What is the purpose of lynx tips on a Maine Coon's ears?

Firstly, the tufts of hair sticking out of the top of a Maine Coon's ear flaps are named after the lynx wild cat as they have them in abundance. The tufts of hair on the lynx wild cat are believed to have a function but we don't know as yet what it is! Perhaps a communication tool via body language. They are likely to be functional to improve survival as almost everything that evolves is designed to improve survival.

Maine Coon lynx tips on the ears are purely decorative. Image: MikeB

But for the Maine Coon cat these impressive tufts of hair are decorative. They enhance the ear. They decorate the ear as if decorating a sofa with cushions 😎💓. Same thing.

There is a rules-based reason: the breed standards insist on them. I've quoted the CFA breed standard in the infographic on this page.

The standard allows for breeder discretion which is why you see large variations in the length and density of lynx tips depending on the breeder. The breeders create them over generations of selective breeding from foundation cats that have great lynx tips. They gradually refine them as if molding clay. 

The original Maine Coons from the 1900s did not have these prominent lynx tipped ears. They would have had ears like today's random bred (non-purebred) cats.

Lynx tips are one of the defining appearance features of this popular cat.

Of the wild cats, the caracal has the most impressive tufts of hair growing out of the tips of their ears. I guess the cat associations could have referred to this medium-sized wild cat rather than the lynx. If they had they would have been called 'caracal tips'. One person who kept a caracal as a pet says they are used for communication by the caracal.

I think the American cat associations chose the Canada lynx as the species as they much nearer to home, in Canada, whereas the caracal is found in South Africa, across swathes of Africa and in the Middle East.