Giant tortoises, new research


This video is about giant tortoises and turtles.

From the BBC:

The truth about giant tortoises

They’re big but tortoises used to be much bigger, and while they may be slow on their feet their minds may be surprisingly quick

Henry Nicholls

Reputation: Giant tortoises live on islands. They can be aged by studying growth rings on their shells, which is how we know they are the longest lived vertebrate on record. Charles Darwin found they moved a whole lot faster than he’d imagined.

Reality: Giant tortoises are a recent evolutionary innovation and used to be everywhere, not just on islands. It’s impossible to age them accurately unless you know when they hatched. They are actually pretty slow. Darwin was probably chasing them.

The largest tortoises in the world are to be found on the Seychelles in the Indian Ocean and in the Galápagos in the Pacific. But this truth has given rise to the false belief – often found in textbooks – that their large size is a product of island life. It almost certainly isn’t.

This much is evident from a cursory inspection of the fossil record. A typical Galápagos tortoise has a carapace around 100 cm long. If this is the benchmark for “giant”, it is clear that giant tortoises were not restricted to small islands. They were everywhere.

In the southern USA and Central America, for instance, there was a monster of a tortoise known as the southeastern giant tortoise (Hesperotestudo crassiscutata) that only went extinct around 12,000 years ago.

In Queensland, Australia there used to be a beast that goes by the name of Owen’s giant horned ninja turtle (Ninjemys oweni). Before you ask, yes, it was named after the ninja turtles of teenage mutant fame.

Then there was the real mother of all giants, the Siwaliks giant tortoise (Megalochelys atlas), which was tramping around what is now the Punjab in India until a few million years ago. It was around twice the size of a Galápagos tortoise.

In addition, a 1999 genetic analysis of Galápagos tortoises suggests their ancestors were probably pretty large before they left mainland South America several million years ago.

In fact, it’s been argued that being big was a necessary pre-adaption for the successful colonization of remote oceanic islands. If it finds itself in the water, a giant tortoise will bob along tolerably well, its long neck ensuring it doesn’t take on too much water.

If there used to be so many giant tortoises, where are they all now? A recent study by the International Union for Conservation of Nature indicates that giant tortoises have suffered a far higher incidence of extinction than more modestly sized tortoises and turtles.

“These slow moving and non-threatening animals required minimal effort to find,” wrote Anders Rhodin, director of the Chelonian Research Foundation and his colleagues.

Worse, giant tortoises can survive without food or water for long periods. That meant they could be stored – alive – to provide fresh meat many months down the line.

“Tortoises were, essentially, the earliest pre-industrial version of ‘canned food’,” they suggest. Early hominins opened their shells with stone-tool “can-openers”.

It is only because humans came late to the Seychelles and the Galápagos that we can still marvel at these creatures today.

In these isolated spots, giant tortoises have become reptilian representatives, their extreme longevity casting them as a living link to a lost world. But how long do they live, really?

It is often said that you can age a tortoise by counting growth rings on its shell. Unfortunately, this is only reliable for the first year or two and is useless for aging an animal that is fully grown – which for giant tortoises is at the age of around 20.

The only reliable method of aging a tortoise is to record its year of birth. In a few instances where this has been done for giant tortoises, it is clear they can live for 150 years or more.

Giant tortoises are not known for their speed. When in the Galápagos in 1835, Charles Darwin found that they moved faster than he’d imagined.

“One large one, I found by pacing, walked at the rate of 60 yards in 10 minutes, or 360 in the hour,” he wrote in his Zoology Notes. “At this pace, the animal would go four miles [6.4 km] in the day & have a short time to rest.”

More recently, researchers have been using tracking devices to record movements of Galápagos tortoises in more detail. It turns out they are not nearly so lively, most of the time making small movements around a relatively small patch.

“Our tortoises don’t usually move more than absolute max of 2 km per day,” says Stephen Blake, coordinator of the Galápagos Tortoise Movement Ecology Programme. “Darwin was probably chasing them.”

They might be slow, but they are also probably smarter than most people imagine.

Research on the South American red-footed tortoise (a not-too-distant relative of the giant tortoises in the Galápagos) shows they use landmarks to create cognitive maps of their surroundings. They can also follow the gaze of another tortoise and learn from the behaviour of others. It seems likely that giant tortoises are capable of similar cognitive feats.

Beautiful new crayfish species discovery in Indonesia


Cherax pulcher, newly discovered crayfish

From Laughing Squid:

Cherax (Astaconephrops) pulcher’, A Newly Described Species of Brightly Colored Crayfish Found in Indonesia

by Glen Tickle at 12:43 pm on May 21, 2015

Cherax (Astaconephrops) pulcher is a newly described species of brightly colored crayfish found in Indonesia. The paper describing the species was published by Christian Lukhaup in the journal ZooKeys on May 4, 2015, but Lukhaup had seen the animal ten years ago in a photograph, and it has been sold in pet shops in Japan and Europe.

The bright blue, pink, and purple colors seen particularly in the males of the species along with spots on the animals’ shells make them look not unlike images of distant galaxies and gas clouds captured by the Hubble Space Telescope, or as Elahe Izadi of The Washington Post described them, “a Lisa Frank creation.”

Dutch marsh harrier, all the way to Ghana and back


This video, from Spain, shows a female marsh harrier, a red kite and a raven quarreling about food.

Translated from the Dutch ornithologists of Werkgroep Grauwe Kiekendief:

Thursday, May 21, 2015

A newcomer to the GPS logger research is marsh harrier “Roelof”, an adult male provided last summer with a GPS logger. Roelof returned this spring to East Groningen, with a logger packed with GPS positions. He turned out to have had a highly remarkable journey! …

Roelof returned on April 15, 2015 in East Groningen, where he presented himself at the local antenna network where we can remotely read stored GPS data. …

In the autumn of 2014 Roelof flew via Spain to his first wintering area in Senegal, where he arrived on 27 September. This route falls exactly within the narrow migration flyway which is usual for marsh harriers. Christiane Trierweiler et al. described that harriers do not remain all winter in a single area, but during the winter they move to southern areas as the northern areas get dry. These are mostly trips of several hundred kilometers.

Roelof left his first wintering area on November 10 to land about 500 kilometers to the south in Guinea. To our surprise Roelof did not stay there until the end of the winter, but he left the area on January 26 to fly 1,700 kilometers along the West African south coast, eventually ending up all the way in Ghana! Ghana is really far away for a Dutch marsh harrier, outside the ‘normal’ wintering area.

On the shores of Lake Volta

In Ghana Roelof stayed around the shores of Lake Volta. This huge lake is probably a good wintering place for marsh harriers and the question is how he ever ‘found’ this place. Did he come here in his youth by chance, making the place by now a fixed point in his annual schedule? Or perhaps Roelof has eastern genes telling him that in winter this is the place to be? Monitoring young harriers will be the key to answering this kind of exciting questions.

Roelof left the Volta Lake on February 28, keeping a northwesterly course. Aided by a firm tailwind he was ‘blown’ across the Sahara until he reached the ocean coast in the Western Sahara. From there he continued his journey towards the northeast, where he made two short stops in Morocco (as befits a marsh harrier). From Morocco, he flew straight back to exactly the same reed bed in eastern Groningen …

This photo by Ben Koks shows marsh harrier Roelof, on the left, and his female partner. On Roelof’s back, one can see his GPS logger.

Yellow-crowned wagtail on daffodil, video


This video shows a yellow-crowned wagtail on a daffodil in the Netherlands.

According to some, yellow-crowned wagtails are a subspecies of the western yellow wagtail. Others consider them a separate species.

They nest in Britain and near the English Channel coast. Less than 80 couples nest in the Netherlands.

Peter van Duijn made this video.

3.3-million-year-old stone tools discovery in Kenya


This video says about itself:

3.3-Million-Year-Old Stone Tools Found in Kenya

30 April 2015

Archaeologists find stone tools used by early human ancestors in Kenya that predate the oldest known tools found in Ethiopia by some 700,000 years.

From daily The Guardian in Britain:

Stone tool discovery pushes back dawn of culture by 700,000 years

Finding overturns idea that tool-making ability was unique to our own ancestors and is hailed as a “new beginning to the known archaeological record”

Hannah Devlin, science correspondent

Wednesday 20 May 2015 18.00 BST

The oldest known stone tools, dating to long before the emergence of modern humans, have been discovered in Africa.

The roughly-hewn stones, which are around 3.3 million years old, have been hailed by scientists as a “new beginning to the known archaeological record” and push back the dawn of culture by 700,000 years.

The discovery overturns the mainstream view that the ability to make stone tools was unique to our own ancestors and that it was one of a handful of traits that made early humans so special.

The new artefacts, found in Kenya’s Turkana basin, suggest that a variety [of] ancient apes were making similar advances in parallel across the African continent.

“It just rewrites the book on a lot of things that we thought were true,” said Chris Lepre, a geologist at the Lamont-Doherty Earth Observatory and Rutgers University, who precisely dated the tools.

The Homo genus, from which modern humans descend, only emerged around 2.5 million years ago, when forests gave way to open grassland environments in Africa. Until now, it was widely assumed that environmental changes around this time triggered the shift towards a bipedal hunter-gatherer life style.

Jason Lewis, of Stony Brook University in New York and a co-author, said: “The idea was that our lineage alone took the cognitive leap of hitting stones together to strike off sharp flakes and that this was the foundation of our evolutionary success. This discovery challenges the idea that the main characters that make us human, such as making stone tools, eating more meat, maybe using language, all evolved at once in a punctuated way, near the origins of the genus Homo.”

The question of what, or whom, might have made the tools remains a mystery, but fossils from around the same period found at the site provide some clues.

The skull of a 3.3-million-year-old hominin, Kenyanthropus platytops [sic; K. platyops] , was found in 1999 about a kilometre from the tool site and a skull fragment and tooth from the same species were found just a few hundred metres away.

Other species from the same era include Australopithecus afarensis, which the famous Lucy fossil belongs to.

Professor Fred Spoor, a palaeontologist at University College London and part of the team that discovered K. platytops [sic; platyops], said the tools were “a very important find”. “Until now the thinking’s been that if you want to be part of this special club ‘Homo’, you need to be a tool-maker,” he said. “The period before three million years ago was seen as a rather boring period of evolution, but now we know there was stuff happening.”

Until now, hominins such as Australopithecus, from the earlier time period have been caricatured as “upright, bipedal chimpanzees that were just grazing the landscape with not much else going on,” he added.

To the untrained eye, the tools look unremarkable – barely distinguishable from ordinary rocks. But to scientists familiar with early humans, the hallmarks of tool-making were obvious. “I could immediately see the scars and features characteristic of a knapped stone,” said Sonia Harmand, of Stony Brook, who made the discovery.

Professor Spoor and others who have examined the collection of tools have been impressed by the quality of the evidence.

“This is a momentous and well-researched discovery,” said paleoanthropologist Bernard Wood of George Washington University, who was not involved in the study. “I have seen some of these artefacts in the flesh, and I am convinced they were fashioned deliberately.”

The collection of several dozen tools appears to have been made by two different techniques. In one case, a core stone was held on an anvil and hit from above with a hammer stone to chip off sharp flakes, which the scientists believe could have been used to slice meat and plants. Other stones appear to have been held in two hands and struck against the anvil, again producing slices of stone.

Although the end results appear primitive, they demonstrate a degree of mental sophistication that is unexpected for such early hominins. Modern chimpanzees use natural stones as “tools” to crack nuts, for instance, but they stop short of actively fashioning their own tools.

The researchers relied on a layer of volcanic ash below the tools, which matched ash elsewhere that had been dated to 3.3 million years ago, to set a “floor” on the site’s age. The date was then refined by analysing magnetic minerals at the site, which contain a record of the Earth’s periodically switching magnetic field.

The findings are published today in the journal Nature.

See also here.

Curlew freed from fishing line


Removing the fishing line from the curlew, photo by NIOZ

Translated from Ecomare museum on Texel island in the Netherlands:

Curlew freed from fishing line – 18-05-15

A broken fishing line can create problems for a long time in nature. A curlew experienced that firsthand. The bird got one of its legs caught in such a loose end. The foot of the animal was already fully grown around it, indicating that it had already happened a while ago. Scientists from the NIOZ Royal Dutch Institute for Exploration of the Sea happened to see the curlew during their regular bird research on the uninhabited Wadden Island Griend. They managed to remove the line.