To celebrate World Animal Day, we've introduced 12 exotic animals that were once extinct and are now on the road to recovery. The proboscis bat is one of the few bat species that feeds almost exclusively on nectar. In Mexico, these bats suck nectar from agave plants and inadvertently help tequila producers pollinate agave plants.
摄影：Joel Sartore，National Geographic Photo Ark
The black-footed ferret is the only stoat endemic to the North American continent. These slender rodents prey on them at night, feeding mainly on prairie marmots. They spend 90% of their time underground, usually inhabiting burrows stolen from prairie marmots.
The Vancouver Island marmot is Canada's most popular and endangered native species. These rodents, which are the size of cats, hibernate in burrows in the winter and spend most of the summer foraging for edible grasses and flowering plants.
Both male and female emerald parrots have brightly colored feathers, and males have slightly brighter feathers. These small birds usually fly in pairs or in small groups, but scientists have also seen flocks of up to 30 emerald parrots.
Guatemalan crocodiles, also known as Mexican crocodiles, were hunted for their crocodile skins, which can be made into purses, clothes and shoes. Today, these crocodiles are protected in their entire Central American habitat.
The Przewalski's wild horse is the last true wild horse. Przewalski's wild horses are not descendants of domesticated races, and humans have never successfully domesticated them.
Giant pandas are an endangered species, and animal activists have been working to change that. These plump bears rarely reproduce and give birth to only one cub at a time.
The American crane is 150 cm taller and is the tallest bird in North America. The bones of American cranes are hollow, so they are very light, usually no more than 7 kg.
Although the island grey fox is one of the smallest foxes on Earth, it is the largest terrestrial mammal in California's Channel Islands. The island grey fox is comparable in size to domestic cats, weighing between 1.8-2.3 kg.
The blue rock iguana is a larger lizard that has a longer lifespan and breeds more frequently. This critically endangered reptile can reach 1.5 meters in length and weigh 11 kilograms.
The Louisiana black bear is the official mammal of Louisiana, but its habitat extends all the way to Mississippi and eastern Texas. These bears have black fur, but some have a distinct white band on their chests.
In the animal kingdom, sea otters have the thickest hairs. Sea otters contain nearly 154,000 hairs per square centimeter of fur. Unlike other marine mammals, sea otters do not have blubber in their bodies. Thick hair allows sea otters to keep air in their fur, so they stay dry and warm in the icy waters of the Pacific Ocean.