A Late Snowfall

It's a crisp morning in northern Argentina, early spring. The low cover of clouds glows ever brighter as the day begins, illuminating a broad sheet of fresh snow, blindingly white. If it were yesterday morning, the light would instead reveal little green buds sprinkled here and there in the otherwise brown tundra foliage. This time of year, temperatures never stay above freezing for long. The air, while biting and chilly, is gently warming as the sun rises, inviting many creatures out upon the fluffy white plains.

A screeching bellow suddenly erupts across the landscape. Two tundramas, both subadult males, have sized each other up and are beginning to brawl. They are huge, yet not fully grown; males of their kind may grow as large as bison and nearly as heavy. These two spent the winter in loosely-knit bachelor herds composed, ironically, of males bearing the cold together. With spring on the way, their mild tolerance for each other has turned into aggression in anticipation of the herds of females and yearlings are heading back from the warmer north. These behavioral and physical differences are in contrast to their ancestor. These two young studs - the term for a male llama, alpaca, or similar - slam each other with their necks, covered in thick hair for protection from both the biting cold of winter and the biting teeth of adversaries. They even stand upright as the fight escalates, screaming even louder.

Some distance away, a greater dusty opossum watches the conflict warily, trudging through the snow with difficulty. Though far smaller than the tundramas, its species is the largest of all opossums, weighing over 11 kg (24.3 lb). Its lanky, lean build disguised beneath a fluffy winter coat makes it seem even larger. Adapted to roam while retaining heat, it lives in the tundra and nearby taiga year-round. It has to travel far for food, taking any plant matter or carrion it can find, but preferring to corner smaller mammals to eat. This individual opossum has been walking for some time, looking to regain what fat it lost during the winter.

A keen eye can pick out a fourth creature in their mist, interesting in its own right: A fly is sitting on the glistening snow. This is a winter crane fly, a very unusual and poorly known insect which lives and breeds in the dead of winter. Other insects avoid the cold or, if adapted to it, have become tiny and wingless; this fly has done neither. On sunny winter days, these sizeable, black flies can be seen flitting about. Their larvae live here too, though beneath the snow eating organic debris in the moist soil. Thanks to their gift of flight, these animals have spread the world over, hence why they made it here from North America. They are a very valuable food source for a great many animals, so this one will be quick to take flight if disturbed.