There are 5 or 6 dinosaurs 'lost' on Wake Island in the latest Battlefield 3 DLC. What are they there for, or what do they trigger once you find them?
They're an easter egg put in the game due to a meme that spread around the internet originating on 4chan because of a lack of dinosaurs in Call of Duty: Modern Warfare 2.
Basically when Battlefield 3 was announced, everyone was asking if there'd be a dinosaur mode.
Since they weren't actually putting a dinosaur mode in (or maybe they will in the future :P) they left lots of dinosaur related easter eggs around, one of them being the dinosaurs on Wake Island, another being the Dinosaur Dogtags and a third being this wallpaper that they circulated: