Due to its isolation, Madagascar's fauna is limited. Lemurs have little competition for food and only a few enemies. Yet two-thirds of the island's 30 lemur species are threatened, because less than 10 percent of Madagascar's original forests remain. At least 15 large species of lemur have gone extinct, including one giant lemur species that grew as large as gorillas.
One of the few nonhuman enemies of lemurs today are fossas, another victim of deforestation. Catlike predators with long tails, fossas hunt everything from lemurs and mice to wild pigs. Related to the mongoose, fossas are an endangered species. Only about 3,000 of the animals remain in Madagascar today.
Any zoo animal that suddenly found itself in the wild would be unlikely to survive. For starters, the animal would no longer receive veterinary care, which is one reason why zoo animals usually live longer than their wild relatives do.
Much of what wild animals need to know to survive is also learned behavior, which is another reason why it is notoriously difficult to reintroduce captive animals to the wild. Only a very small percentage of reintroduced species ultimately reestablish a sustainable population in the wild.
But Madagascar's landscape may not be a bad fit for lions, giraffes, zebras, and hippos. Much of the island's central landmass is covered by pseudosteppe, a habitat similar to the savannas and steppes found in the animals' native East Africa.
Hippos were numerous and diverse in Madagascar until a few centuries ago. But overhunting, habitat degradation, and the introduction of non-native animals, such as cows, contributed to the demise of hippos on the island.
"Plenty of hippo habitat remains, and establishing them would not be hard to do," Burney said. "But it might be unpopular with local people, as hippos are dangerous."
In Madagascar one character, a lion, must rediscover his predatory instincts to stay alive. That would be difficult for real-life lions to do on their own. Lion cubs learn to hunt from their mothers and members of their pride.
Whether introduced lions would know how to hunt or not, Madagascar's native fauna would not provide lions with the prey they need. But lions could hunt the domesticated cows and goats common on the island.
Zebras would have no natural predators to worry about.
The problem with giraffes, though, is that they consume up to a hundred pounds (45 kilograms) of forage per day, nipped mostly from the tender shoots at the tops of trees. If giraffes were introduced to Madagascar, they would put added pressure on the flora and ultimately the native fauna.
"The giraffes would destroy even more of the tree cover that other animals desperately depend on," said Blue, from the San Diego Zoo.
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