He is clinging on for dear life.

I think i am clinging onto the last thread of hope.

Yes, it can be (clinging vines).
The word clinging is the present participle of the verb "to cling." It can be a verb form, an adjective, or a noun (gerund).

When a kangaroo is born, is is about the size of a bean. All it can do is crawl by instinct into the pouch, clinging with its tiny claws to its mother's fur. It then needs several more months inside the mother's pouch to complete its development.

Woodpeckers are clinging birds as well as sapsuckers and flickers :)

Adhesion is the clinging of one substance to another