditions) but may live for many seasons. In both cases reproduction occurs as a single investment of energy in offspring, with no future chance for investment in reproduction.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
uses sight to communicate
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