Figure 20.15 Undigested energy. (a) Owls such as this barn owl (Tyto alba) consume small rodents but they do not digest the hair and bones. (b) Instead owls regurgitate a pellet that contains these indigestible materials. Consumers that eat large amounts of indigestible materials have low assimilation efficiencies.
Photos by (a) Frederic Desmette/Biosphoto and (b) Philippe Clement/naturepl.com.