If you thought toe-tapping was out of style except within inches of an NFL sideline, you had bad information.
But so did everybody else, say three independent groups of scientists who recently examined bizarre pedal behavior in poison dart frogs.
One team studied the Dyeing poison frog (Dendrobates tinctorius) to find out why it sometimes tapped the middle toe on its back foot so fast it can look like a blur.
It often happens when prey is nearby. Scientists now think the frogs are “mechanostimulating” their soon-to-be meals (at about 500 beats per minute, or as fast as this thrashy black metal creation.)
What does that mean? Many of us have probably been mechanostimulated before. It happens at concerts, on trampolines, or if you’re the downstairs neighbor below an especially active second-floor tenant. This “mechanical stimulation of biological tissue” occurs when one percussive source sends vibrations through the body.
But that’s not all. The researchers, from the University of Illinois Urbana-Champaign also found the frogs tailored the tap dancing to other factors.
“In addition to confirming an association between tapping and feeding, our work demonstrates modulation of toe-tapping based on social context, prey accessibility, and substrate characteristics,” read the study.
The frogs could be using their dance moves to create the same effect stage performers want from their audiences, the study authors told The New York Times: to get their bodies moving. Dyeing poison frogs only eat live, moving prey, so making their quarry move and shake could make things easier.
Luring prey in
The drumming could also indicate luring behavior, like the deep-sea angler fish with its bioluminescent appendage.
Overall, the teams are convinced this still-mysterious toe-tapping relates most directly to prey interactions. A separate research team from Germany showed in 2023 that green and black poison frogs at the Frankfurt Zoo reacted to crickets and fruit flies with the toe routine, but didn’t respond the same way to calls from other frogs.
“It’s a potentially really interesting example of a predator using sensory cues to manipulate prey behavior — at least there’s that possibility,” Reginald Cocroft, a biologist at the University of Missouri, told the Times.
The teams all plan to advance their work, which could open a new window into predatory behavior among these amphibians.
