The Thousand Elil
The embleer hrair, or "stinking thousand", refer to the elil or predatory enemies of rabbits. These animals, many of which do have a strong odor, include the weasel, the fox, the dog, and the skunk. The mythical rabbit leader El-Ahrairah gets his name partly because he is the Prince with the Thousand Enemies. Throughout the story, the rabbits encounter dogs, a cat, humans, a skunk, a fox, rats, and various other predators.
The Running Rabbit
When the rabbits speak of another rabbit as having "stopped running", they mean that he or she is dead. A rabbit that can run, by definition, is alive and can defend himself or herself. A dead rabbit obviously cannot. Rabbits that do not run from danger because they are injured (like Hazel), or caught in a snare (like Bigwig), or frightened into an immobile condition known as tharn are regarded as being close to death.
Train as Messenger of Lord Frith
During Captain Holly's escape from Efrafa, he and his companions are being chased by Efrafa rabbits but are saved when they cross a train track. The pursuing rabbits are run over or driven away by the train, which is an object so far outside the rabbits' understanding that they describe it as a messenger from Lord Frith.
El-Ahrairah as Trickster
The recurring image of a dashing, clever rabbit king willing to take risks and outwit his enemies is beloved to the rabbits of Watership Down, who genuinely believe in him.
Humans as Destructive Forces
With very few exceptions, humans are presented as wasteful, destructive, mindless but powerful creatures. Their reasons for doing as they do are not obvious to the rabbits or comprehensible to them, but they mistrust things they see as signs of human activity, such as trees planted in straight rows. The humans who destroy the Sandleford Warren, and the human who appears in Fiver's vision, are dangerous and evil creatures that kill for no reason. This contrasts with the little girl who saves Hazel from her cat.