Blacktip sharks can hear and locate sounds up to 74 meters away, study finds

Blacktip sharks can detect low-frequency sounds from as far as 74 meters (243 feet) away and determine which direction they come from, according to a field study by researchers at Florida Atlantic University. The work, published in the journal Integrative Organismal Biology and announced on September 24, 2026, was carried out in open water off Southeast Florida rather than in a tank.

The paper is titled "Orientation of Blacktip Sharks (Carcharhinus limbatus) to Underwater Sound."

Testing hearing in the wild

The researchers worked in shallow nearshore waters along the Palm Beach County coast. They played controlled sounds through an underwater speaker, measured them with calibrated hydrophones, and filmed the sharks with a drone flying 40 to 50 meters above the water, according to Phys.org. They then measured changes in each shark's direction frame by frame.

The team tested three low-frequency ranges, 100 to 200 Hz, 200 to 400 Hz and 400 to 800 Hz, and used a 10-kilohertz sound, outside the sharks' hearing range, as a control. The speaker drifted up to 19 meters from the boat during trials.

Blacktips were chosen because they gather predictably off Southeast Florida, with large numbers along the Palm Beach County coast each winter, according to the university. "Their abundance and accessibility made it possible for us to observe them from above without disturbing their natural behavior, while also presenting controlled underwater sounds," said senior author Stephen Kajiura, a professor of biological sciences at the university.

Kajiura also explained why the work was done outdoors: "Trying to do hearing experiments in a tank results in the sound bouncing off the walls which causes complex and confusing signals."

Turning away from the sound

According to the university's release, "the animals often made rapid turns away from the speaker. That behavior indicates that they were not simply detecting the presence of a sound. They could also determine the direction from which it was coming."

The sharks were more sensitive to the lower frequencies tested, Phys.org reports.

Hearing beyond the near field

More than 70 percent of the recorded responses occurred in the acoustic far field. Kajiura said: "What makes this finding particularly interesting is that the sharks were responding to sounds beyond the acoustic near field, where the sound behaves differently." According to the release, this suggests the sharks detect the particle motion associated with sound even at considerable distances from the source.

The study was led by Caroline Sullivan as part of her master's degree research. "The next question is how their sensory system allows them to pick up and interpret these distant sounds," she said.

Why it matters

Much of what is known about shark hearing comes from laboratory tanks, where echoes off the walls make sound signals hard to interpret. Measuring responses in open water gives a more realistic picture of how far sharks can hear and how they use sound to sense their surroundings.

Sources

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.