Carnivore has two different meanings. In ordinary language, it means an animal that only eats other animals, as contrasted with an herbivore (plant-eater) or omnivore (animal for whom both plants and animals are regular and important parts of the diet).
To a zoologist, carnivore usually means "a mammal belonging to the order carnivora." This includes cats and "cat-like" families such as mongooses and hyenas, and dogs and "dog-like" families such as bears, skunks, weasels, raccoons, and seals. Most members of the order carnivora actually are carnivores in the sense of being meat-eaters, but there are many carnivorous animals that do not belong to the order "carnivora."
There have been many studies to show that most carnivorous animals still possess digestive systems to eat a plant-only diet. This is considered by creationists to be strong evidence of life in the Garden of Eden before the Fall of Man. Many zoos to this day feed their lions and tigers leafy greens due to environmentalists and to protect them against chemicals that are added in meat produce to help preserve them. In the same way carnivorous pets such as cats, dogs, or even snakes can survive on a meat-free diet. In all these cases, nutritional supplements are required to supply traces of the few chemicals they cannot absorb from post-fall plants - setting a meat-free diet for a carnivorous animal should be done only with professional consultation.
A trick question for someone who knows biology is: "If a panda is a carnivore, then what is a koala?" Because a koala eats eucalyptus leaves, many people will fall into the trap and answer "herbivore", which is the wrong answer. The trick is that a panda does not eat meat. So, for a panda to be "a carnivore," the word must be being used in the sense of "order carnivora," and the right answer is "marsupial."
- Wile, Dr. Jay L. Exploring Creation Through General Science. Anderson: Apologia Educational Ministries, Inc. 2000