Incidentally, an elephant was used in their first big Hadoop book (and I would find it hard to believe that was coincidence): https://www.oreilly.com/library/view/hadoop-the-definitive/9.... There's a Hadoop-the-elephant logo that's trademarked by Apache, but elephant puns and even other drawings of yellow elephants abound in that community, and I'm not sure that's the kind of thing that trademark law could be enforced against even if the ASF wanted to.