Hoatzin: a two-minute wildlife lesson

Weird and Wonderful · day 5 of 7

Five facts

1. Hoatzin chicks have two claws on each wing, used to scramble along branches and climb through vines. They can even swim away from danger.
2. If a predator finds them, the chicks drop into the water, swim under the surface, then climb back to the nest with their wing claws.
3. The hoatzin ferments leaves in an oversized crop that acts like a rumen, breaking down up to 70% of plant fiber.
4. Its huge crop pushes its flight muscles aside, so it flies poorly. It eats leaves of over 50 plant species, including aroids that would harm us.
5. A 2015 genetic study suggests the hoatzin's family line split off on its own about 64 million years ago, just after the dinosaurs died out.

The quiz

1. How many claws does a hoatzin chick have on each wing?

• One
• Two (correct)
• Four
• Six

Chicks have two claws on each wing.

2. How do the chicks escape when a predator finds them?

• They freeze in the leaves
• They drop into the water and swim (correct)
• They fly to the next tree
• They dig a hole

They drop into the water and swim beneath the surface.

3. Which organ of the hoatzin acts like a rumen?

• Its stomach
• Its beak
• Its crop (correct)
• Its tail

Its massive two-chambered crop acts like a rumen.

4. How many plant species does the hoatzin eat?

• Over 5
• Over 15
• Over 50 (correct)
• Over 500

It thrives on a diet of over 50 plant species.

5. According to a 2015 study, about when did the hoatzin's lineage split from other birds?

• About 6 million years ago
• About 64 million years ago (correct)
• About 640 million years ago
• About 6,400 years ago

A 2015 genetic study dated the split to about 64 million years ago.

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