Final answer:
Horses and rabbits are hind gut fermenters, having specialized digestive systems to ferment plant material in the cecum and colon, while dogs and cats are not.
Step-by-step explanation:
The species that are considered hind gut fermenters are horses and rabbits. Unlike ruminants like cows and goats that have multiple stomach chambers for fermentation and digestion, hind gut fermenters accomplish fermentation in the hind part of their digestive systems, such as the cecum and colon. Horses have a large cecum that allows for fermentation of fibrous plant material. Similarly, rabbits have an enlarged cecum for fermentation; they also digest their food twice, first producing soft feces called cecotrophes that they then re-ingest to further digest the food material. Dogs and cats, on the other hand, are not hind gut fermenters; they rely on a more simplified, monogastric system without significant fermentation in the hindgut.