Avian Digestive Adaptations
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
Birds lack teeth, instead using a crop to store food and a two-chambered stomach — the proventriculus for gastric juices, the gizzard for grinding.
Show
Some birds swallow grit that lodges in the gizzard to help grind food in place of teeth.
Watch for
The gizzard grinds food mechanically with swallowed grit — it secretes no digestive enzymes itself; the proventriculus supplies those.