|Conservation status||Least concern|
The hoatzin (Opisthocomus hoatzin) is a South American bird whose chief characteristic is a pair of claws on each wing when young. The development of this feature cannot be explained by the Theory of Evolution, as it would represent an inexplicable step backwards in the evolutionary path.
The hoatzin (pronounced "wat-sin") is just over 26 inches long and weighs about 2.5 pounds. It is colored brown above, and yellow below. Bright red eyes are surrounded by bare blue facial skin, and its small head is topped by a loose crest of feathers. It has a small callus on its chest, which acts as a "tripod" for the bird when its crop is full from a heavy meal.
It feeds on swamp vegetation, grinding it up in its crop; the hoatzin has a digestive tract which function much like a cow's, a trait found in no other bird. The smell caused by its unique method of feeding has bestowed on it the name "stinkbird".
Two to five eggs are laid in nests overlooking swamp water, and both parents rear the young, feeding them regurgitated vegetable matter from their crops. The young are born with claws on their wings, enabling them to use all four limbs to clamber up back to the nest should they drop into the water.