The bandicoot, besides having one of the best animal names in the world, is an Australian marsupial group with about 20 species. They are creatures that range in size from kind of small to very small, live on the ground, are omnivores, and look sort of like big, energetic shrews. It’s astonishing how much of the mammal world looks sort of like a shrew, really.
The word “bandicoot” essentially means “pig-rat” once you untangle and de-English it. As mentioned before, not only don’t we know exactly where bandicoots fit in the marsupial animal group, but they also have what is essentially a proto-placenta.
One of the things the makes marsupials a completely different type of animal is that they have no placenta. In placental mammals, including us, offspring grow relatively large while still inside the mother, gaining nutrients through the placenta. Marsupial babies are instead born very small and undeveloped, after which they live in the mother’s pouch and gain nutrient from milk.
While the bandicoot is definitely a marsupial, it has a very small and primitive type of placenta. The placental mammals did not develop from marsupials, so this is not some in-between form. Whether it evolved completely on its own by coincidence or whether it was some dormant part of the mammal lineage that in the marsupials only passed down to the bandicoots is uncertain. But there it is.
Some few reptiles and amphibians also form structures similar to a placenta, so it may just be something that is a part of our shared and very distant evolutionary lineage, the sort of thing that in most animals pops up only rarely but became a defining and consistent genetic feature of the placental mammals. In the same sort of way that syndactyly (fused fingers or toes) pops up now and then in animals, but is a consistent feature for kangaroos and their relatives (and also for bandicoots). Placentas are not the norm in the animal world, but the ancestor of all placental mammals happened — perhaps almost randomly — to have this feature, it happened to become a success, and it got passed down to everything from humans to rats to elephants to whales.
But back to bandicoots. Most live in nests that they build in dense or shrubby areas on the ground, or in fallen trees and such. As an ommnivore it eats just about anything, and female bandicoots have been known to even eat their own young when food is scarce. When times get tough it’s every bandicoot for itself, I suppose, but you know things are bad when your children start to look like chicken dinners.
Bandicoots live alone except for mothers with young, and though they are timid with other animals they will be quite aggressive and territorial with each other. Many bandicoot populations have decline on mainland Australia because of the invasive foxes and cats, and because of food competition with invasive rabbits.
One type of bandicoot, the northern brown bandicoot, has the shortest gestation period for young of any known mammal in the world. From conception to birth is only twelve and a half days. Yes, I know, every human mother in the audience is now frightfully green with envy, but perhaps you too could get it over with quickly if you were willing to pack the baby around in a pouch on your torso afterward.
Bandicoots are a primary natural storage tank for a bacteria called Coxiella burnetii, which can be passed, via ticks, to livestock. These livestock become infected and the bacteria comes out in their waste products. If a human happens to inhale the smell of these infected waste products, they might get the bacteria as well, and in this manner it can cause Q fever. It only takes one tiny bacteria to infect a human with Q fever.
The Q in Q fever stands for “Query”, because when it was first studied no one knew what caused it. It wasn’t until 1937 that the dastardly little bacteria was found. It can cause flu-like symptoms and pneumonia in humans, or in rare cases can cause hepatitis or chronic (ongoing) inflammation of the heart. As it is very contagious and easily transmitted, the United States has considered its use as a biological weapon. Since only one bacteria is needed to infect someone, it is a highly efficient disease.
Perhaps the bandicoots are getting us back for all those invasive species we introduced.