In general, shallow-water cephalopods typically grow fast, live for only a year or two, and die soon after spawning. Deep-water cephalopods are more likely to spawn multiple times and live for at least several years. This may help them cope with limited food and the challenges of finding mates. Here are a few of the surprising observations about cephalopod sex that Morse and Huffard describe in their article:.
Doryteuthis opalescens squids mate in large swarms, with females laying their eggs on in masses on the sandy seafloor. A female Abdopus aculeatus octopus mates with two males in a laboratory setting. The cross-section of a modern Nautilus left , the last living genus representing a subclass called the nautiloids, reveals the many chambers, including the latest and largest chamber in which the adult Nautilus lives.
The same features are seen in the straight, conical shells of fossil ancestors preserved in limestone. On right is a living Nautilus in its shell. Although the giant squid is one of the largest predators in the ocean, it is considered a tasty meal by an even larger predator, the sperm whale.
Remains of the horny beaks of giant squids have been found in the stomachs of sperm whales, and sucker marks from the tentacles of giant squids are found on whales. Nautilus is found in the southwestern Pacific Ocean and Indian Ocean. It lives at a depth of several hundred meters during the day, but will come up as shallow as 5 meters 16 feet during the night to hunt.
Planispheral shells of the Nautilus can be cut into two halves that are bilaterally symmetrical. In contrast, conispheral shells such as most snails coil along a vertical axis forming a pointed spire, and are not symmetrical.
As the living Nautilus grows, it secretes a larger extension of the shell and seals off the older segments of the shell with thin, curved walls called septa. These concave-forward septa form the chambers of the Nautilus. A fleshy cord called the siphuncle connects the chambers. The empty chambers are filled with gas at about atmospheric pressure.
The animal can regulate its buoyancy by slowly pumping fluids in and out of the empty chambers through the siphuncle. The Nautilus ' shell is thin, only 1 or 2 millimeters less than a tenth of an inch , but extremely strong. A strong shell is necessary to resist the great pressures experienced at the depth where Nautilus lives.
Experiments with living Nautilus have shown that the shell can endure pressure at depths of up to meters feet before the shell implodes. Clarkson, Euan N.
Invertebrate Palaeontology and Evolution. Indeed, nearly all cephalopods a grouping that includes squid, nautilus, octopus, and cuttlefish are only known to live one or two years, which this octopus beats during its brooding time alone.
Ultimately, this means that Graneledone boreopacifica is also the longest lived octopus. This obviously had an impact on the octopus, and researchers watched as she grew paler, lost weight, her skin sagged, she her eyes grew cloudy.
Researchers believe that the octopus was able to survive the lack of food because of her inactivity, which kept her metabolic demands low. Scientists associated with the study also note that it is possible that the octopus nibbled on some passing crabs or consumed some of the damages eggs; however, no such feedings were actually witnessed and the octopus did not eat a crab that the team offered her. Ultimately, this level of dedication is extreme even for octopuses.
Previously, the longest brooding octopus was the deep-sea Bathypolypus arcticus, which had a brooding time of some 14 months in the lab. For most shallow-water species, the brooding time lasts some three months. Obviously, the 53 month vigil of the Graneledone boreopacifica blows the shallow-water species out of the water. However, this particular octopus lives deep beneath the waters—some 1, meters 4, feet deep in the Monterey Submarine Canyon. Even if that demand continued exponentially, it would be legal: None of the plus known species of octopus is listed under the Convention on International Trade in Endangered Species of Fauna and Flora CITES , which regulates cross-border trade in wildlife, or the U.
This may reflect a lack of information—for example, in the case of the mimic octopus. Another celebrated octopus presents a different concern. All octopuses probably carry some venom, but only the various golf ball-size blue-ringed species , which range from southern Japan to Australia, are known to pack a lethal dose.
Their saliva contains the potent nerve toxin tetrodotoxin, the same compound that makes California newts, harlequin frogs, and fugu pufferfish liver so deadly. One blue ring can carry enough to kill 10 or more humans.
Blue-ring bites occur each year in Australia, but timely, vigorous artificial respiration usually prevents fatalities; only three have been confirmed during the past century, none involving aquariums. More blue-ring fatalities may go unidentified, however, because the bites are painless and the mode of death—respiratory paralysis—can be caused by other toxins and nerve, muscle, and lung conditions.
Caldwell recounts a close escape. He had recruited his teenage daughter to help him scour reef samples for the mantis shrimp he was studying off Australia's Lizard Island. She felt "something soft and squishy" inside one rock oyster shell.
Rather than crawling for cover like most octopuses, [the octopus] reared up while pulling back her first two pair of arms [and] exposing her mouth. It was very clear to me that here was an octopus ready to bite This was a potentially lethal blue-ringed octopus that my unsuspecting daughter had handled just minutes earlier. Imports of blue rings to the U. Other vendors still offer them, even online. Ross is now with the Albright Laboratory, a coral-reef research and restoration facility affiliated with the aquarium.
Custom ordering also enables responsible vendors to evaluate purchasers and advise them about best practices. Any downturn also reflects the efforts of Wood and other experts to educate hobbyists and vendors about the costs and hazards of keeping these demanding super-mollusks. In addition to their high prices and expensive diets—heavy on live crabs and shrimp— octopuses need large, escape-proof tanks with ample hiding places, unassailable fixtures to withstand their powerful arms and inquisitive tampering, and no fish or other companions they'll eat them.
The purchase is also a short-term investment. Most species live only one to two years, and a newly imported octopus may have just weeks left.
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