Today is Hagfish Day! Who knew?
What is a hagfish?
Hagfish are primitive eel-like chordates make famous for their relative unattractiveness*, profuse production of slime, and charismatic ability to tie themselves in knots. They are perhaps the only ‘fish’ that possesses a skull, but no vertebral column. But the question “What is a hagfish?” goes much deeper than that and it’s answer is fundamental to the evolution of vertebrates and, ultimately, us.