In both ruminants and non-ruminants some additional fermentation occurs in the caecum. A number of the Carnivora are omnivores though, particularly the Bears, Badgers and Mongooses. The Baleen Whales, of course, feed on crustaceans - another group of arthropods. Most of the pinnipeds feed on fish or seabirds. For the larger carnivorous mammals, the commonest prey are other mammals and birds.
Hyenas are primarily scavengers on the already dead.
Lizards and snakes are preyed on by a few species particularly the Mongooses. Species that are happy to prey on venomous snakes are all resistant to some extent to the snake's venom. Thus, the European Hedgehog is 35-40 times more resistant to the venom of the common viper than other mammals. Within aquatic environments fish are the primary vertebrates. They are preferentially preyed on not only by seals and otters but also by at least 3 species of bats.