Plural of crepitaculum; small structures or organs in some animals (particularly certain snakes) that produce crackling or rattling sounds.
From Latin crepitaculum (a rattle or noisemaker), from crepitare (to crackle or rattle) + -aculum (instrumental suffix), with standard -a plural ending.
Crepitacula in rattlesnakes are modified tail scales—they produce sound by vibrating against each other, creating a warning rattle that's one of nature's most effective deterrent systems!
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