On animals:

I am more inclined to say that animals are animals and are therefore called animals and humans are called humans because they are different from animals. Animals don't build aeroplanes and ships, they don't forge jewellery and they don't have objects of art to admire for their beauty or to be shocked by, they don't write books, etc. - I find it quite funny to compare yourself to an animal, for example, in a humorous context, but I wouldn't do it so much in a serious way, because everything we interpret into an animal is ultimately human thinking and feeling. That said, I have great respect for people who can deal with animals and are not afraid of large animals on land or in the water.

I have meanwhile moved away from saying that a human being is also an animal, for example because humans have a sexual and reproductive urge. They have it, but it doesn't make them any less human and no more animal, in my opinion. Unlike animals, humans can control their urges if they really want to. I don't think animals do this knowingly and willingly, they may do it instinctively or because food/water is scarce or other danger is imminent. I don't know that, but I think it's a safe assumption.

This is something I often think about.

I'd love to read your thoughts on this.

As far as the saying is aimed at venturing into the lion's den to undergo a challenge, I would agree. Then it's a metaphor, isn't it? Literally speaking, I would never approach a lion unless I had been around big cats for many years or from an early age and had therefore learnt to judge them well.