Cave bears as omnivorous as modern bears

Rather than being gentle giants, new research reveals that Pleistocene cave bears ate both plants and animals and competed for food with the other contemporary large carnivores of the time: hyaenas, lions, wolves, and our own human ancestors.

Cave bears (Ursus spelaeus) have long fascinated palaeontologists and anthropologists, given the abundance of their large skeletal remains in Pleistocene hibernation caves across western Eurasia. For the past 30 years, studies of their bones and teeth, and especially the nitrogen isotopes in their bone protein, have concluded that they were largely vegetarian.

The interpretation of them as vegetarian has evoked an image of gentle giants, feeding on berries and roots. However, new nitrogen isotope data from the Peştera cu Oase in southwestern Romania shows otherwise. Although many of these cave bears appear to have been largely vegetarian, the Oase bears and scattered individuals from other cave sites show that they were sometimes as omnivorous as modern brown bears, including North American Kodiak and grizzly bears.

Reference: Richards, M.P., Pacher, M., Stiller, M., Quilès, J., Hofreiter, M., Constantin, S., Zilhão, J., Trinkaus, E. (2008) Isotopic evidence for omnivory among European cave bears: Late Pleistocene Ursus spelaeus from the Peştera cu Oase, Romania. Proceedings of the National Academy of Sciences USA (in press).

Source: EurekAlert!

Blog Carnival – Tangled Bank #95

The 95th installment of the Tangled Bank is now up for your perusal at Ouroboros. There’s a considerable selection of scientific writing on display, ranging from examinations of the future of scientific papers and ethics, through to the study of the brain. I particularly enjoyed Greg Laden’s review of a study that suggests an increased rate of human adaptive evolution. This study is one that has generated considerable comment in the blogosphere in recent weeks.

Red Sky at Night

A quick snippet from the latest edition of Current Archaeology:

“Our own record on pollution in the past has left a mark in an unexpected place: a team of scientists has been studying Turner’s paintings for evidence of man-made pollution in the 19th century and of the impact of major volcanic eruptions. Turner’s watercolours are especially helpful because he sketched the vivid sunsets that resulted from atmospheric dirt and dust with remarkable precision. By studying his work, scientists have identified the years 1813, 1831 and 1835 as periods when the skies were reddest as a result of pollution.”

Reference: Catling, C. 2007. Turner’s red skies. Current Archaeology 214: 8

Bear hunting altered genetics more than Ice Age isolation

It was not the isolation of the Ice Age that determined the genetic distribution of bears, as has long been thought. This is shown by an international research team led from Uppsala University in Sweden in the latest issue of Molecular Ecology. One possible interpretation is that the hunting of bears by humans and human land use have been crucial factors.

Twenty thousand years ago Europe was covered by ice down to Germany, and the climate in the rest of Europe was such that several species were confined to the southern regions, like the Iberian Peninsula and Italy. These regions were refuges, areas where species could survive during cold periods and then re-colonize central and northern Europe when it got warmer. But the brown bear was not limited to these regions, ­it could roam freely across major parts of southern and central Europe. The current study analysed mitochondria from bear remains. Some of the fossils are 20,000 years old. The analysis shows that the genetic pattern in these ancient brown bears differed from that of bears living today.

“Previously today’s genetic structure was interpreted as showing that the brown bear was isolated in southern Europe, just like many other species. But our study shows that this was not the case,” says Love Dalén, one of the Swedes participating in the study.

The new findings show instead that the brown bear survived in central Europe, even during the coldest period of the Ice Age. The scientists now believe that the genetic pattern found in today’s brown bears is the result of historical hunting and of human activities in the brown bear’s natural environment. A few thousand years ago, there were brown bears all over Europe, while today there are just a few remaining populations in Spain, Italy, the Balkans, and Scandinavia.

“It’s not strange that findings were interpreted differently in the past, with the brown bear extinct in most of its old area of inhabitation. We only had the remnant populations to work with,” says Anders Götherstam, who directed the study.

Source: EurekAlert!

390-million-year-old scorpion fossil — biggest bug known

The gigantic fossil claw of an 390 million-year-old sea scorpion, recently found in Germany, shows that ancient arthropods — spiders, insects, crabs and the like — were surprisingly larger than their modern-day counterparts.

“Imagine an eight-foot-long scorpion,” said O. Erik Tetlie, postdoctoral associate in the Department of Geology and Geophysics at Yale, and an author of the report online in Royal Society Biology Letters. “The claw itself is a foot-and-a-half long — indicating that these ancient arthropods were much larger than previous estimates — and certainly the largest seen to date.”

Colleague and co-author Markus Poschmann discovered the fossil claw from this ancient sea scorpion, Jaekelopterus rhenaniae, in a quarry near Prüm in Germany. This creature, which lived between 460 and 255 million years ago is of a group that have been known for some time to be among the largest extinct arthropods, based on both body fossils and trace fossils. According to the authors, it is believed that these extinct aquatic creatures are the ancestors of modern scorpions and spiders.

Tetlie said that geologists are debating the reasons for evolution of these giant arthropods, “While some believe they evolved with the higher levels of atmospheric oxygen that were present in the past, some say they evolved in a parallel ‘arms race’ with early armoured fish that were their likely prey.” he said.

Lead author Simon Braddy from the Department of Earth Sciences at the University of Bristol, UK said, “This is an amazing discovery. We have known for some time that the fossil record yields monster millipedes, super-sized scorpions, colossal cockroaches, and jumbo dragonflies, but we never realised, until now, just how big some of these ancient creepy-crawlies were.”

Source: EurekAlert!

Blog Carnival – Tangled Bank #93

Jim Lemire of From Archaea to Zeaxanthol is the host of the 93rd edition of the Tangled Bank, and an interesting edition it is too. Those contributions I found particularly intriguing included John at a DC Birding Blog’s discussion about what claws can tell us about bird evolution, and Coturnix’s description of the extreme dinosaur Nigersaurus. There’s plenty there for all though so go and read.

The earliest chocolate drink of the New World

The earliest known use of cacao –– the source of our modern day chocolate –– has been pushed back more than 500 years, to somewhere between 1400 and 1100 B.C.E., thanks to new chemical analyses of residues extracted from pottery excavated at an archaeological site at Puerto Escondido in Honduras. The new evidence also indicates that, long before the flavour of the cacao seed (or bean) became popular, it was the sweet pulp of the chocolate fruit, used in making a fermented (5% alcohol) beverage, which first drew attention to the plant in the Americas.

For more details, see the full release at the University of Pennsylvania Museum of Anthropology and Archaeology website.

‘Noah’s flood’ kick-started European farming

The flood believed to be behind the Noah’s Ark myth kick-started European agriculture, according to new research by the Universities of Exeter, UK and Wollongong, Australia. Published in the journal Quaternary Science Reviews, the research paper assesses the impact of the collapse of the North American (Laurentide) Ice Sheet, 8000 years ago. The results indicate a catastrophic rise in global sea level led to the flooding of the Black Sea and drove dramatic social change across Europe. The research team argues that, in the face of rising sea levels driven by contemporary climate change, we can learn important lessons from the past.

The collapse of the Laurentide Ice Sheet released a deluge of water that increased global sea levels by up to 1.4 metres and caused the largest North Atlantic freshwater pulse of the last 100,000 years. Before this time, a ridge across the Bosporus Strait dammed the Mediterranean and kept the Black Sea as a freshwater lake. With the rise in sea level, the Bosporus Strait was breached, flooding the Black Sea. This event is now widely believed to be behind the various folk myths that led to the biblical Noah’s Ark story. Archaeological records show that around this time there was a sudden expansion of farming and pottery production across Europe, marking the end of the Mesolithic hunter-gatherer era and the start of the Neolithic. The link between rising sea levels and such massive social change has previously been unclear.

The researchers created reconstructions of the Mediterranean and Black Sea shoreline before and after the rise in sea levels. They estimated that nearly 73,000 square km of land was lost to the sea over a period of 34 years. Based on our knowledge of historical population levels, this could have led to the displacement of 145,000 people. Archaeological evidence shows that communities in southeast Europe were already practising early farming techniques and pottery production before the Flood. With the catastrophic rise in water levels it appears they moved west, taking their culture into areas inhabited by hunter-gatherer communities.

Professor Chris Turney of the University of Exeter, lead author of the paper, said: “People living in what is now southeast Europe must have felt as though the whole world had flooded. This could well have been the origin of the Noah’s Ark story. Entire coastal communities must have been displaced, forcing people to migrate in their thousands. As these agricultural communities moved west, they would have taken farming with them across Europe. It was a revolutionary time.”

The rise in global sea levels 8000 years ago is in-line with current estimates for the end of the 21st century. Professor Chris Turney continued: “This research shows how rising sea levels can cause massive social change. 8,000 years on, are we any better placed to deal with rising sea levels” The latest estimates suggest that by AD 2050, millions of people will be displaced each year by rising sea levels. For those people living in coastal communities, the omen isn’t good.”

Source: EurekAlert!

‘Island Rule’ Refuted

A theory explaining the evolution of giant rodents, miniature elephants, and even miniature humans on islands has been called into questions by new research. The new study refutes the ‘island rule’ which says that in island environments small mammals such as rodents tend to evolve to be larger, and large mammals such as elephants tend to evolve to be smaller, with the original size of the species being the key determining factor in these changes.

The new research findings suggest that the tendency to either evolve larger or smaller on islands varies from one group of species to another, irrespective of original size. The research team, from Imperial College London, suspect instead that a number of external factors, including the physical environment of the particular island, the availability of prey, the presence of predators and the presence of competing species all play a role in determining the size evolution of island mammals.

Dr Shai Meiri from the NERC Centre for Population Biology at Imperial College London, lead author on the paper, explains: “If the island rule was correct, then most large mammals living on islands would be smaller than their continental relatives, and most small island mammals would be larger those living on continents. Our large dataset of mammal body sizes shows that this isn’t the case: there is evidence that most mammal groups show no tendency to consistently either grow larger or smaller, in contradiction to the island rule.”

Dr Meiri, who carried out the work with Professor Andy Purvis and Natalie Cooper from the College’s Department of Life Sciences, added: “The island rule suggests that the smallest mammals such as mice will exhibit the most evolutionary growth on islands, whilst the largest mammals like elephants will dwarf the most, with all mammals in between on a sliding-scale.

“Our analyses showed this isn’t the case, and the relationship between mammal size and evolutionary size change on islands is not that straightforward. Crucially, when we examined size change in light of the evolutionary relationship between different species, there was no connection between an evolution towards large size and greater degree of dwarfism on islands, or between evolution towards small size and island gigantism.”

The research team concluded that although there does appear to be a weak correlation between the size of a mammal and how its size then evolves in an island habitat, this reflects some groups’ specific tendencies towards gigantism or dwarfism, and not the general course of evolution. “The course of size evolution is dependent on a complex interplay of many other factors, that have led to the evolution of fascinating miniature and giant species of mammals on islands,” concludes Dr Meiri.

This research was published November 7, 2007 in the Proceedings of the Royal Society B: Biological Sciences.

Source: Science Daily

Blog Carnival – Tangled Bank #92

Paddy K is the host of the 92nd edition of the Tangled Bank and he has provided an interesting assortment of scientific bites, as well as some highly amusing hallowe’en costumes for his guests. I particularly enjoyed the Mad Hatter’s attempts to ‘play Whac-A-Mole With polio’ and Ed Yong’s explanation of ‘how India became the fastest continent’. All of the contributions are well worthy a read, however, so why not take a wander over to the Swedish Extravangaza and join in the party.