Rabbits, hares and pikas are lagomorphs, placental mammals that belong to the order Lagomorpha.
Like rodents, lagomorphs have teeth that continually grow. They must constantly gnaw at things to keep their teeth from becoming too long.
Lagomorphs are herbivorous (eat plants). A lagomorph's diet mostly consists of grass.
Many other animals eat lagomorphs, so lagomorphs have evolved to have features that help them to avoid predators. Lagomorphs can run very quickly.
To help them detect when a predator is nearby, they have big ears. Their eyes are set high on their heads, which give them a wide field of vision.
Lagomorphs also have very flexible necks that allow them to rotate their heads at a wide angle, increasing their field of vision even further.
In addition, lagomorphs reproduce very quickly. This helps to compensate for the number of individuals that are eaten.
Lagomorphs mostly eat grass.
A lagomorph has bacteria in its cecum, a large sack between its small and large intestines. These bacteria help the lagomorph to digest cellulose.
When food is digested in the cecum, some of the nutrients that are produced are absorbed into the blood stream.
However, some nutrients cannot be absorbed. These are passed out of the lagomorph's anus in the form of cecal pellets, also known as cecotropes or night feces.
The lagomorph eats the cecal pellets. They are then redigested in a special section of the stomach.
This process allows the lagomorph to get all the nutrients it needs to survive.
In comparison, ruminants obtain nutrients from grass by regurgitating it after it is partially digested and then redigesting the regurgitated grass, which is known as cud.