1. They are solitary and secretive. Leopards are typically solitary animals, except when breeding. They also tend to be secretive and avoid contact with humans.
2. They are nocturnal. Leopards are most active at night, when it is more difficult for humans to see them.
3. They are well-camouflaged. Leopards have a spotted coat that helps them blend in with their surroundings.
4. They have a large range. Leopards are found in a wide range of habitats, from forests to grasslands to deserts. This makes it difficult for researchers to track them down.
Despite all of these challenges, researchers have been able to learn a great deal about leopards by using camera traps, GPS tracking, and other techniques.