Love is a prevalent theme in this novel. It's all over the place. Characters are in love within the bounds of marriage and without marriage. Humans love other humans in the story, but humans also express a fair amount of love toward animals too. The reader is shown both emotional love and physical love, which brings up another theme.
Sexuality. I'll spare you the retelling of the book's steamy parts. But what the book does do a nice job of is walking the reader through the main character's (Jacob's) changing attitude toward sex and sexuality. He starts off as an insecure virgin, as shown by this quote:
"I am, as far as I can tell, the oldest male virgin on the face of the earth. Certainly no one else my age is willing to admit it. […] Not too long ago some of the guys on my football team paid a woman a quarter apiece to let them do it, one after the other, in the cattle barn. As much as I had hoped to leave my virginity behind at Cornell, I couldn't bring myself to take part. I simply couldn't do it."
He then becomes a sexually experienced man in his prime, and then the book finishes with Jacob as an old man reminiscing about "the good old days."
Davidee1 listed old age as a theme. I would agree with that. Many parts of the book show Jacob as really old. He can barely move, so he spends a lot of his time reminiscing about his exploits as a younger man. The reader can see that his mind and emotional being are still completely intact and in line with how he was as a younger man. Some readers might interpret that as encouraging about old age, but I don't think the book sells that attitude too well. To me, it reads more like a carpe diem attitude. Jacob lived life to the fullest, but also wishes that he could have done more. I think the old age theme tells readers that we are all going to get old, so make sure you pack in as much fun as you can while you are able.
"But there's nothing to be done about it. All I can do is put in time waiting for the inevitable, observing as the ghosts of my past rattle around my vacuous present. They crash and bang and make themselves at home, mostly because there's no competition. I've stopped fighting them."
There is no competition with those old ghosts of his past because Jacob is not physically able to live the kind of life that would enable him to create new memories powerful enough to compete with the old memories.
In addition to love, courage, and freedom/confinement discussed above, other themes in Water for Elephants include:
4. Suffering: Yes, suffering is part of humanity and sometimes unavoidable for people like Jacob who must defend the people they love. Physical torture is depicted when August beats Rosie in order to have her walk on cue. Marlena also falls victim to August's beatings. But suffering is not just related to direct physical torture by someone; it can come when we are denied what we want. Jacob suffers when he is prevented from protecting the ones he loves.
Physical suffering from bodily harm is depicted when Marlena hurts her feet on making an emergency landing. This brings severe suffering.
5. Men and Masculinity: For Jacob, being a man in Water for Elephants means owning what you love and defending it. Others like August understand being a man as possessing others and getting something from them. Both men show masculinity as they tend to reach for Marlena, and ironically no one gets her.
6. Old age: We all probably will, when old, desire to be youthful again. Jacob does. But old habits die hard, or so Jacob reveals as his desire for excitement and wonder remain part of the inner him. However, old age is to be "dreaded," since it has robbed Jacob of the drama and wonder of his youth.
Water for Elephants by Sara Gruen depicts a number of themes discussed below:
1. Love: In the story, love is shown among the characters themselves. But what's more, love also exists between humans and animals. Love is shown between Jacob and Rosie, and Jacob and Marlena. Although Jacob is married to Marlena out of love, he finds himself bound to Rosie. Therefore, love exists also outside marriage according to this book. Love between Jacob and Rosie is shown when they both make emotional and physical pledges to each other.
2. Courage: Water for Elephants shows that everyone has to face some situations courageously some day—whether it is admitting murder and getting away with it, facing people to tell them they are liars, or just walking out of your home at the age of 93 like Jacob does.
3. Freedom and confinement: Confinement is not just physical—it can be mental or emotional. We find that people like Blackie and Earl held Jacob physically, while Rose is emotionally confined to Jacob and vice versa. Those cases show some type of lack of freedom.
Rosie actually uses her boundary as a weapon, pulling the stake that's supposed to tie her down out of the ground and using it to kill August. Yikes. Are there other times in the book when confinement turns out to be dangerous?
And, a lot of people seem to misunderstand this, but the theme of a book is a statement about life or human nature that is true in the story and true in real life.