The meta keywords tag is useless. Personally, I wouldn’t even bother to have it. Search engines do not use it as a ranking factor, and haven’t for years.
I’m talking about your <title> element, which is the most important part of the page for SEO and should contain your primary target keywords. It doesn’t really matter where you get the <title> element, using the long title field usually makes sense. The important thing is that it be targeted to keyword phrases that you might be able to rank for. For example, instead of just "African Elephant" you might use something like "African Elephant Facts and Information" which would be an easier phrase to rank for, and still includes the main phrase "African Elephant."
This is becoming a lecture on SEO -- but I love to lecture about SEO, so that’s OK as long as you’re listening
I was mostly kidding, you don’t have to link to me (although if you do, you can use any of my pictures for your site). My site is in my sig:
http://www.freenaturepictures.com. It’s somewhat similar to your site, except heavier on the pictures and lighter on text information, which is one of the strengths of your site. At the moment I’m #2 for "nature pictures" although I was #1 for years until Fabulous Nature took my spot -- I’m still working on figuring out how they did that! If you feel like linking to me that’s fine, but it’s not terribly important, I already have thousands of links.