Geoscience Reference
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Acyclonethathitthisareajustalittlemorethanayearbeforehadrippedopenparts
of the canopy, illuminating the way. Otherwise, deep shade in the middle of the af-
ternoon might have subdued our collective mood. Confident that our loud, boister-
ous group—with American accents, no less—had probably frightened off all wild-
life for the day, I stopped paying attention to the songbirds in the rainforest canopy
above and around us.
This was a mistake. Had I been eavesdropping on these avian conversations,
they first would have alerted me to two people walking on the trail about a hundred
meters behind us. These songbird scolds would have been followed by a brief mo-
ment of quietude, as a second large disturbance—which slipped into the forest, hid,
and waited for our group and the couple to pass by—emerged and walked on the
trail behind them. Instead, I only saw the couple come out of the woods and walk
on a low, narrow footbridge over a stream our group had just crossed. I returned to
idle chatter with a few of the students, all of us snapping photos of the gorgeous
rainforest around us. We were clueless.
The low-frequency boom was subtle enough that at first I dismissed it. This
was a lesson in observational blind spots, in which a lack of training in perceiving
something new, but very real, can be quickly unnoticed or rejected. The second
boom registered more firmly, though, and I realized it came from something alive,
in the forest, and getting closer.Abehavioral relic ofmy Cenozoic primate heritage
washandilyexpressedasthehairsonmynecksprangupindirectresponsetoashot
of adrenaline. Something was wrong, but I didn't know what.
Nearly every dinosaur documentary that attempts to recreate dinosaur noises
usesmammalianoravianvoices,orablendofanimalcallsthatsomehowmanageto
reach some familiar place in our expectations of what dinosaurs should sound like.
Even in fiction, such as during the unforgettable scene of the first
Tyrannosaurus
attack in the movie
Jurassic Park
, this theropod's petrifying roar actually was an
amplified mix of sounds from an alligator, tiger, and elephant. Shaped by cinematic
conditioning, we expect large theropods to roar or snarl, smaller theropods to hiss
