Recreating the spectacular pose many dinosaurs adopted in death might involve following the simplest of instructions: just add water.

When palaeontologists are lucky enough to find a complete dinosaur skeleton – whether it be a tiny Sinosauropteryx or an enormous Apatosaurus – there’s a good chance it will be found with its head thrown backwards and its tail arched upwards – technically known as the opisthotonic death pose. No one is entirely sure why this posture is so common, but Alicia Cutler and colleagues from Brigham Young University in Provo, Utah, think it all comes down to a dip in the wet stuff.

Cutler placed plucked chickens – both fresh and frozen – on a bed of sand for three months to see if desiccation would lead to muscle contractions that pulled the neck upwards – a previously suggested explanation for the death pose. The chickens decayed without contorting. When seven other chickens were placed into cool, fresh water, however, their necks arched and their heads were thrown back within seconds. Sustained immersion of the birds for up to a month slightly increased the severity of the pose, but the major movement of the head occurred almost immediately.

The result contrasts with a study carried out in 2007 by Cynthia Marshall Faux at the Museum of the Rockies in Bozeman, Montana, and at the University of California in Berkeley. The pair found that salty water did not alter the pose of dead quails. They concluded that the arched back seen in so many fossils was instead the result of the expiring dinosaur’s final death throes () – an idea that was first suggested by pathologist Roy Moodie in 1918.

Why dunking dead birds in water produced different results in the two studies is not clear. It’s possible that the salt content of the water was a factor – but Cutler has confidence in her freshwater study: “Although the roads to the opisthotonic death pose are many, immersion in water is the simplest explanation.�

Cutler presented the findings at the in Las Vegas, Nevada, earlier this month.

Black is always in fashion. The prehistoric bird Archaeopteryx just hit the trend early. In a presentation at the 71st annual meeting of the Society of Vertebrate Paleontology in Las Vegas, Nevada, last Thursday, Brown University graduate student Ryan Carney offered a first glimpse of the true colour of one the famous creature’s feathers.

For years, palaeontologists have speculated about Archaeopteryx‘s colour scheme, without knowing for sure. Artists have painted it in every shade from tan and rusty brown, to bright greens and blues.

All this speculation could soon end, with new ways to detect prehistoric colours. In 2008 Jakob Vinther, then a graduate student at Yale University, and colleagues discovered the secret by examining microscopic, pigment-creating structures called melanosomes inside a Cretaceous feather from Brazil. The patterns of the tiny features corresponded to those in modern birds, opening the way for studies identifying the colours of dinosaurs.

Last year, for example, Quanguo Li of Beijing’s Museum of Natural History, Vinther, and collaborators painted the full plumage pattern of the feathered dinosaur Anchiornis. A dinosaur very much like Archaeopteryx, Anchiornis was primarily black and white with a splash of red feathers on its head ().

The subject of Carney’s research was a single – but hugely significant – feather. First described in 1861 by German palaeontologist Hermann von Meyer, it is 150 million years old and the first Archaeopteryx ever to be identified. The discovery of a dinosaur-like skeleton with feather traces from the same deposits soon revealed the magnificent creature the feather came from.

In Las Vegas, Carney reported that the specimen was probably a covert feather &ndash part of the Archaeopteryx wing which would have partly covered the primary feathers used for flight.

As for the colour, Carney and colleagues used scanning electron microscopy and energy-dispersive X-ray analyses to detect the melanosomes, then compared this data to similar feathers in a database of 87 modern bird species. The feather, he says, was most probably black. While the full colour pattern of Archaeopteryx has yet to be uncovered, Carney noted that melanosomes on the black feather have structural properties which may have strengthened the feathers for the demands of flight. The miniscule structures which hide the secrets of prehistoric colour were not just for show.

Conference references: R. Carney, et al. 2011. Black Feather Colour in Archaeopteryx. 2011 , p 84