For years, experts believed that giraffes didn’t really communicate vocally. After all, many zookeepers thought, it would be pretty difficult to force enough air past their voice boxes to make any sort of sound aside from a snort, considering the length of their necks. But as it turns out, giraffes spend their nights humming to each other.
Since it would take a lot of airflow to make a loud sound from a giraffe’s 13-foot-long trachea, researchers believed that giraffes had no form of vocal communication and instead relied on their keen sense of sight. But according to a new study by researchers from the University of Vienna, giraffes do communicate vocally after all – it’s just that the sounds they make are so low that it’s hard for humans to hear them.
Initially, the researchers wanted to test a long-standing theory that giraffes could “talk” using infrasonic frequencies too low for the human ear, much like elephants and some other large mammals do. To answer the question, they spent almost 1,000 hours recording giraffes at three different European zoos and painstaking analyzed the waveforms by sight, looking for patterns. While they didn’t find any evidence of the giraffes using infrasound, the scientists realized that the giraffes would spend their nights humming.
Because giraffes seem to only hum at night, scientists have yet to figure out whether it correlates with any behavior or if it’s just snoring. However, it’s possible that the humming might be used to communicate all sorts of information from age, gender, social dominance and sexual arousal.