These creatures; referred to simply as "Otters" by the Human colonists, are an intelligent race of beings which inhabit the swamps of the planet Sunday. They are sapient (although seemingly devoid of technology), gregarious, amphibious herbivores and resemble an Earth otter with a bear-like face. They have webbed paws, long clawed digits and incisor teeth specialized for gnawing through wood, rather like beavers. Despite their mammalian appearance, they are oviparous. While they haven't been officially recognized as intelligent by the Humans, their language can be translated by the TARDIS' telepathic circuits.
- Wetworld, by Mark Michalowski (2007)