Honey, I shrunk the possum. (Image by John Gould)
The honey possum is an itty-bitty opossum found in extreme western Australia, which weighs only about half as much as your average mouse. It is not closely related to any other possum, but that’s not what makes it strange. What makes it strange is that the honey possum is one of the only mammals, along with some bats, that is a nectavore.
A nectavore is an animal that survives mostly through eating nectar from flowers, though some nectavores are also insectivores. A nectavore is typically doing the flower a favour — the nectar is a sweet treat to tempt the animal in to feed, and in return the animal accidentally gets pollen on its feet or body, which it transfers to other flowers and so helps the flowers reproduce.
The honey possum is one of those animals that lives entirely off nectar. Because these possums are very small and cannot fly like many other nectar-eaters, they need lots of flowers in a small area in order to survive. As a result, they are quite common in their particular corner of Australia but cannot really venture any further as a species, since most of the continent is dry and spread-out.
In order to get at nectar, the honey possum has a long nose and an even longer tongue, and the tip of its tongue is bristled to help gather more nectar. It is essentially the mammal equivalent of a flightless hummingbird.
Because of competition for females during breeding season, male honey possums have the largest testes relative to body weight of any mammal in the world — the exact figure is 4.2 percent of body weight. Their sperm is also the largest of any mammal’s. So when it comes to questions of masculinity, you must ask yourself: are you a man, or are you a honey possum?
The Book of Beasts 