Dozens of Pacific lamprey eels arrived at Oregon Zoo in Portland.

The 25 eel-like creatures, which have species dating back 400 million years, were introduced to the Great Northwest area of the zoo.

Zoo officer Jen Osburn Eliot said: 'We're thrilled to have the lamprey back at the zoo. It's an incredible opportunity for our guests to observe and learn about these fascinating creatures, their evolution, and their significance in our region's history.'

Located in the Cascade stream and pond section, the lamprey can often be seen attached to the glass of their habitat, showcasing their distinctive sucker-like mouths and rows of sharp teeth.

The Pacific lamprey, characterized by a jawless mouth and smooth, scaleless body, has endured millennia of environmental changes, including multiple ice ages and mass extinctions. However, their numbers have dwindled in recent decades due to habitat loss, climate shifts, and food scarcity, prompting conservation concerns.

The zoo aims to conserve them in collaboration with the Confederated Tribes of the Umatilla Indian Reservation.

Oregon Zoo will temporarily shelter them before they are released into their natural spawning grounds in the upper Columbia and Snake Rivers.