On Earth, some animals have become extremely rare due to factors such as habitat loss, hunting, and climate change. Below are some of the rarest animals in the world, listed in order of rarity.
1. Sumatran Orangutan
Quantity: Approximately 800
Habitat: Sumatra, Indonesia
Characteristics: Sumatran orangutans are the most endangered orangutan species, inhabiting tropical rainforests. Their numbers have declined dramatically due to deforestation and illegal hunting. They are known for their high intelligence and social skills, and are important maintainers of the ecosystem.

2. Javan Rhinoceros
Quantity: Approximately 76
Habitat: Java Island, Indonesia
Characteristics: The Javan rhinoceros is one of the rarest large land animals in the world, almost completely extinct. Its habitat is severely threatened by human activities, and conservation efforts urgently need to be strengthened.

3. Northern White Rhinoceros
Quantity: Only 2 left
Habitat: Reserves in Kenya
Characteristics: The northern white rhinoceros is nearly extinct; the two remaining individuals are both females, and scientists are working to save the species through artificial breeding techniques. Their main threats are poaching and habitat loss.

4. Alaotran Gentle Lemur (Omani Kitten)
Quantity: Approximately 250
Habitat: Madagascar
Characteristics: The Omani lemur is an extremely rare species, inhabiting only the swamps of Madagascar. Habitat destruction and hunting have put it at risk of extinction.

5. Gabonese Tree Frog
Quantity: Unknown, but extremely rare
Habitat: Gabon
Characteristics: The Gabonese tree frog is known for its vibrant colors and unique habitat habits. Due to habitat loss and environmental change, their numbers have declined dramatically.

6. Bald Eagle (Steller's Sea Eagle)
Quantity: Approximately 4,000
Habitat: Russian Far East
Characteristics: The bald eagle is the largest sea eagle in the world, inhabiting cold coastlines and near rivers. Habitat destruction and dwindling food sources threaten its habitat.

7. Lord Howe Island Woodhen
Quantity: Approximately 250
Habitat: Eden Island, Australia
Characteristics: The Eden Island Pigeon is an extremely rare bird species, endangered due to predators introduced by humans. Conservation efforts include habitat restoration and the introduction of conservation measures.

8. Hainan Gibbon
Quantity: Approximately 30
Habitat: Hainan Island, China
Characteristics: The Hainan black macaque is one of the rarest apes in the world, threatened by habitat loss and human activity. Conservation efforts are underway to save this endangered species.

9. Southern Blue Kite (Spoon-billed Sandpiper)
Quantity: Approximately 500
Habitat: Wetlands of Asia
Characteristics: The Southern Blue Kite is an extremely rare bird species, threatened by habitat loss and climate change. Conservation organizations are working to protect its migration routes and breeding grounds.
10. Ring-tailed Lemur (Madagascar)
Quantity: Approximately 2,000
Habitat: Madagascar
Characteristics: Although the ring-tailed lemur population in Madagascar is relatively large, they still face the risk of extinction due to habitat destruction. They are an important part of Madagascar's unique ecosystem.

Protecting these rare animals is not only about saving their lives, but also about maintaining the balance of the entire ecosystem. Every species is an important part of nature, and protecting their habitats and reducing the impact of human activities is our shared responsibility.