This increases stride frequency. Briefly describe a specialized function performed by the crop serve in a particular bird or group of birds. The crop is primarily a storage area for food in most birds, holding food awaiting entry to the stomach near the center of gravity of the body. The size of the crop is dependent on the amount of food ingested at one time, and how slowly it is digested. Birds with a high protein or easily digestible diet tend to have smaller crops than plant or seed feeders.
Hoatzins use the crop as a fermentation chamber to digest cellulose using symbiotic microorganisms.
This reflects the fact that most propulsion in swimming fish comes from the tail, and there is little need for head movement independent of the body. In tetrapods, the pectoral girdle is loosely attached or attached by soft tissue only to the axial skeleton, while the pelvic girdle is firmly attached at the sacral region. In tetrapods, most force application to push against the substrate is produced by the hind limbs, and they need to be rigidly connected to the spine. The forelimbs are often used to absorb energy when landing, and a flexible connection prevents jarring of the head and brain. Because pinnate muscles have more muscle fibers in a given volume, they can produce a greater amount of force than a similar sized muscle with parallel fibers.