These strange and quirky birds don’t look like cows- but they sure eat and supposedly smell like ‘em. As a folivore, the Hoatzin (Opisthocomus hoazin) can strip trees in their native land, northern South America, bare and, as a byproduct, reek of manure or sweet smelling hay. This has given them the title of ‘stink bird.’
But their diet of solely leaves, fruit and flowers has led to a digestive system unique to this species. They have a very large crop, or gizzard, which contains anaerobic bacteria to secret enzymes, grinding up all the cellulose that comes from this highly fibrous diet. The gizzard can account for up to a third of the hoatzin’s body weight! This foregut fermentation system manages to get all the nutrients possible from leaves, a low nutrient food source.. But they need to consume huge amounts of foliage to receive substantial energy!
The only way to describe these birds is awkward.. With a labored flight, crash landing, and flouncing gait, scientists have been puzzled by them. Well- it’s not exactly THAT that puzzles them..
It’s the claws which makes them living fossils. No, not talons like regular raptors.. Claws on the wings. The naked chicks use them to climb around branches and the nest. If they fall into water below, they can swim and climb up the nearest tree. Some say they’re the extant relatives of Archaeopteryx- although the claws aren’t unique to just Hoatzins. Geese have wing spurs they can retain to adult hood, and european coots have a single claw on each wing to get around their nests..
Photo by webgoers.