fauna

biomedicalephemera:

Humboldt Squid/Jumbo Squid

Loligo gigas [now Dosidas gigas] 

The Humboldt squid is among the largest of the squid, despite their lifespan of just under one year. Other giant squids have a lifespan estimated to be around five years at a minimum, and don’t reach their maximum size until near the end of their life. One of the major sources of food for Humboldt squid is other Humboldt squids, which is believed to contribute significantly to their fast growth.

All of the suckers of the Humboldt are ringed with sharp, flesh-tearing teeth, and when squid are feeding, they’ve been known to be very aggressive towards scuba divers. Outside of feeding time (generally dusk to dawn), the squid are generally non-aggressive creatures.

Like many squid, the Humboldt has chromatophores in its skin, allowing for rapid color changes. When they feed or are in distress (such as when they’re caught by fishers), they flash bright red. This led to one of their first colloquial names - El diablo rojo - the Red Devil.

Voyage dans l’Amerique Meridionale: Tome Neuvieme. Alcide d’Orbigny, 1847.

Fish Use ‘Sign Language’ to Help Out Hunting Buddies

by Douglas Main

Two types of fish have been shown to use gestures, or sign language, to help one another hunt. This is the first time these types of gestures have been found to occur in animals other than primates and ravens.

Both types of fish, grouper and coral trout, are known for hunting cooperatively with other kinds of animals. Whereas the grouper hunts with giant moray eels and a fish called the Napoleon wrasse, coral trout partner up with octopuses to snag prey. A study published last week in the journal Nature Communications found that the fish are able to “point” their heads toward prey, to help out their hunting buddies.

After observing the fish in the wild for many hours, the researchers found that when a prey fish escaped its hunting party, a grouper occasionally moved over the place where the fugitive prey was hiding. The grouper would then rotate its body so that its head faced downward, and it would shake its head back and forth in the direction of the potential meal, in what researchers call a “headstand” signal. Coral trout make a similar sign, the researchers found…

(read more: http://www.livescience.com/29120-fish-use-sign-language-to-hunt.html?cmpid=514627)

(photo: Klaus Jost., Univ. of Mich. - ADW)

montereybayaquarium:

Here’s something to look for on your next visit:

pharaoh cuttlefish eggs! We always like it when animals reproduce on exhibit, as it’s a sign that we’ve created a healthy environment. Hope you’re having a great weekend!

Learn more about cuttlefish.

Paper Nautilus (Argonauta argo)

Photograph by Robert Sisson, National Geographic

Females of this unusual octopus species sequester themselves in thin, translucent shells with which they drift across the open seas. Paper nautiluses, also called argonauts, secrete the shells to serve as cases for their eggs—but it has recently been discovered that they also function as air-trapping ballast tanks, which allow the cephalopods to hang effortlessly in the water column without sinking. This is the only species known to use surface air bubbles to effectively control the animals’ buoyancy.

(via: National Geo)

Jumbo Squid-Cam Uncovers Secrets of Elusive Creature

by Megan Gannon

To see firsthand how an elusive species of jumbo squid lives, scientists have strapped video cameras to the carnivorous sea creature in the eastern Pacific.

The footage has helped reveal some remarkable secrets of the Humboldt squid: They are capable of amazing bursts of speed, up to nearly 45 mph (72 km/h); they “talk” to each other by changing their body color; and they hunt in big synchronized groups.

Humboldt squid (Dosidicus gigas) — which can grow to more than 6 feet (2 meters) in length and 100 lbs (45 kg) in weight — have razor-sharp beaks and toothed suckers. Mass strandings of the species and reports of aggression toward humans have spooked beachgoers for decades, but the jumbo squid are not man-eaters — they usually feed on small fish and plankton that are no more than a few inches in length, though they sometimes cannibalize each other…

(read more: Live Science)                 (photo: Stanford Univ.)

astronomy-to-zoology:

Joubin’s Squid (Joubiniteuthis portieri)

….is a small species of squid found in the Atlantic Ocean, Pacific Ocean and rarely in the Indian Ocean. This species is noted for its extremely thin mantle, long tail and long arms. Like the bigfin squid it is thought that the squid dangles its long tentacles in the water column in hopes of catching passing food.

Phylogeny

Animalia-Mollusca-Cephalopoda-Teuthida-Oegopsina-Joubiniteuthidae-Joubinieteuthis-portieri

Image Source

scienceyoucanlove:

Antarctic Octopus Living Testament To Global Warming

The octopus, formerly known as both a delicacy food item and for being thrown onto the ice at hockey games, now has a new recognition: a living testament to the effects of global warming.

Genetic information from an Antarctic octopus species adds to a growing body of evidence of at least a partial collapse of the West Antarctic Ice Sheet (WAIS) during a previous interglacial period (like during the Eemian interglacial some 125,000 years ago).

Members of Turquet’s octopuses (pictured) tend to live in one place and only move to escape predators. This led to the understanding that specimens from areas on either side of Antarctica would be genetically different. What scientists found after examining specimens from each side of the WAIS was that both populations were genetically nearly identical.

Dr Phill Watts, from the University’s Institute of Integrative Biology, explains: “We expected to find a marked difference between Turquet’s octopuses living in different regions of the ocean, particularly between areas that are currently separated by approximately 10,000 km of sea. These creatures don’t like to travel and so breeding between the populations in the Ross and Weddell Seas [now separated by those 10,000 km of ocean] would have been highly unusual.”

read more and see references here

‘Giant Squid’ Are Indeed All One Species

by Stephanie Pappas

Though they roam the deep sea around the globe, enigmatic giant squid are all part of the same species, new research finds.

The new study reveals that the genetic diversity of giant squid (Architeuthis) is remarkably low — far lower than that of other marine species examined, said study researcher Tom Gilbert of the University of Copenhagen. The findings suggest that the squid intermingle and mate across the globe.

“The results are extremely surprising,” Gilbert told LiveScience.

Giant squid are mysterious creatures. They dwell in the deep ocean, making them difficult to observe in their natural habitats. In fact, no one had observed a live giant squid in the wild until 2004. The first video of a live giant squid wasn’t released until this year. The animals appear to grow as long as 60 ft (18 m) and are carnivores that prey on fish and other squid…

(read more: Live Science)                     (photo: Mark Norman)

Baby Boom at American Zoos:  Pacific Giant Octopus