Readers ask about noise pollution and beluga melons

People exposed to noise pollution during pregnancy may have an increased risk of developing gestational diabetes, gestational hypertension and preeclampsia, some studies suggest. A study published in May in JAMA Network Open also found that children and adolescents living in the United Kingdom in areas with high traffic noise have an elevated risk of anxiety.

One in a melon

Captive beluga whales warp their forehead fat, called melons, into distinct shapes when they’re around other belugas, Elizabeth Anne Brown reported in “Belugas may communicate via ‘melons’ ” (SN: 6/1/24, p. 9).

Reader Jim Sobek wondered whether changing the shape of the melon helps the belugas better hear each other during “conversations” by boosting or focusing sounds that they produce and receive.

Belugas and other toothed whales typically hear through their lower jaws and inner ears, so the melon is unlikely to play a role in receiving sounds, says Malin Lilley, a comparative psychologist at Texas A&M University–Central Texas in Killeen.

But toothed whales are known to use their melons to transmit and direct echolocation clicks and other vocalizations into the environment. So it’s possible that belugas warp their forehead blobs to alter the acoustic properties of their vocalizations, says animal behaviorist Justin Richard of the University of Rhode Island in Kingston. However, the visual aspect of the behavior seems key to belugas’ social interactions, since the animals change their melon shapes primarily when other belugas can see them, Richard says. Studying the potential auditory components of this unique beluga behavior is an important next step in understanding its role in the whales’ banter.