Why do seals whisk their whiskers?

Seals are carnivorous marine mammals that are well adapted to hunting for fish underwater, where visibility is poor. In such conditions, seals rely on their highly sensitive whiskers to detect tiny water movements left behind by swimming fish. Like rats and cats, seals also move or “whisk” their whiskers back and forth, but the benefit of this motion was long unclear. New research by University of Groningen PhD student Chinmay Gupta, Professor Ajay Kottapalli, and colleagues shows that active whisking improves sensing, helping seals accurately follow underwater trails.

FSE Science Newsroom | René Fransen

Gupta and Kottapalli developed an artificial muscle system using soft actuators that mimics how seals move their whiskers. This system allows precise control of whisker motion and stiffness, helping them study how whisking affects sensing. They found that when whiskers are pushed forward (protracted), they become more sensitive but require active muscle effort. To balance sensitivity and energy use, seals keep their whiskers pulled back (retracted) and actively move them rhythmically to detect subtle water vibrations.

Navigating tight spaces

This discovery allows Kottapalli and his team to develop technology that could improve robots that operate both on land and underwater, inspired by seal whiskers. Robots equipped with whisker-like sensors could detect air or water movements and thus passively track trails left by moving objects. Unlike sonar, which emits ultrasonic waves that may disturb marine life, these sensors detect natural flow disturbances. This approach could enable quieter, more energy-efficient, and environmentally friendly robotic sensing and navigation.

In the future, Kottapalli and his team plan to expand this sensing approach to terrestrial robots. By integrating an array of whisker-like sensors, similar to those on an animal’s muzzle, robots could detect nearby objects and sense airflow. This tactile sensing could help them navigate tight spaces, operate in low-visibility conditions, and explore complex environments where cameras alone may not work well.

The study was performed in the Bioinspired MEMS and Biomedical Devices research group of the Engineering and Technology Institute Groningen, and was made possible through the continued support of the Seal Rehabilitation and Research Centre Lauwersoog, which provided seal whiskers for the research. The study was funded by a European Research Council (ERC) Starting Grant awarded to Kottapalli. The results were published in the journal npj Flexible Electronics on 20 March.

Reference: Chinmay Gupta, Anastasiia O. Krushynska, Bayu Jayawardhana, Liangliang Cheng & Ajay Giri Prakash Kottapalli: Soft bionic actuation explains the functional role of whisking in seal whisker sensing. npj Flexible Electronics, 20 March 2026