Hiking the Cross-Island Track (Rarotonga). 'A Cook Islands sojourn usually involves lots of good eating and drinking, and lazy days on the beach. The perfect balance to this tropical relaxation is to challenge yourself on Rarotonga’s Cross-Island Track. The three- to four-hour hike via the 413m-high Te Rua Manga (The Needle) immerses walkers in some of the island’s most spectacular scenery.' http://www.lonelyplanet.com/rarotonga-and-the-cook-islands/rarotonga
Barn owl: "The wise old barn owl is one of the most widespread birds in the world. In Europe and the Americas it is seen as the farmers' friend because it eats so many rodents, yet on tropical islands the barn owl's surperb tracking equipment is having a devastating impact on populations of rare, nesting seabirds." 100 Alien Invaders; www.bradtguides.com
Cusk eels (Ophidiidae) feed only at night, tracking prey by using their pectoral fins to sense vibrations. Found in temperate and tropical oceans throughout the world, they have been seen in waters 27,460 feet deep at the bottom of the Puerto Rico Trench, which happens to be the deepest fish sighting on record.
Ceiba Tree. Ceiba is the name of a genus of many species of large trees found in tropical areas. Some species can grow to 230 ft tall or more, with a straight, largely branchless trunk that culminates in a huge, spreading canopy, and buttress roots that can be taller than a grown person.