The Broadclub Cuttlefish Of Havelock Island, India (Sepia Latimanus)
- ThePersaudCatalog
- Jun 10
- 8 min read
Updated: Jun 11
This month's article series will be discussing the beautiful & esteemed Havelock Island of India’s Andaman Sea.
Havelock Island is approximately 324.26 nautical miles (373.151744 miles, or 600.52952 kilometers) off the coast of the mainland country of Thailand. Havelock Island gets its name from Sir Henry Havelock, was British Major-General who served in India.
Havelock Island is a part of the Ritchie Archipelago, in the Western Central Andaman Sea. It is important to mention that the Andaman Sea is located in the eastern Bay of Bengal. Due to its location, the island's primary language is Bengali. The island was recently renamed to Swaraj Island, but for this article, we will refer to it as Havelock Island.
Havelock Island is most well known for its beautiful beaches, forests, & exquisite marine life. The island is surrounded by coral reefs, which are incredibly biodiverse. The thickly wooded forests on the island clash with the sandy beaches, which create a beautiful & unique environment. These coral reefs are fringing, & can be seen by all who roam the beaches.
Snorkelling & Scuba diving are extremely popular for this reason, so much so that this island is widely considered a small slice of paradise. A strange creature that roams these reefs is the Broadclub Cuttlefish.
The Broadclub Cuttlefish is a species of cuttlefish found in the western Indian & Western Pacific Oceans. They have been observed breeding off the coast of Okinawa, as well as Guam. This species may also be found off the coast of Madagascar, but scientists widely regard sightings off the coast of Madagascar as misidentifications.
This species of cuttlefish is found most commonly in coral reefs. It is the second-largest cuttlefish species on earth. This creature is brown & white or yellow, with spots. During breeding, though, the males may change in colouration to a darker brown. Additionally, they may change in depth, as they can manipulate their skin to create bumps to blend in with rocks.
In this article, we will discuss the Discovery & Life, the Mating Procedures, Practices, Cycles, Tactics, & Strategies, the Distribution, & the Scientific Detailings of the Broadclub Cuttlefish. With that being said, let us delve into this Cambrian-like creature.
The Discovery & Life Of The Broadclub Cuttlefish
The Broadclub Cuttlefish was discovered in 1832. It was discovered by Jean René Constant Quoy, a French naval surgeon & zoologist, & Joseph Paul Gaimard, a French naval surgeon & naturalist.
The Broadclub Cuttlefish's mantle can be up to 19.685 pounds (50 centimeters) long, & can weigh up to 22.0462 pounds (10 kilograms). They grow for their entire lives, & don’t stop until their death. Unfortunately, we cannot find any information on the lifespan of this creature, but the majority of cuttlefish do not live for over 2 years.
Cuttlefish are extremely intelligent among ocean creatures. They are a part of the cephalopod class, which is known as one of the smartest classes of oceanic animals. Unfortunately, they are not as smart as octopi, but are smarter than squids. They can learn patterns & skills, such as lifting objects or pressing buttons. They also can exhibit emotions, & affectionate behaviours. Their memory is superb, as they can remember what they have eaten even hours later.
It is unknown how long this species has existed for exactly, but the first cuttlefish appeared in the Miocene Epoch, about 23 million years ago. The reason for there being such poor documentation on this species is that soft-bodied animals cannot fossilize easily.
Cuttlefish are not dangerous to humans or aggressive, unless provoked. They may be defensive towards their eggs. Though they do have venom used for hunting, the venom is not dangerous to humans, & does not affect humans very much. They will rarely choose to interact with humans, as they are very timid creatures. Even in captivity, it may take days or occasionally weeks for a cuttlefish to eat in front of the aquarium caretaker.
This species is not usually territorial, except during mating season when the males will defend their breeding territory. These territories are usually near the shallow parts of coral reefs. They are very solitary aside from mating, & migrating to the shoreline. Occasionally, groups of cuttlefish will migrate to the shoreline. They can communicate with one another by changing the patterns on their skin, which is extremely remarkable.
These cuttlefish swim by shooting water out from their guts, & using the fins that span their entire mantle to steer. They are extremely agile, & can maneuver efficiently as well as make rapid movements. Unfortunately, no scientist has measured how fast they can swim. Buoyancy is controlled by a shell inside the cuttlefish, which is similar to that of a swim bladder.
Like the majority of cephalopods, they sleep by turning parts of their brain off, while remaining half awake to fend off predators.
Their main diet consists of small fish, bivalves, worms, & occasionally other cephalopods. They are diurnal hunters, & hunt by confusing their prey with their skin. They flash patterns on their skin in strange ways to distract the animal, then inject it with a neurotoxic venom. They may be cannibalistic, but this is not confirmed. Cuttlefish see prey by feeling ripples, & by sight. It is unclear how much they eat per day, but cuttlefish tend to eat much more than their squid counterparts. Their metabolism is very fast, as they need to swim constantly. Their main reef predators are Dolphins, Sharks, Seals, Waterfowl, & Possibly other Cuttlefish.
In the reef, they are constantly changing colour & depth, so they don’t have on uniform colour & shape. The IUCN has assessed their population, but unfortunately, there was not enough data to categorize them as anything. For this reason, they are not actively being monitored by conservationists.
The Mating Tactics, Procedures, Practices, Cycles, & Strategies Of The Broadclub Cuttlefish
The Broadclub Cuttlefish produces via sexual reproduction. This species is not hermaphroditic, & has two distinct sexes. Their breeding system is polyandrous & they complete the breeding ritual by external fertilization. The males will pass away shortly after they copulate, though the females may live long enough to copulate a second time.
The females will fully mature between 10 & 16 months, & the males in 12 to 18 months. They do have a particular breeding season, which is from Early January to Late May. The gestational period for this species is between 38, & 44 days long.
The females will alert the females that they are ready to breed by making their skin dark grey, extending their tentacles, & making their mantle harder. The males will also display a light grey skin colour. Once he sees a female he desires to breed with, he reaches his tentacles out in the water towards her. He will curl the tips of his tentacles, & caress the female to get her attention. If she responds, they will continue, & if she doesn’t, he will swim around her.
Once the ritual has been initiated, the males will insert their tentacles into the female to inject their sperm. The males have a special tentacle called a hectocotylus, which is used to store sperm sacs. The female will store these sacs in her egg sac, & will then look for a suitable place to lay them. She will lay them against some kind of hard surface, such as a large rock or a coral reef. After this, the females may go on to mate again, or they will pass away. After the second time, the females will promptly pass away upon the hatching of their eggs.
The parents have no part in the children’s lives, & the children have to fend for themselves as soon as they are born. Between 10 & 30 eggs will be laid for each egg group.
The Distribution Of The Broadclub Cuttlefish
The Broadclub Cuttlefish is primarily found in the Indian, & Western Pacific Oceans. It is unclear how far west in the Indian Ocean they are found, & they may be found farther than Mauritius. Reefed areas tend to attract them as these areas are the most as these areas have the most prey. They rarely migrate, unless it is to the shoreline. In Egypt, the Maldives, Indonesia, Thailand, & Myanmar, divers have compiled a list of places where this animal is most commonly found. The link to this list is as follows: https://www.notroublesjustbubbles.com/marine-life/broadclub-cuttlefish.
The Scientific Details of the Broadclub Cuttlefish
By far, the most interesting thing about the Cuttlefish is its ability to change the depth & colour of its skin at will.
The Broadclub Cuttlefish can do this by having a few specialized kinds of skin cells found in cephalopods, known as Chromatophores, & Iridophores. Chromatophores work by absorbing certain wavelengths to create colour, & are controlled by contracting muscles. Chromatophores are located just above the Iridophores. The Iridophores work by scattering light, & are controlled directly by the nervous system.
This species does produce venom, but it is not toxic to humans. Cuttlefish do not have teeth, they instead, like all cephalopods, have a beak at the base of their tentacles. This beak is used for snapping the skeletons of fish & exoskeletons of crustaceans. Unlike their fellow cephalopods, they cannot fit in very tight spaces due to their inner shell.
Cuttlefish have a total of 3 hearts, much like Octopi or Squid. They have 2 branchial hearts which pump blood to their gills. At this point, the blood will take in oxygen & be sent off to the systemic heart. After this, the systemic heart will pump the blood all over the body. Their blood is also blue instead of red. The reason for this is due to a copper-rich protein known as Hemocyanin existing in their blood. The existence of this protein in their blood causes their blood to be blue. This is very similar to the iron in Hemoglobin in human blood. This blue blood exists in all cephalopods. If used properly, this blood can be used as a pigment or a dye. Cuttlefish also have superb intelligence, & can learn things from their caretakers. They can distinguish one human from another, & to express curiosity, affection, & anxiousness.
Cuttlefish have one of the largest brain-to-body ratios of all oceanic creatures, which is one of the primary factors contributing to their intelligence. In addition to their intellect, they have a strong long-term & short-term memory, being able to recall events from weeks before.
Their phylum is known as Mollusca. Mollusca is the 2nd largest phylum, just behind Arthropoda. Mollusca is, however, the largest marine phylum as it comprises approximately 23% of all documented marine species. The three most commonly found features defining modern species categorized under molluscs are the following: a mantle with a significant cavity used for breathing & excretion, the presence of a radula, and the structure of the nervous system.
Their class is Cephalopoda. This class includes almost all species of cuttlefish, octopi, squid, & nautilus.
Their Order is Sepiida, which is the order of all Cuttlefish. All Cuttlefish have an inner shell, known as a cuttlebone, which is used to control buoyancy.
Their family is Sepiidae, which is one of the largest families of cuttlefish.
Their Genus is Sepia. This genus contains some of the most well-known Cuttlefish, & encompasses cuttlefish with an ellipsoid shape. Their binomial name is Sepia latimanus.
Directories / Credits
Citation No. 1: “Sepia Latimanus”, Written By Hannah Markowitz, & Published at an Unknown Date. Published by Animal Diversity Web. Retrieval Date: November 15th, 2023.
Citation No. 2: “Broadclub Cuttlefish”, Written By Unknown & Published at an Unknown Date. Published by Oceana. Retrieval Date: November 15th, 2023.
Citation No. 3: “Broadclub Cuttlefishes, Sepia Latimanus”, Written by Unknown & Published at an Unknown Date. Published by the Marine Biological Conservation Society. Retrieval Date: November 15th, 2023.
Citation No. 4: “Cephalopod chromatophores: neurobiology and natural history, Written by B. Messenger, & Published in November of 2001. Published by National Library of Medicine. Retrieval Date: November 15th, 2023.
Citation No. 5: “The Best Kind Of Aging Brain”, Written By Kathrine J. Wu, & Published at an Unknown Date. Published By the Atlantic. Retrieval Date: November 15th, 2023.
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