Something Really Weird Happens When a Cane Toad Sits Down to Eat

It isn't possible for you to swallow your own tongue. At least if you are a person. Every time a toad eats, they do it on purpose.

Prior to this study, everything that happens after a frog closes its mouth was unknown.

The results of using high-speed X-ray videos to work out what happened when the salamanders slam their mouths shut around a meal were completely unforeseen.

We weren't sure what was happening. The entire floor of the mouth was pulled backwards into the throat.

It took months of studying the cane toads, as they ate hundreds of crickets and created 3D animations to puzzle out the feeding mechanism.

The problem Frogs had to solve was how to get the food from that clingy whip to send it down their guts.

The entire process takes under two seconds, but there are a lot of events happening within the toad.

The team attached metallic beads to the toad's tongue to record its movements in the x-ray. The orange marker at the tip of the toad's tongue can be used to grab an insect. It continues down the throat until it almost touches the toad's heart.

The researchers wrote in their paper that the tongue's maximum protrusion was 4.1 centimeters on average and that the mean distance that the tongue stretches during retraction is equivalent to or exceeds the mean distance that it stretches during protrusion.

The hyoid is a flexible plate that snaps shut against the tongue.

"The hyoid shoots up and presses the tongue against the roof of the mouth, after which it moves forward, essentially pulling the food off into the stomach."

Some toads use the hyoid to seal the floor of their mouth while they rest. The toad's connection to the tongue means it flings open as it gaps its mouth, ready for the tongue's snap back.

The ridges or bumps on the roof of the toads' mouths are likely to help with food de-sticking. The researchers used hyoid markers to make a 3D reconstruction. The flexibility of the hyoid would help it.

The prey remains attached to the tongue throughout manipulation even if a toad moves the tongue. The hyoid mechanism can be used to get food out of a frog's mouth.

There is a huge diversity of hyoid and tongue shapes in nearly 5,000 frog species and the researchers want to know if this tongue recoil and scraper feeding mechanism is universal.

The research was published in a journal.