Here's why:

* Adaptability: Ferns are incredibly adaptable plants. They can thrive in a wide range of environments, from shady forests to rocky cliffs.

* Moisture: While ferns prefer moist environments, they can tolerate drier conditions on mountains, especially in shaded areas or near streams.

* Spores: Ferns reproduce using spores, which are very light and can be easily dispersed by wind. This allows them to colonize new areas, including mountainous ones.

Examples of ferns that live on mountains:

* Lady Fern: Found in mountainous regions across North America.

* Bracken Fern: Common in mountainous areas worldwide.

* Polypody Fern: Often grows on rocky cliffs and ledges in mountains.

While ferns can thrive on mountains, their specific species and abundance will vary depending on altitude, climate, and available habitat.