The only vertebrate that eats with its mouth shut

New Scientist

Image: Ryan Somma

The Pacific hagfish is the only vertebrate that can obey the cardinal rule of the dinner table: don’t eat with your mouth open. Uniquely among the 50,000 vertebrate species alive today, it can absorb nutrients through its skin.

Vertebrate skin is impermeable to minimise chemical exchanges between the body and its surroundings. This is why backboned animals can live in salty or fresh water – and how they avoid excess water loss on land.

But the primitive hagfish, thought to be as close as we can get in a living animal to the first vertebrate, has an internal salinity that matches its surroundings. So Chris Glover at the University of Canterbury in Christchurch, New Zealand, and colleagues reasoned that the animal might have a permeable skin. Read more on newscientist.com…