The Link Between Birds and Alligators

The crocodilians — crocodiles and their relatives, like the American Alligator — are the closest living relatives of birds. About 250 million years ago, the ancestors of all crocodiles split off from the dinosaur group that gave rise to modern birds. While crocs these days are mostly short-legged ambush predators, before mass extinction there were ocean-dwelling crocodilians and even species that ran around on two legs.

BirdNote®
The Link Between Birds and Alligators
Written by Conor Gearin

This is BirdNote.

    [Florida wetland soundscape]
  [Tricolored Heron calls]

The familiar birds of the present are the direct descendants of dinosaurs. But there’s another group of animals that you might say looks pretty prehistoric. And that’s the crocodilians: crocodiles and their relatives, like this American Alligator.

[American Alligator growl]

Crocs are the closest living relatives of birds. The ancestors of all crocodiles split off from the dinosaur group about 250 million years ago. Dinosaurs diversified into all kinds of lifestyles: herbivores and predators,

[Red-tailed Hawk call]

big and lumbering,

[Canada Goose honk]

small and nimble.

[Verdin call]

Crocodilians diversified too: there were ocean-dwelling crocs and ones that ran around on two legs, like some well-known dinosaurs. But mass extinction events hit the crocodilians hard. These days, crocs are scaly, short-legged and ambush their prey from shallow water. They don’t share many of the unique adaptations of birds, like feathers and impressive vocal abilities.

[Black-capped Chickadee calls]

That said, gators definitely know how to growl.

[American Alligator growl]

It’s a far cry from the dee-dee-dee of a chickadee. But both voices carry on the legacy of ancestors that lived long, long ago.

[Black-capped Chickadee calls]

For BirdNote, I’m Ariana Remmel.

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Senior Producer: John Kessler
Producer: Mark Bramhill
Managing Editor: Jazzi Johnson
Managing Producer: Conor Gearin
Content Director: Jonese Franklin
Bird sounds provided by The Macaulay Library of Natural Sounds at the Cornell Lab of Ornithology, Ithaca, New York. Environmental ML138399 recorded by Gregory Budney, Tricolored Heron ML229127 recorded by Bob McGuire, American Alligator ML163791 recorded by Arthur A. Allen, Red-tailed Hawk ML229578 recorded by David McCartt, Verdin ML312454621 recorded by Andrew Spencer, and Black-capped Chickadee ML199076 recorded by Bob McGuire.
BirdNote’s theme was composed and played by Nancy Rumbel and John Kessler.
© 2024 BirdNote January 2024
Narrator: Ariana Remmel

ID# alligator-02-2024-01-05 alligator-02

References:
https://www.science.org/doi/10.1126/science.1254449
https://news.ucsc.edu/2014/12/crocodile-genomes.html
https://www.smithsonianmag.com/science-nature/modern-crocodiles-are-evo…
https://www.researchgate.net/publication/232678368_The_Early_Evolution_…