I have long been a fan of Brian Jacques's Redwall series, so I'm ashamed to admit how long it took me to get around to reading Richard Adams's classic Watership Down. To put it mildly, I was blown away. While I enjoy the swashbuckling adventures of the Redwall creatures, I've always found them to be too anthropomorphised. Adams, on the other hand, had obviously done extensive research into the characteristics and behaviour of wild rabbits. His main source was Robert Lockley's book The Private Life of the Rabbit (1964)
Adams's rabbits have their own culture, language, proverbs, poetry, and mythology. They have limitations and strengths that make them extremely compelling. I especially enjoyed the passages in which the rabbits are stretched to their limits - While Adams does anthropomorphise them, he does not give them human thought capacities. His approach is to incorporate zoological knowledge into his imaginative portrayal, which is incredibly engaging.
The epic tale includes many layers of allegory, including mythical elements, allusions to other literature (such as the Odyssey), gender roles, and themes of power. The legendary tales of El-ahrairah add dimension to the main plot line. He serves as a sort of Robin Hood character, as well as fueling many different origin-like myths for the rabbit culture.
Adams's detailed yet un-decorative prose is reminiscent of Tolkien. Unfortunately, like Tolkien, the numerous characters are sometimes difficult to keep track of and the plot can be confusing at times. It was a little difficult to get into at first, but an initial commitment will pay off - the world Adams creates is consistent, captivating, and thought-provoking.