What Is Bulk Feeding?

Bulk feeding is one of five feeding strategies used by animals to obtain food. Bulk feeding is exhibited by animals that eat pieces of other organisms or swallow them whole. In general, the intensity of the physical activities will be directly proportional to the size of the meal to be consumed. This is a lot different in people, where a dietitian will demand that a person chew their food well before swallowing. The other feeding strategies include filter feeding (employed by diverse marine organisms, from krill to the blue whale), deposit feeding (earthworms and other animals that filter or pick from soil), fluid feeding (hummingbirds, which feed on nectar, or spiders, which suck out the innards of insects), and phagocytosis (used by protozoa that engulf food particles). It's basically a diet that's specific to certain species.

Bulk feeding is one of the most common feeding strategies among animals, especially among macroscopic animals, with which we are most familiar. Many herbivores, carnivores, and omnivores employ bulk feeding. Except for a few cetaceans (whales and relatives) that employ filter feeding, almost all organisms over a few inches in size engage in bulk feeding, including humans. One marked difference is that humans chew and digest food in small portions and not in chunks. It is one of the most efficient forms of feeding, especially on land -- it involves going right to the source of food and taking a big bite out of it, then repeating until full. This is usually followed by a long time of rest and then another period of staying active until the need to feed surfaces again.

A non-bulk feeder would be organisms like millipedes, which are deposit feeders, and various detrivores on land and sea, which eat detritus instead of chunks of living or recently dead organisms. Some bulk feeders, such as cows, are specialized for consuming plants, and have large barrel-like stomachs to break down difficult-to-digest grass. Others, such as felines and canids, are specialized carnivores, evolved to hunt down living organisms, kill them, and consume the fresh kill. Among the most flexible of organisms, omnivores like humans, use both strategies.

Among the largest historical bulk feeders, the sauropods, huge dinosaurs that lived throughout the Mesozoic era, consumed tonnes of plant matter per day to sustain their massive bulk. One sauropod, Brachiosaurus, weighed between 30 and 60 tonnes. These animals had large stones in their bellies, called gastroliths, to crush plant matter and release its nutrients for further digestion.