The stinkbird that digests leaves like a cow and has clawed chicks
This bird digests leaves like a cow, smells like manure, and its chicks have claws on their wings.
Which one is REALLY true about the Hoatzin?
The short version
The hoatzin is a punk-haired Amazon bird that eats mostly leaves and ferments them with bacteria in a huge crop, cow-style — giving it a manure-like stink. Its newborn chicks have two working claws on each wing to climb back up after leaping into water to escape predators; the claws vanish as they grow.
Why it's so weird
- ✓The Hoatzin eats mostly leaves and ferments them with bacteria in a huge crop, just like a cow does.
- ✓The Hoatzin smells strongly of manure, which is exactly why local hunters tend to leave it alone.
- ✓The Hoatzin is born with two working claws on each wing when it is a tiny chick.
- ✓The Hoatzin leaps into the water to escape , then climbs back up the branches using those wing claws.
- ✓The Hoatzin slowly loses its wing claws as it grows up, looking like a bird from the age of dinosaurs.
You could line up about 2 of them along a 7-year-old!
The full story
This bird ferments its food like a cow and smells so bad that people call it the stinkbird. Meet the hoatzin, a bizarre, punk-haired bird from the swamps of the Amazon. Unlike almost any other bird, it eats mostly leaves, and it digests them using bacteria in a huge, specialized crop, the same way a cow's stomach works. That fermentation gives it a strong, manure-like smell, which is exactly why local hunters tend to leave it alone. But the strangest part is its babies. Newborn hoatzin chicks are born with two working claws on each wing. If a predator attacks the nest, the chicks leap into the water below, swim to safety, then use those tiny claws to climb back up the branches. As they grow up, the claws slowly vanish. A stinky, leaf-eating bird that looks straight out of the age of dinosaurs. Follow for more weird animal facts.
Leaves are full of cellulose, a tough fiber the hoatzin's own body can't break apart. So the bird keeps a huge crowd of special bacteria in its big crop (a stretchy pouch in its throat), and those tiny microbes slowly ferment the mashed leaves, turning the cellulose into nutrients the bird can soak up for energy — the exact same trick a cow uses in its stomach. The smelly, gassy leftovers from all that fermenting are what make the hoatzin reek like manure.
📚 Source: Comparative analyses of foregut and hindgut bacterial communities in hoatzins and cows (The ISME Journal, via NIH PMC) ↗When scientists sampled and DNA-sequenced the microbes living inside hoatzin crops and cow stomachs, they found the same kinds of fiber-fermenting bacteria in both, showing the bird really does digest leaves the cow way.
📚 Source: Comparative analyses of foregut and hindgut bacterial communities in hoatzins and cows (The ISME Journal, via NIH PMC) ↗Watch the 45-second version
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“The Hoatzin eats mostly leaves and ferments them with bacteria in a huge crop, just like a cow does.”
“The Hoatzin can survive a venomous cobra bite by simply napping off the venom.”
“The Hoatzin smells strongly of manure, which is exactly why local hunters tend to leave it alone.”