top of page


Happy Friday everybody, it’s time for another installment of Weird Biology! And today, you’re going to learn about a an actual real-life dinosaur. (Yes, I know all birds are technically dinosaurs, but this one is… dinosaurier? Dinosaurien? DINOSAURIEST than the rest.)


Relic of ages past.

*Raptor screech*

The Hoatzin is the only member of the family Opisthocomidae, an ancient line of birds that branched off from the rest some 64 million years ago. This would have been just shortly after the event that murdered the absolute cheese n' biscuits out of all of the non-avian dinosaurs. To death.

Hoatzins are the very last survivors of this ancient line. (I wanted to make a joke here, but that’s actually just really actually very tragic.)

Hoatzins are common pheasant-sized birds that live in the riverside forests of South America, where they survive on a diet of *drumroll* leaves. Yum. Seriously, they are one of exactly two known bird species to specialize in leaf-eating, having evolved past their shame trait some 30 million years ago. (The other one is the Kakapo, who mostly just seems confused.)

Their love of delicious delicious leaves gives them a very… distinctive odor, shall we say. This is due to their fermentative digestive process. It has earned the Hoatzin the local name "Stinkybird”, which (for any Hoatzins reading this), is really more of an affectionate nickname. Honest. But what truly sets Hoatzins apart, and proves their saurian nature, is this.


The hatchlings have functional claws on their wings. Remind you of anything? Like maybe, oh I dunno, this guy?


Archaeopteryx up there bears a striking resemblance to our Hoatzin friend, which did not go unnoticed by the scientific community. (Who was actually paying attention this time, they swear.) In fact, this uncanny resemblance helped finalize the theoretical link between dinosaurs and birds, Which we now know are the same actual thing. (More or less.) But anyway, the baby Hoatzins use those scientifically-groundbreaking claws to scramble around in trees and avoid predators. Also apparently the claws just kind of… fall off?.. When the bird becomes an adult. Like, imagine if your fingers all fell off at puberty, How weird would that be?

Thankfully, it looks like these evolutionary weirdos will be with us for some time to come, as Hoatzins continue to be plentiful in their range. We hope they and those weird dinosaur claws stick around for a long, long time.

Stink and all.


1. Carine06, Flickr

2. J. Arthur Thompson, Wikimedia Commons

3. James L. Amos, Wikimedia Commons

4. Bill Bouton, Wikimedia Commons

bottom of page