Every day, something new gets discovered. Just recently, hundreds of frog species were found in the Himalayas, of all places; pygmy seahorses were discovered by complete accident; as deepsea cameras and fishing get more and more advanced, countless monsters are found dwelling deep in the ocean. Humans like to think of themselves as the conquerors of the world, but given the sheer amount of discoveries still waiting to be made, it is impossible to declare mastery.
How do these things go so long without being found? The shortest answer is that life has a way of fitting everywhere. That does not mean that humans fit everywhere; that means that, no matter where on Earth you go, something has found a way to live there.
Some animals even live in plants. This is just as cute as it sounds.
All plants of the bromeliad family, which includes pineapples, have special leaves. Some are just waxy; others contain trichomes, which are the plant's only means of getting water; others are amazingly colorful. They are all native to the tropical Americas, which explains Europe's surprise when the Conquistadors brought back a pineapple. There was a lot more where that came from; bromeliads are versatile plants.
This is NOT a flower. Really.
The most stunning thing about bromeliads, however, is that their leaves can hold water amazingly well. This is usually common in epiphytic (tree-dwelling) bromeliad species. These bromeliads form little (or not so little) water tanks at the bases of their waxy leaves. These can hold as much as twelve gallons depending on the particular variety of bromeliad. This not only helps the plant get water if it does not already have a good root system, but creates a home for many other lifeforms.
Suddenly, living in a pineapple seems like a plausible idea.
Frogs (which could be any of MANY rain forest frog species, including the various dart frogs) are the most popular example of life in bromeliads. Some of them spend their whole lives in bromeliad pools, from swimming in the water pools and eating anything tasty that drops in to living in the leaves as adults.
Frogs are just the beginning. There is a snake called a "bromeliad boa;" the Jamaican bromeliad holds a specific type of crab in its leaves; the damselfly larvae that eat the young crabs live in bromeliads; snails, flatworms, and other squishy things also call a bromeliad home. Even other bromeliads live in bromeliads. By all standards, these plants contain their own miniature ecosystems.
This is how it works.
Of course, not all bromeliads are so hospitable...