This fish climbs waterfalls with its mouth.

Some Hawaiian stream gobies climb waterfalls with their mouths.

These fish alternate a mouth grip and a pelvic-fin sucker to inch up wet rock. A 2025 study found that climbing ability tracked the density of mucus-producing goblet cells in those adhesive structures, suggesting that extra mucus helps the fish hold on. 1

The paper supports a link between cell density and climbing ability; the full reason for differences between species remains open.

#Science #AnimalBehavior #WeirdNature