From the course of school biology in our memory remains that pollen from flower to flower is transferred, mainly insects. Or wind.
That's only nature often have such a trick that you wonder.
It turns out that cross-pollination can occur with fairly large or very small animals, and not only insects.
So, about hummingbirds-pollinators of orchids and hibiscus is known to many (ornithophilia, or pollination by birds. More than 2000 species of such birds are described).
The flowers of these plants emit a lot of nectar. The smell is almost absent (in birds the sense of smell is poorly developed).
The less you know about pollinators-bats. Pollination with mammals is called zoogamy.
But quite exotic cases of pollination - is the transfer of pollen ... squirrels and kangaroos.
For example, on the island of Java shows cases where proteins transferred pollen from the inflorescence to the inflorescence, eating juicy apical parts.
In Australia kangaroo muddy face in the pollen when you drink the watery nectar from the huge flower of a shrub of the genus Driandra.
Moving from plant to plant, kangaroos pollinate flowers.
Indeed, the way evolution works in mysterious ways.