The woolly mammoth became extinct as a result of crippling bone disease that left them unable to fend off predators, according to startling new evidence from Russia. It was previously thought that the hairy beast simply died out from post-Ice Age climate change and being hunted to extinction by early man. But now a new theory is set to re-write the history books after the examination of more than 23,500 mammoth bones found them riddled with osteoporosis and lacking in calcium. Dr Leshchinsky, the head of the laboratory of Mesozoic and Cenozoic continental eco-systems, said: 'In some collections that we examined almost 100 per cent of the bones (pictured) had signs of osteoporosis' The major mineral deficiency - which came from the impact of rising temperatures on soil and water - resulted in them breaking their limbs and spines, and left them unable to walk. In turn it meant the giant animal, which stood 10ft (three metres) high, eventually collapsed to the ground and could not forage for food, or flee hunters. According to the Siberian Times, the new evidence was uncovered by Dr Sergey Leshchinsky, from Tomsk State University. He spent a decade analysing bone and teeth samples from mammoths that roamed western Europe and Russia between 10,000 and 30,000 years ago. Until now it was thought that the woolly mammoth simply died out from post-Ice Age climate change and being hunted to extinction by early man (analysis of bones at mammoth 'graveyard' pictured) One mammoth graveyard where many bones have been found is in Lugovskoe, Russia . Shown is a young mammoth jaw riddled with bone disease. According to the Siberian Times , the new evidence was uncovered by Dr Sergey Leshchinsky, from Tomsk State University . The deficiency in calcium - which came from the impact of rising temperatures on soil and water - resulted in mammoths breaking their bones (example pictured) limbs and spines, leaving them unable to walk . Since the 1700s scientists have debated what caused the demise of mammoths. All but a few isolated island populations disappeared between 20,000 and 10,000 years ago. One popular theory, bolstered by this study, is that Ice Age people hunted most of the mammoths out of existence. However, some experts argue that global warming helped make the giant creatures extinct between 20,000 and 25,000 years ago. Other researchers argue that an impact of extraterritorial objects in North America 13,000 years ago, led to rapid climate change, eventually wiping out the mammoths. Today, it's thought that a combination of factors led to extinction. But now a new theory - osteoperosis - might need to be added to the list. Dr Leshchinsky, the head of the laboratory of Mesozoic and Cenozoic continental eco-systems, said: 'In some collections that we examined, almost 100 per cent of the bones had signs of osteoporosis. 'Obviously, this led to a high traumatism among animals, such as sprains and fractures because of the smallest loads. 'Mammoths with damaged limbs or spines could not find food in sufficient quantities and lost the ability to follow the herd. 'Those who lagged behind the herd quickly became the prey of predators.' Roughly the same size as a modern African elephant, the woolly mammoth is widely thought to have become extinct as a direct result of climate change. Most experts say warming temperatures - twinned with rising sea levels - following the last Ice Age all but wiped out their traditional habitats about 20,000 years ago. However, others say they lived long past this era and were finally hunted to death by early humans, with remains found in the Russian Arctic showing they existed just 3,700 years ago. Now the scientific world will be excited by the emerging evidence that bone disease, and a chronic lack of calcium, could instead be to blame. Shown left and right are mammoth statues in Khanty-Mansiysk. The research, if proven true, would provide a somewhat unusual explanation for how woolly mammoths died out . Experts spent a decade analysing bone and teeth samples from mammoths ('graveyard' pictured)  that roamed western Europe and Russia between 10,000 and 30,000 years ago . Dr Leshchinsky, who wrote about his findings in the Archaeological and Anthropological Sciences journal, added: 'The articular surfaces of the limb bones in some specimens were not just damaged, they were mutilated with disease. 'The most typical signs were osteoporosis, osteofibrosis, osteomalacia, osteolysis, cartilage atrophy and fractures resulting in the formation of false joints, ulcers and friction grooves.' The palaeontologist said that in his opinion the cause of the deaths was a metabolic disorder caused by mineral starvation. It is thought that mammoths did try to make up for their calcium shortfall by eating clay on the waterfronts or in mud baths, but it was not in sufficient quantities to strengthen bones. Often dubbed the 'old person's disease' in humans osteoporosis is a condition that weakens bones and makes them fragile and more likely to break. It affects about three million people in the UK and one in 10 receives hospital treatment for fractures from falling down.
Mammoth bones found in Russia suggest new theory for their demise.
A major mineral deficiency was found in the 23,500-year-old bones.
Suggest mammoths may have been riddled with osteoporosis.
Animals would have eventually collapsed to the ground under own weight.