It's supposed to represent the prow of a ship in reference to Christian Salvesen as they provided the founders of the existing penguin colony and it's really why penguins have been at Edinburgh for so long as Salvesens used to regularly return to Leith docks in Edinburgh after trips to the southern oceans where they "collected" the penguins. There is a plaque on that part of the bridge at the penguin enclosure.
OK - but it's a pretty poor representation in my eyes. I doubt if any of Salvesen's factory ships or whalers had bows, sterns or anything else that were that shape or that colour. It would be another candidate for my Casson Memorial Wrecking Ball award if I didn't like the rest of the Penguin Pool so much.
Alan