When on the iceberg ship, Sid the Sloth says "water water everywhere, but not a drop to drink". This is from "The Rime of the Ancient Mariner", a poem written by Samuel Taylor Coleridge in 1798. The actual line from the poem, however, is "Water, water everywhere, nor any drop to drink."
Initially in production Gutt was designed as a bear, but in the end, Peter DeSève, the film's art director, settled on an ape, due to the ape's flexibility and four hands, which seemed more fitting to have him swinging on the ship's rigging.
Peter DeSève designed a number of animals for the film that never made it to the final cut: eohippus (prehistoric horses), a large horselike animal that Sid would have ridden, a giant squid and a number of prehistoric sharks that would have nearly eaten Granny in the scene in which she takes a bath in the ocean.
The Earth's Core information screen (seen when Scrat is falling to the center of the Earth) reads "Fig 4.1: The inner core is 6,000 kilometers below the earth's surface and composed primarily of molten lava. It is often drawn in textbooks to look like a floating pinball. Fun fact: It's near 7,000 C down there, so bring your oven mitts! Blue Sky Studios takes no responsibility for the scientific accuracy of the information presented here."