A Crocodile Dictionary.

Anthony Ham reported for the NY Times back in August (archived) on attempts to understand a nonhuman species:

A male saltwater crocodile approached a female saltie — as they’re known in Australia — in the same enclosure at Australia Zoo. He snapped at her aggressively. But then in a change of heart that wasn’t what you’d expect from one of Australia’s most fearsome predators, he appeared to think better of it. “He went down under the water and started blowing bubbles at her,” said Sonnie Flores, a crocodile researcher at the University of the Sunshine Coast who observed the interaction. “It was kind of sweet. It was almost like he was blowing her a kiss.”

Trying to decipher what crocodiles like that one are saying is at the center of ongoing research by Ms. Flores and her colleagues to create the world’s first crocodile dictionary. Such a gator glossary would catalog different forms of crocodilian communication and unlock their meanings. If successful, it could even help prevent conflict between humans and crocodiles.

Like all reptiles, crocodiles and alligators don’t possess a larynx and their vocal cords are rudimentary. And unlike those of most mammals, crocodilian lung muscles can’t regulate the vibrations of those vocal cords. But crocodiles and alligators have overcome their physical limitations to become the most vocal of all reptile species.

After studying recordings and video footage from captive crocodiles at Australia Zoo, and from wild crocodiles on the Daintree River and Cape York Peninsula in the northern Australian state of Queensland, Ms. Flores has identified 13 categories of crocodile sounds. These include growls, bellows, coughs, hisses and roars. But there are also nonvocal forms of “speaking,” like head slaps on the water, narial geysering (when a crocodile dips its nose beneath the water and spouts water into the air), narial toots, and, yes, blowing bubbles. […]

Most intriguingly, crocodilian species communicate using vibrations at very low frequencies known as infrasound, which Dr. [Vladimir] Dinets said “should be physically impossible.” “Their ability to produce infrasound is interesting because usually you have to be the size of a big whale to produce infrasound underwater,” said Dr. Dinets, who is not involved in the crocodile dictionary. “And yet crocodilians have found some physical mechanism that allows them to do it.”

Having identified how crocodiles are communicating, scientists are now trying to unlock what they’re actually saying. […] Scientists hope that a crocodile dictionary could help improve human-crocodile relations.

Northern Australia has an estimated 130,000 wild crocodiles and, with crocodile numbers rising, more salties are moving into landscapes dominated by humans. Detecting and understanding crocodile sounds could help the authorities set up early warning systems whenever a crocodile is active in an area. It may even be possible to drive potentially threatening crocodiles away using playback of certain sounds underwater.

A crocodile dictionary could also facilitate crocodile conservation, by detecting when crocodiles are distressed or hungry. Unlocking crocodile communications could even help to change popular attitudes. “Crocodilian behavior is much more complicated, and they’re much more intelligent than most people realize,” Dr. Dinets said. “My hope is that once this becomes more widely known, people will start to see them in a different light, and not just as something that tries to eat everything that moves.”

I find animal communication fascinating, and I’m glad it’s being reported on more responsibly — perhaps the era of “ridiculous, credulous garbage” is drawing to a close.


  1. David Eddyshaw says

    If you can speak crocodile, it is all the more important to observe crocodilian norms of etiquette:


    However, if a crocodile should speak, we would not understand him.

  2. Good points both.

  3. I recommend “Animal Languages” by Dutch philosopher and writer Eva Meijer (https://www.evameijer.nl/en/bio.htm) where she challenges our hierarchical thinking re animals and intelligence and provides quite amazing findings on various research projects. Also Katy Payne “Silent Thunder” on elephant communication.

  4. But do crocodiles have recursion?

  5. At least, they have embedding.

  6. Stu Clayton says

    They repeatedly have recourse to action. It always terminates, fatally or not. If that ain’t recursion I don’t know what is. Tail recursion has been reported as “thrashing and rotating”.

  7. David Eddyshaw says

    Crocodiles are really an example to us all.

    They need better PR, though. And there is a lot of crocodilism about these days.
    I blame Peter Pan. Also, violent video games.

  8. Stu Clayton says

    Allegories, in contrast, are treated with exegetic respect. Despite their reputation of wilfulness.

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