They are used to it in the wild - but a new fake ice surface proved too slippy for a group of penguins.
The gentoo penguins, which have been a star attraction at the Deep in Hull, since arriving a year ago, ended up scrabbling around on the new surface laid down during a maintenance programme.
Staff have now laid a new anti-slip surface in the display area, themed on an old whaling port in South Georgia in the South Atlantic, and hope the penguins will be back on show to the public by the weekend.
Assistant curator Andrew McLeod said: “We popped the penguins back in and they were scrabbling around as if it really were ice, so we thought we would have to put a bit more grip in there for them.
“We took the penguins out and out a new special anti-slip grip on, which is a bit like sandpaper - but you don’t want it too rough because it hurts their toes.
“We are just waiting for it to fully dry and we will pop them back in.”
The birds, which are found in the Falkland Islands, came from a Texas zoo where they were bred in captivity.
The future will see the younger birds bred with European individuals. They do not pair for life as suggested in rose-tinted Hollywood movies - and pairs of males can often prove better parents.