Came across this earlier, thought it was interesting.

"This list is about animals that were once thought to be mere legends, but were eventually confirmed to be real. Today, many of these "mythical beasts" are so well known that we couldn't imagine a zoo without them!"

http://listverse.com/2010/04/16/10-beasts-that-used-to-be-mythical/

Makes you think when you remember that Mountain Gorillas were only accepted as real a century ago. What else could be out there or down there.

It goes to show how far the human race has come in such a relatively short space of time.

There may well be animals deep in the see that haven't been discovered yet.

All interesting 

And on the other hand, animals may go extinct without us realizing.  For example, I heard it may have taken close to a hundred years to confirm that cougars are extinct.

Cougars are NOT extinct. There is a family of them (at least 3; a mated pair, plus an offspring) that live in the mountains to the west of me, and they're seen from time to time by residents and hunters. Unless they somehow died in the past 8 months, which I find implausible.

Thanks for the excellent report, Dave.  I certainly hope you are right.  There are a few theories out there  that they are not actually extinct.  It was such sad news on the radio some time back.

Eastern Cougar Officially Extinct

http://news.discovery.com/animals/eastern-cougar-extinct-110303.htm

Quote from discovery.com, "Only western cougars still live in large enough numbers to maintain breeding populations, and they live on wild lands in the western United States and Canada."

My related point was that being extinct may take a long time to confirm.

Ok, that makes sense. I didn't realize you were referring to eastern cougars, which haven't been seen for a decade or two, so far as I know. So in a way, we were both right.

I learned something about cougars from you guys on this thread, so thanks for that 

But It is sad to hear of any species threatened with extinction 

Extinction has always made me very sad. They will never be seen again. We need to sort this kind of thing out, it's what upsets me most about the human race I think.