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87-630: Giant tortoises are any of various large land tortoises Giant tortoise or giant tortoises may also refer to: Giant tortoise Giant tortoises are any of several species of various large land tortoises , which include a number of extinct species, as well as two extant species with multiple subspecies formerly common on the islands of the western Indian Ocean and on the Galápagos Islands . As of February 2024, two different species of giant tortoise are found on two remote groups of tropical islands: Aldabra Atoll and Fregate Island in

174-700: A broad trend of very gradual cooling known as Neoglaciation , which lasted from the end of the HCO to before the Industrial Revolution . From the 10th-14th century, the climate was similar to that of modern times during a period known as the Mediaeval Warm Period (MWP), also known as the Mediaeval Climatic Optimum (MCO). It was found that the warming that is taking place in current years is both more frequent and more spatially homogeneous than what

261-477: A cure for many ailments , including scurvy . On Mauritius, the giant tortoise disappeared from the main island by the end of the 17th century and the very last tortoises survived until the 1730s on the islets in the north. Around the late 1800s, large number of tortoise bones were discovered in the Mare aux Songes excavations. These resulted in the description of the two species of giant tortoise endemic to Mauritius,

348-414: A day resting. Their activity level is driven by ambient temperature and food availability. In the cool season, they are active at midday, sleeping in during the morning and afternoon. In the hot season, their active period is early morning and late afternoon, while midday finds them resting and trying to keep cool under the shade of a bush or half-submerged in muddy wallows. Tortoises breed primarily during

435-593: A larger effect on the mid-to-low latitudes and mid-to-high latitudes after ~5600 B.P. Human activity through land use changes already by the Mesolithic had major ecological impacts; it was an important influence on Holocene climatic changes, and is believed to be why the Holocene is an atypical interglacial that has not experienced significant cooling over its course. From the start of the Industrial Revolution onwards, large-scale anthropogenic greenhouse gas emissions caused

522-552: A marine transgression occurred in southeastern Africa; in the Lake Lungué basin, this sea level highstand occurred from 740 to 910 AD, or from 1,210 to 1,040 BP, as evidenced by the lake's connection to the Indian Ocean at this time. This transgression was followed by a period of transition that lasted until 590 BP, when the region experienced significant aridification and began to be extensively used by humans for livestock herding. In

609-643: A more sustainable sedentary lifestyle . This form of lifestyle change allowed humans to develop towns and villages in centralized locations, which gave rise to the world known today. It is believed that the domestication of plants and animals began in the early part of the Holocene in the tropical areas of the planet. Because these areas had warm, moist temperatures, the climate was perfect for effective farming. Culture development and human population change, specifically in South America, has also been linked to spikes in hydroclimate resulting in climate variability in

696-567: A much wetter climate from 11,400 to 11,100 BP due to intensification of the ISM. Over the Early Holocene, the region was very wet, but during the Middle Holocene from 6,200 to 3,900 BP, aridification occurred, with the subsequent Late Holocene being relatively arid as a whole. Coastal southwestern India experienced a stronger ISM from 9,690 to 7,560 BP, during the HCO. From 3,510 to 2,550 BP, during

783-596: A negative excursion in the δ O record lasting 400 years, is the most prominent climatic event occurring in the Holocene Epoch, and may have marked a resurgence of ice cover. It has been suggested that this event was caused by the final drainage of Lake Agassiz , which had been confined by the glaciers, disrupting the thermohaline circulation of the Atlantic . This disruption was the result of an ice dam over Hudson Bay collapsing sending cold lake Agassiz water into

870-497: A number of other, more accessible islands. During the Pleistocene , and mostly during the last 50,000 years, tortoises of the mainland of southern Asia († Megalochelys atlas ), North America († Hesperotestudo spp.) and South America ( Chelonoidis spp.), Indonesia , Madagascar († Aldabrachelys ) and even the island of Malta all became extinct. Giant tortoises († Titanochelon ) also inhabited mainland Europe until

957-467: A role. Drangajökull, Iceland's northernmost glacier, melted shortly after 9,200 BP. In Northern Germany , the Middle Holocene saw a drastic increase in the amount of raised bogs, most likely related to sea level rise. Although human activity affected geomorphology and landscape evolution in Northern Germany throughout the Holocene, it only became a dominant influence in the last four centuries. In

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1044-555: A ship's hold with tortoises was an easy way to stock up on food, a tradition that was continued by whalers in the centuries that followed. The tortoises also conveniently held water in their necks that could be used as drinking water. These buccaneers stocked giant tortoises not only because of their meat but because of these animals' ability to survive for six months to one year without food or water. Once buccaneers, whalers and fur sealers discovered that they could have fresh meat for their long voyages by storing live giant tortoises in

1131-504: A single genus (often referred to as Testudo or Geochelone ), but more recent studies have shown that giant tortoises represent several distinct lineages that are not closely related to one another. These lineages appear to have developed large size independently and, as a result, giant tortoises are polyphyletic . For example, the Aldabra Atoll ( Aldabrachelys ) giant tortoises are related to Malagasy tortoises ( Asterochelys ) while

1218-689: A tortoise subspecies once thought to have been extinct since 1906, the Fernandina giant tortoise, was discovered on its namesake island in the Galápagos. It is estimated that 20,000–25,000 wild tortoises live on the islands today. Galápagos tortoises are mainly herbivorous , feeding primarily on cactus pads, grasses, and native fruit but have been recorded eating baby birds in the case of the aldabran species. They drink large quantities of water when available that they can store in their bladders for long periods of time. There are two main types of shell among them,

1305-501: A variety of methods, with a view toward further verifying and refining the Blytt–Sernander sequence . This is a classification of climatic periods initially defined by plant remains in peat mosses . Though the method was once thought to be of little interest, based on C dating of peats that was inconsistent with the claimed chronozones, investigators have found a general correspondence across Eurasia and North America . The scheme

1392-429: Is known as island gigantism or insular gigantism. This may occur due to factors such as relaxed predation pressure, competitive release, or as an adaptation to increased environmental fluctuations on islands. However, giant tortoises are no longer considered to be classic examples of island gigantism, as similarly massive tortoises are now known to have once been widespread. Giant tortoises were formerly common (prior to

1479-553: Is the shell of an extinct giant tortoise found in a submerged sinkhole in Florida with a wooden spear piercing through it, carbon dated to 12,000 years ago. Today, only one of the subspecies of the Indian Ocean survives in the wild; the Aldabra giant tortoise (two more are claimed to exist in captive or re-released populations, but some genetic studies have cast doubt on the validity of these as separate species) and 10 extant species in

1566-693: The Fijian Archipelago . The identity of the Vanuatu meiolaniid has been controversial, however, with some studies concluding the remains actually belong to a giant tortoise, which are otherwise unknown from this region. Older (Early Miocene ) meiolaniids are also known from the St. Bathans fauna in New Zealand . Although often considered examples of island gigantism , prior to the arrival of Homo sapiens giant tortoises also occurred in non-island locales, as well as on

1653-658: The French Alps , geochemistry and lithium isotope signatures in lake sediments have suggested gradual soil formation from the Last Glacial Period to the Holocene climatic optimum , and this soil development was altered by the settlement of human societies. Early anthropogenic activities such as deforestation and agriculture reinforced soil erosion, which peaked in the Middle Ages at an unprecedented level, marking human forcing as

1740-625: The Galapagos giant tortoises are related to South American mainland tortoises, particularly the Chaco tortoise ( Chelonoidis chiliensis ). The recently extinct Mascarene giant tortoises ( Cylindraspis ) are thought to have belonged to their own branch of the tortoise family, being sister to all other modern tortoise genera aside from Manouria , Gopherus , and Testudo . Giant tortoises are classified into several distinct genera, including Aldabrachelys , Centrochelys (in part, often excluding

1827-525: The Galápagos . Giant tortoises are among the world's longest-living animals, with an average lifespan of 100 years or more. The Madagascar radiated tortoise Tu'i Malila was 188 at her death in Tonga in 1965. Harriet (initially thought to be one of the three Galápagos tortoises brought back to England from Charles Darwin 's Beagle voyage, but later shown to be from an island not even visited by Darwin)

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1914-603: The Intertropical Convergence Zone (ITCZ) produced increased monsoon rainfall over North Africa. The lush vegetation of the Sahara brought an increase in pastoralism . The AHP ended around 5,500 BP, after which the Sahara began to dry and become the desert it is today. A stronger East African Monsoon during the Middle Holocene increased precipitation in East Africa and raised lake levels. Around 800 AD, or 1,150 BP,

2001-717: The Kalahari Desert , Holocene climate was overall very stable and environmental change was of low amplitude. Relatively cool conditions have prevailed since 4,000 BP. In the Middle East, the Holocene brought a warmer and wetter climate, in contrast to the preceding cold, dry Younger Dryas . The Early Holocene saw the advent and spread of agriculture in the Fertile Crescent — sheep , goat , cattle , and later pig were domesticated, as well as cereals, like wheat and barley , and legumes —which would later disperse into much of

2088-522: The Mauritius saddle-backed ( Cylindraspis inepta ) and the Mauritius domed ( Cylindraspis triserrata ). Today, the only remains from these five species are a number of fossil bones and shells, a few drawings of live animals and one stuffed Rodrigues saddle-backed giant tortoise in France's National Museum of Natural History . Holocene The Holocene correlates with the last maximum axial tilt of

2175-717: The Mesolithic , Neolithic , and Bronze Age , are usually used. However, the time periods referenced by these terms vary with the emergence of those technologies in different parts of the world. Some scholars have argued that a third epoch of the Quaternary, the Anthropocene , has now begun. This term has been used to denote the present time-interval in which many geologically significant conditions and processes have been profoundly altered by human activities. The 'Anthropocene' (a term coined by Paul J. Crutzen and Eugene Stoermer in 2000)

2262-628: The North Atlantic ocean . Furthermore, studies show that the melting of Lake Agassiz led to sea-level rise which flooded the North American coastal landscape. The basal peat plant was then used to determine the resulting local sea-level rise of 0.20-0.56m in the Mississippi Delta . Subsequent research, however, suggested that the discharge was probably superimposed upon a longer episode of cooler climate lasting up to 600 years and observed that

2349-611: The Quaternary extinctions ) across the Cenozoic faunas of Eurasia , Africa and the Americas . Giant tortoises are notably absent from Australia and the South Pacific . However, extinct giant horned turtles ( Meiolaniidae ) likely filled a similar niche, with Late Pleistocene - Holocene meiolaniid species being known from Australia , New Caledonia , Lord Howe Island , Vanuatu , and

2436-571: The Seychelles and the Galápagos Islands in Ecuador . These tortoises can weigh as much as 417 kg (919 lb) and can grow to be 1.3 m (4 ft 3 in) long. Giant tortoises originally made their way to islands from the mainland via oceanic dispersal . Tortoises are aided in such dispersal by their ability to float with their heads up and to survive for up to six months without food or fresh water. Giant tortoises were once all placed in

2523-565: The Tien Shan , sedimentological evidence from Swan Lake suggests the period between 8,500 and 6,900 BP was relatively warm, with steppe meadow vegetation being predominant. An increase in Cyperaceae from 6,900 to 2,600 BP indicates cooling and humidification of the Tian Shan climate that was interrupted by a warm period between 5,500 and 4,500 BP. After 2,600 BP, an alpine steppe climate prevailed across

2610-965: The last glacial period . Local names for the last glacial period include the Wisconsinan in North America , the Weichselian in Europe, the Devensian in Britain, the Llanquihue in Chile and the Otiran in New Zealand. The Holocene can be subdivided into five time intervals, or chronozones , based on climatic fluctuations: Geologists working in different regions are studying sea levels, peat bogs, and ice-core samples, using

2697-535: The sixth mass extinction or Anthropocene extinction , is an ongoing extinction event of species during the present Holocene epoch (with the more recent time sometimes called Anthropocene) as a result of human activity . The included extinctions span numerous families of fungi , plants , and animals , including mammals , birds , reptiles , amphibians , fish and invertebrates . With widespread degradation of highly biodiverse habitats such as coral reefs and rainforests , as well as other areas,

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2784-662: The Early Pleistocene (2.0 Mya). The giant tortoises formerly of Africa died out somewhat earlier, during the Late Pliocene . While the timing of the disappearances of various extinct giant tortoise species seems to correlate with the arrival of humans, direct evidence for human involvement in these extinctions is usually lacking; however, such evidence has been obtained in the case of the distantly-related giant meiolaniid turtle Meiolania damelipi in Vanuatu . One interesting relic

2871-648: The Earth to warm. Likewise, climatic changes have induced substantial changes in human civilisation over the course of the Holocene. During the transition from the last glacial to the Holocene, the Huelmo–Mascardi Cold Reversal in the Southern Hemisphere began before the Younger Dryas, and the maximum warmth flowed south to north from 11,000 to 7,000 years ago. It appears that this was influenced by

2958-458: The Earth towards the Sun, and corresponds with the rapid proliferation, growth, and impacts of the human species worldwide, including all of its written history , technological revolutions , development of major civilizations , and overall significant transition towards urban living in the present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for

3045-527: The Galápagos. Colonizing the easternmost islands of Española and San Cristóbal first, they then dispersed throughout the archipelago , eventually establishing about 16 separate populations on 10 of the largest of the Galápagos Islands. Currently, there are only 10 subspecies of Galápagos giant tortoises left of the original 16 subspecies. During the 16th and 17th centuries, the Galápagos were frequented by buccaneers preying on Spanish treasure ships. Filling

3132-576: The Holocene Epoch. A 1,500-year cycle corresponding to the North Atlantic oceanic circulation may have had widespread global distribution in the Late Holocene. From 8,500 BP to 6,700 BP, North Atlantic climate oscillations were highly irregular and erratic because of perturbations from substantial ice discharge into the ocean from the collapsing Laurentide Ice Sheet. The Greenland ice core records indicate that climate changes became more regional and had

3219-474: The Holocene has shown significant variability despite ice core records from Greenland suggesting a more stable climate following the preceding ice age. Marine chemical fluxes during the Holocene were lower than during the Younger Dryas, but were still considerable enough to imply notable changes in the climate. The temporal and spatial extent of climate change during the Holocene is an area of considerable uncertainty, with radiative forcing recently proposed to be

3306-480: The Holocene, however, the domestication of plants and animals allowed humans to develop villages and towns in centralized locations. Archaeological data shows that between 10,000 and 7,000 BP rapid domestication of plants and animals took place in tropical and subtropical parts of Asia , Africa , and Central America . The development of farming allowed humans to transition away from hunter-gatherer nomadic cultures, which did not establish permanent settlements, to

3393-658: The International Union of Geological Sciences later formally confirmed, by a near unanimous vote, the rejection of the working group's Anthropocene Epoch proposal for inclusion in the Geologic Time Scale. The Holocene is a geologic epoch that follows directly after the Pleistocene . Continental motions due to plate tectonics are less than a kilometre over a span of only 10,000 years. However, ice melt caused world sea levels to rise about 35 m (115 ft) in

3480-437: The Late Holocene, the ISM became weaker, although this weakening was interrupted by an interval of unusually high ISM strength from 3,400 to 3,200 BP. Southwestern China experienced long-term warming during the Early Holocene up until ~7,000 BP. Northern China experienced an abrupt aridification event approximately 4,000 BP. From around 3,500 to 3,000 BP, northeastern China underwent a prolonged cooling, manifesting itself with

3567-476: The Late Holocene. Animal and plant life have not evolved much during the relatively short Holocene, but there have been major shifts in the richness and abundance of plants and animals. A number of large animals including mammoths and mastodons , saber-toothed cats like Smilodon and Homotherium , and giant sloths went extinct in the late Pleistocene and early Holocene. These extinctions can be mostly attributed to people. In America, it coincided with

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3654-454: The Middle Holocene was notable for its warmth, with rhythmic temperature fluctuations every 400-500 and 1,000 years. Before 7,500 BP, the Gulf of Thailand was exposed above sea level and was very arid. A marine transgression occurred from 7,500 to 6,200 BP amidst global warming. During the Middle Holocene, western North America was drier than present, with wetter winters and drier summers. After

3741-625: The Middle to Late Holocene, the coastline of the Levant and Persian Gulf receded, prompting a shift in human settlement patterns following this marine regression. Central Asia experienced glacial-like temperatures until about 8,000 BP, when the Laurentide Ice Sheet collapsed. In Xinjiang , long-term Holocene warming increased meltwater supply during summers, creating large lakes and oases at low altitudes and inducing enhanced moisture recycling. In

3828-520: The arrival of the Clovis people; this culture was known for " Clovis points " which were fashioned on spears for hunting animals. Shrubs, herbs, and mosses had also changed in relative abundance from the Pleistocene to Holocene, identified by permafrost core samples. Throughout the world, ecosystems in cooler climates that were previously regional have been isolated in higher altitude ecological "islands". The 8.2-ka event , an abrupt cold spell recorded as

3915-450: The disruption of Bronze Age civilisations in the region. Eastern and southern China, the monsoonal regions of China, were wetter than present in the Early and Middle Holocene. Lake Huguangyan's TOC, δ C wax , δ C org , δ N values suggest the period of peak moisture lasted from 9,200 to 1,800 BP and was attributable to a strong East Asian Summer Monsoon (EASM). Late Holocene cooling events in

4002-473: The early part of the Holocene and another 30 m in the later part of the Holocene. In addition, many areas above about 40 degrees north latitude had been depressed by the weight of the Pleistocene glaciers and rose as much as 180 m (590 ft) due to post-glacial rebound over the late Pleistocene and Holocene, and are still rising today. The sea-level rise and temporary land depression allowed temporary marine incursions into areas that are now far from

4089-427: The end of the last strong phase. Ice core measurements imply that the sea surface temperature (SST) gradient east of New Zealand, across the subtropical front (STF), was around 2 degrees Celsius during the HCO. This temperature gradient is significantly less than modern times, which is around 6 degrees Celsius. A study utilizing five SST proxies from 37°S to 60°S latitude confirmed that the strong temperature gradient

4176-601: The end of the thermal maximum of the HCO around 4,500 BP, the East Greenland Current underwent strengthening. A massive megadrought occurred from 2,800 to 1,850 BP in the Great Basin . Eastern North America underwent abrupt warming and humidification around 10,500 BP and then declined from 9,300 to 9,100 BP. The region has undergone a long term wettening since 5,500 BP occasionally interrupted by intervals of high aridity. A major cool event lasting from 5,500 to 4,700 BP

4263-593: The extant African spurred tortoise ( Centrochelys sulcata )), Chelonoidis (in part), † Cylindraspis (extinct c. 1840) , † Hesperotestudo (extinct c. 9,000 years Before Present ) , † Megalochelys , † Solitudo , and † Titanochelon . Both Megalochelys and Titanochelon reached sizes substantially greater than modern giant tortoises, with up to 2.4 m (7 ft 10 in) and 2 m (6 ft 7 in) shell lengths respectively. The phenomenon of animal species evolving in cache to unusually large size on islands (in comparison to continental relatives)

4350-527: The extent of the area affected was unclear. The beginning of the Holocene corresponds with the beginning of the Mesolithic age in most of Europe . In regions such as the Middle East and Anatolia , the term Epipaleolithic is preferred in place of Mesolithic, as they refer to approximately the same time period. Cultures in this period include Hamburgian , Federmesser , and the Natufian culture , during which

4437-418: The extinct genus Cylindraspis , comprising two species occurring on Mauritius, another two on Rodrigues, and one on Réunion. The tortoises were unique to these islands and had gained a number of special adaptations in the absence of ground predators . They differed from any other giant tortoise species because of their modified jaws, reduced scales on the legs and shells averaging just 1mm thick. The shells of

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4524-523: The former genus Dipsochelys refers to this adaptation . The closest living relative of the Galápagos giant tortoise ( Chelonoidis niger ) is the small Chaco tortoise from South America , although it is not a direct ancestor . Scientists believe the first tortoises arrived to the Galápagos 2–3 million years ago by drifting 600 miles from the South American coast on vegetation rafts or on their own. They were already large animals before arriving in

4611-522: The future evolution of living species, including approximately synchronous lithospheric evidence, or more recently hydrospheric and atmospheric evidence of the human impact. In July 2018, the International Union of Geological Sciences split the Holocene Epoch into three distinct ages based on the climate, Greenlandian (11,700 years ago to 8,200 years ago), Northgrippian (8,200 years ago to 4,200 years ago) and Meghalayan (4,200 years ago to

4698-497: The giant tortoises were open-ended; the name Cylindraspis actually means "cylinder-shaped". This was a specific adaptation in response to the lack of predators, where thick, heavily armored shells were no longer necessary. They belonged to a far more ancient lineage than the two extant giant tortoises, having diverged from all other tortoises during the Eocene , with divergence between the individual species far greater than that between

4785-463: The higher branches of trees. The males, although not much bigger than the females, weigh nearly 100 kg (220 lbs) more. They move slowly and have small, thick legs and round, almost flat feet that assist them in walking on sand. The Aldabra giant tortoise mainly inhabits grasslands and swamps on Aldabra Atoll's islands, which form a part of the Seychelles island chain in the Indian Ocean. In

4872-458: The holds of their ships, massive exploitation of the species began. Tortoises were also exploited for their oil, which was used to light the lamps of Quito. Two centuries of exploitation resulted in the loss of between 100,000 and 200,000 tortoises. Three subspecies have been extinct since the 19th century, and a fourth subspecies lost its last member, Lonesome George , in June 2012. In February 2019,

4959-409: The hot season from January to May; however, tortoises can be seen mating any month of the year. During the cool season (June to November), female tortoises migrate to nesting zones , which are generally located in low lands of the islands, to lay their eggs. A female can lay from 1–4 nests over a nesting season from June to December. She digs the hole with her hind feet, then lets the eggs drop down into

5046-491: The insular subspecies of the extant tortoises. The divergences between some Cylindraspis species are thought to be even older than the geologic history of the modern Mascarenes themselves, indicating that Cylindraspis originally inhabited several now-submerged island chains of the Mascarene Plateau before colonizing the modern Mascarene islands following their formation. Around the 16th century, with human arrival and

5133-506: The majority of their incubation will occur at the start of the hot season). After hatching, the young hatchlings remain in the nest for a few weeks before emerging out a small hole adjacent to the nest cap. Usually, the temperature of the nest influences on the sex of the hatchling. Warm temperatures would yield more females, while colder temperatures would yield more males. The Mascarene Islands of Mauritius , Réunion and Rodrigues once harboured five species of giant tortoise belonging to

5220-522: The mid-19th century. The LIA was the coldest interval of time of the past two millennia. Following the Industrial Revolution, warm decadal intervals became more common relative to before as a consequence of anthropogenic greenhouse gases, resulting in progressive global warming. In the late 20th century, anthropogenic forcing superseded variations in solar activity as the dominant driver of climate change, though solar activity has continued to play

5307-537: The mid-Holocene (8.2 - 4.2 k cal BP). Climate change on seasonality and available moisture also allowed for favorable agricultural conditions which promoted human development for Maya and Tiwanaku regions. In the Korean Peninsula , climatic changes fostered a population boom during the Middle Chulmun period from 5,500 to 5,000 BP, but contributed to a subsequent bust during the Late and Final Chulmun periods, from 5,000 to 4,000 BP and from 4,000 to 3,500 BP respectively. The Holocene extinction , otherwise referred to as

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5394-453: The most powerful factor affecting surface processes. The sedimentary record from Aitoliko Lagoon indicates that wet winters locally predominated from 210 to 160 BP, followed by dry winter dominance from 160 to 20 BP. North Africa, dominated by the Sahara Desert in the present, was instead a savanna dotted with large lakes during the Early and Middle Holocene, regionally known as the African Humid Period (AHP). The northward migration of

5481-416: The nest, and finally covers it again with her hind feet. The number of eggs ranges from 2 to 7 for saddle-backed tortoises to sometimes more than 20 to 25 eggs for domed tortoises. The eggs incubate from 110 to 175 days (incubation periods depend on the month the clutch was produced, with eggs laid early in the cool season requiring longer incubation periods than eggs laid at the end of the cool season, when

5568-459: The oldest inhabited places still existing on Earth were first settled, such as Tell es-Sultan (Jericho) in the Middle East . There is also evolving archeological evidence of proto-religion at locations such as Göbekli Tepe , as long ago as the 9th millennium BC . The preceding period of the Late Pleistocene had already brought advancements such as the bow and arrow , creating more efficient forms of hunting and replacing spear throwers . In

5655-539: The origin of cycles identified in the North Atlantic region. Climate cyclicity through the Holocene ( Bond events ) has been observed in or near marine settings and is strongly controlled by glacial input to the North Atlantic. Periodicities of ≈2500, ≈1500, and ≈1000 years are generally observed in the North Atlantic. At the same time spectral analyses of the continental record, which is remote from oceanic influence, reveal persistent periodicities of 1,000 and 500 years that may correspond to solar activity variations during

5742-686: The past, they shared the islands with multiple other giant tortoise species, but many of them were hunted to extinction in the 1700s and 1800s. Despite the fact that they are usually found in regions of dense low-lying vegetation, they have been known to wander into areas with more sparse vegetation and rocks when food is scarce. They can also be seen resting in shaded areas or shallow pools of water in order to cool themselves on hot days. Aldabra giant tortoises tend to spend their lives grazing , but will cover surprising distances in search of food and have also been observed on bare rock and thin soil. They can drink from very shallow pools through their nostrils ;

5829-444: The period exceeds any likely tectonic uplift of non-glacial origin. Post-glacial rebound in the Scandinavia region resulted in a shrinking Baltic Sea . The region continues to rise, still causing weak earthquakes across Northern Europe. An equivalent event in North America was the rebound of Hudson Bay , as it shrank from its larger, immediate post-glacial Tyrrell Sea phase, to its present boundaries. The climate throughout

5916-453: The present), as proposed by International Commission on Stratigraphy . The oldest age, the Greenlandian, was characterized by a warming following the preceding ice age. The Northgrippian Age is known for vast cooling due to a disruption in ocean circulations that was caused by the melting of glaciers. The most recent age of the Holocene is the present Meghalayan, which began with extreme drought that lasted around 200 years. The word Holocene

6003-407: The region were dominantly influenced by solar forcing, with many individual cold snaps linked to solar minima such as the Oort, Wolf , Spörer , and Maunder Minima . A notable cooling event in southeastern China occurred 3,200 BP. Strengthening of the winter monsoon occurred around 5,500, 4,000, and 2,500 BP. Monsoonal regions of China became more arid in the Late Holocene. In the Sea of Japan,

6090-480: The region. Sand dune evolution in the Bayanbulak Basin shows that the region was very dry from the Holocene's beginning until around 6,500 BP, when a wet interval began. In the Tibetan Plateau, the moisture optimum spanned from around 7,500 to 5,500 BP. The Tarim Basin records the onset of significant aridification around 3,000-2,000 BP. After 11,800 BP, and especially between 10,800 and 9,200 BP, Ladakh experienced tremendous moisture increase most likely related to

6177-515: The remote Aldabra Atoll , one of the Seychelles group of islands in the Indian Ocean It is the only living species in the genus Aldabrachelys . Two other species in the genus, Aldabrachelys abrupta , and Aldabrachelys grandidieri were formerly endemic to Madagascar, but became extinct after the arrival of people. Aldabra giant tortoises have large dome-shaped shells in order to protect their delicate bodies that lie beneath their shells. They also have long necks in order to eat leaves from

6264-628: The residual glacial ice remaining in the Northern Hemisphere until the later date. The first major phase of Holocene climate was the Preboreal . At the start of the Preboreal occurred the Preboreal Oscillation (PBO). The Holocene Climatic Optimum (HCO) was a period of warming throughout the globe but was not globally synchronous and uniform. Following the HCO, the global climate entered

6351-427: The saddle-backed shell and the domed shell. They both provide special adaption to different environments. The saddle-backed tortoises are the smallest Galápagos tortoises, but present a very long neck and pairs of legs. They live on arid zone and feed on cactus . The domed tortoises are bigger with shorter neck and legs, they are found in the more vegetated islands and feed on grass. They spend an average of 16 hours

6438-400: The sea. For example, marine fossils from the Holocene epoch have been found in locations such as Vermont and Michigan . Other than higher-latitude temporary marine incursions associated with glacial depression, Holocene fossils are found primarily in lakebed, floodplain , and cave deposits. Holocene marine deposits along low-latitude coastlines are rare because the rise in sea levels during

6525-721: The strengthening of the Indian Summer Monsoon (ISM). From 9,200 to 6,900 BP, relative aridity persisted in Ladakh. A second major humid phase occurred in Ladakh from 6,900 to 4,800 BP, after which the region was again arid. From 900 to 1,200 AD, during the MWP, the ISM was again strong as evidenced by low δ O values from the Ganga Plain. The sediments of Lonar Lake in Maharashtra record dry conditions around 11,400 BP that transitioned into

6612-399: The subsequent introduction of domestic animals, particularly pigs , the tortoises were hunted to extinction . The thin shells were of no protection against these new invaders; rats , cats and pigs devoured the eggs and young and thousands were collected alive for provisioning ships. Sometimes they were even hunted for their oil, which was very valuable around that time because it provided

6699-400: The term 'recent' as an incorrect way of referring to the Holocene, preferring the term 'modern' instead to describe current processes. It also observes that the term 'Flandrian' may be used as a synonym for Holocene, although it is becoming outdated. The International Commission on Stratigraphy, however, considers the Holocene to be an epoch following the Pleistocene and specifically following

6786-563: The world. This ' Neolithic Revolution ', likely influenced by Holocene climatic changes, included an increase in sedentism and population, eventually resulting in the world's first large-scale state societies in Mesopotamia and Egypt . During the Middle Holocene, the Intertropical Convergence Zone , which governs the incursion of monsoon precipitation through the Arabian Peninsula, shifted southwards, resulting in increased aridity. In

6873-417: Was around 2.1 metres above present and occurred about 5,800 to 5,000 BP. Sea levels at Rocas Atoll were likewise higher than present for much of the Late Holocene. The Northwest Australian Summer Monsoon was in a strong phase from 8,500 to 6,400 BP, from 5,000 to 4,000 BP (possibly until 3,000 BP), and from 1,300 to 900 BP, with weak phases in between and the current weak phase beginning around 900 BP after

6960-513: Was coeval with a major humidification before being terminated by a major drought and warming at the end of that interval. During the Early Holocene, relative sea level rose in the Bahia region, causing a landward expansion of mangroves. During the Late Holocene, the mangroves declined as sea level dropped and freshwater supply increased. In the Santa Catarina region, the maximum sea level highstand

7047-533: Was confined to the area immediately south of the STF, and is correlated with reduced westerly winds near New Zealand. Since 7,100 BP, New Zealand experienced 53 cyclones similar in magnitude to Cyclone Bola . Evidence from the Galápagos Islands shows that the El Niño–Southern Oscillation (ENSO) was significantly weaker during the Middle Holocene, but that the strength of ENSO became moderate to high over

7134-414: Was defined for Northern Europe , but the climate changes were claimed to occur more widely. The periods of the scheme include a few of the final pre-Holocene oscillations of the last glacial period and then classify climates of more recent prehistory . Paleontologists have not defined any faunal stages for the Holocene. If subdivision is necessary, periods of human technological development, such as

7221-460: Was experienced during the MWP. A warming of +1 degree Celsius occurs 5–40 times more frequently in modern years than during the MWP. The major forcing during the MWP was due to greater solar activity, which led to heterogeneity compared to the greenhouse gas forcing of modern years that leads to more homogeneous warming. This was followed by the Little Ice Age (LIA) from the 13th or 14th century to

7308-626: Was formed from two Ancient Greek words. Hólos ( ὅλος ) is the Greek word for "whole". "Cene" comes from the Greek word kainós ( καινός ), meaning "new". The concept is that this epoch is "entirely new". The suffix '-cene' is used for all the seven epochs of the Cenozoic Era. The International Commission on Stratigraphy has defined the Holocene as starting approximately 11,700 years before 2000 CE (11,650 cal years BP , or 9,700 BCE). The Subcommission on Quaternary Stratigraphy (SQS) regards

7395-550: Was never a formally defined geological unit. The Subcommission on Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS) had a working group to determine whether it should be. In May 2019, members of the working group voted in favour of recognizing the Anthropocene as formal chrono-stratigraphic unit, with stratigraphic signals around the mid-twentieth century CE as its base. The exact criteria

7482-927: Was reported by the Australia Zoo to be 176 years old when she died in 2006. On 23 March 2006, an Aldabra giant tortoise named Adwaita died at the Alipore Zoological Gardens in Kolkata . He was brought to the zoo in the 1870s from the estate of Lord Clive and is thought to have been around 255 years old when he died. Around the time of its discovery, they were caught for food in such large numbers that they became virtually extinct by 1900. Giant tortoises are now protected by strict conservation laws and are categorized as threatened species. Taxonomy of extant and extinct insular giant tortoise species follows Rhodin et al . (2021), unless otherwise noted. The Aldabra giant tortoise ( Aldabrachelys gigantea) lives on

7569-538: Was still to be determined, after which the recommendation also had to be approved by the working group's parent bodies (ultimately the International Union of Geological Sciences ). In March 2024, after 15 years of deliberation, the Anthropocene Epoch proposal of the working group was voted down by a wide margin by the SQS, owing largely to its shallow sedimentary record and extremely recent proposed start date. The ICS and

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