A report compiled for Britain's largest national park has identified 23 species of mammals, birds, amphibians and fish that once thrived in Britain and have the potential to live here again.
Ecologists who wrote the report, which is still in draft form, claim that large carnivores such as wolves, brown bears and the Eurasian lynx can all have beneficial impacts on the environment and act as a huge draw for tourism.
Researchers claim it would require at least 250 brown bears and a similar number of wolves to maintain viable populations of the animals.
But the report warns that as a result such large species would be difficult to sustain in relatively small areas of land and can pose a threat to livestock unless carefully managed.
Proposals to reintroduce large carnivores into the wild have met with opposition from landowners and farmers while they have also sparked fears that the predators could pose a threat to humans.
The Cairngorms National Park report is due to be presented to the park's board later this year and will be used to help decide which species the park authorities will attempt to reintroduce into the Highlands.
Among the other species put forward as possible candidates in the report are large herbivores such as elk, typically found in Scandinavia, reindeer and the Eurasian beaver.
Dr David Hetherington, an ecologist with Cairngorms National Park Authority and an expert on species reintroduction, insisted that some of the species such as common cranes, lynx and beavers were stronger candidates than others.
He said: "We were trying to identify those animals we know or strongly suspect existed here in the past, which human activity had a major factor in their decline or eventual extinction in this country.
"One animal that could be considered in the relative short term for reintroduction to this part of Scotland, however, would be the common crane as it would have very little impact in terms of needing to be managed.
"Wolves are certainly viable but their introduction could create quite a few problems in the countryside. Out of all of the large carnivores we looked at, the Eurasian lynx is the best candidate and would have the best ecological impact.
"These are theoretical candidates for reintroduction, but the brown bear is not a species likely to be a realistic candidate for further consideration."
European brown bears currently survive in parts of Eastern Europe, such as the Romanian forests, Russia and in parts of Scandinavia. Small populations also exist in the French Pyrenees, Italian Alps and in the Austrian Alps after reintroduction projects in the 1990s.
They are thought to have died out in Britain shortly before the medieval period due to heavy deforestation and hunting by humans.
Bones and skulls have been found scattered in many parts of the Scottish Highlands while bears are often depicted on Pictish stones.
The omnivores typically dwell in forests, feeding on berries, grasses, honey, insects, fish, carrion and small mammals.
While its American cousin is known to kill an average of two people every year, there have only been three fatalities due to brown bears in Scandinavia in the past century.
The report states that while brown bears would be a very significant wildlife tourism attraction and icon, the Highlands would struggle to support enough bears to produce a viable population.
Wolves are also known to have been present in Britain at least until the early 18th century when they were eventually killed off by persecution by landowners and hunters.
The report claims that wolves, which are currently found in the US, Eastern Europe and parts of Scandinavia, could help to reduce grazing pressure on forestry by controlling deer numbers while also providing a significant tourism attraction.
The report also proposes introducing Western polecats, which were driven out of Britain by the late 19th century, and wild boar, which have been extinct in the UK for at least 300 years.
But it concludes that the Eurasian lynx, beaver and common crane are the most likely candidates for reintroduction due to successes elsewhere in Europe.
Lynx, which disappeared from the UK around 1,000 years ago, could be reintroduced using animals captured in continental Europe where there are now populations living in Germany, Switzerland, Poland, Slovakia and France following reintroductions.
The common, or Eurasian crane, is a large wetland bird thought to have become extinct in the 17th century.
There are already attempts to reintroduce the Eurasian beaver into the UK with a pilot scheme currently under way on the west coast of Scotland and there are plans to reintroduce the species in Wales.
Natural England conducted a feasibility study on the reintroduction of the beaver across the UK, finding that the animals could help to boost wildlife populations by creating new habitats and prevent flooding by slowing the flow of water with the dams they build around their burrows.
Areas that have been suggested as potential sites for beaver reintroduction include the Weald of Kent, the New Forest, Bodmin Moor and the Lake District. Landowners, however, claim beavers could destroy crops and damage woodland.
Species reintroduction has been a controversial subject in recent years and Natural England has faced intense criticism over proposals to reintroduce the white tailed sea eagle.
Ross Montague, director of the Scottish Countryside Alliance, a body who represent supporters of the countryside, said: "Conservation efforts, in the Cairngorms and throughout Scotland, should be focused on maintaining and enhancing the native species already present – not introducing alien species which may or may not have been present in the dim and distant past.
"We are especially concerned with proposals to introduce species which could have unknown impacts on our fragile biodiversity and already endangered species such as the Scottish wildcat."