I probably posted this sometime in the distant past, but I can’t resist putting it up again because it is one of the most extraordinary videos you will see (and it just popped up on Upworthy, which is proving to be a very worthy site).
Here’s the backstory:
National Geographic photographer Paul Nicklen shares the incredible story of his personal encounter with a predatory leopard seal in the frigid waters of the Antarctic. These photographs–and many more–appear in his book, Polar Obsession. Available at http://www.nationalgeographic.com/books.
PS: Does Nicklen have the most incredible life, or what?
You can see Nicklen’s TED Talk here.
The Earthist Chronicles 
I found the work of Paul Nicklen quite by accident as well, including the video posted above. I immediately ordered Polar Obsession and it is by far one of the greatest books I have ever owned. Remarkable work, truly outstanding images, specifically of the elusive and stunning Narwhal whale. His words are equally powerful and the insight expressed about his interaction with the wild is beautiful. I highly recommend this book.