The word desert conjures up thoughts of camels traversing the lofty sand dunes of the Sahara or kangaroos in the arid expanses of the Australian outback. You get puzzled looks when you talk about the Monte desert of Argentina. Yet this is a great desert; just as hot, just as wild and just as deserted!
Immediately to its east the desert merges into the foothills of the spectacular Andes and to its west the vast flat thorn-bush lands of the Chaco. The Monte stretches over 1500 kilometres down central western Argentina and is one of South America’s great eco-regions. This is a region we wanted to discover for ourselves as well as to photograph its wildlife. After the great Cretaceous ‘break-up’ of the continents, the South American landmass drifted across the ocean for 65 million years. During this time two groups of mammals, that had previously been present when the landmass was connected to Africa, did supremely well in adapting to their new conditions, rodents and monkeys. But it was the rodents that adapted beyond all belief to their new environment, some attaining giant hippo-like proportions. These are all extinct, except one, but that animal will feature in a future blog as it is certainly not a desert animal. Suffice it to say that 40% of all mammals in South America are rodents and many of these do live in the Monte desert.
This rodent is a Yellow-toothed Cavy. Cavies are a family of Rodents. There are many species mostly living in desert and arid habitats and one or two species are otherwise known as Guinea-pigs. We found this species at two locations in the province of Mendoza, in the provincial reserves of Lake Diamante and Laguna Llancanelo.
This is a different species called Microcavia australis. We photographed it much more to the north, in the Province of Salta in the Los Cardones National Park. This rodent is diurnal, but the best time to see it is in the hours around dawn as it climbs into the low llarrea bushes to eat their fresh leaves, from which it derives moisture.
Wherever there are small mammals, there will be a predator to eat them and there is no more clever hunter of rodents than the Fox, this is the endemic Grey Fox.
There are a number of fox species all confined to Andean habitats, This Red Fox or Andean Fox, locally called a Zorro Colorado, is more widely distributed than the Grey Fox, its range extending the length of the Andes. This one heard a small animal underneath the bush, then spent 15 minutes, walking around the bush, peering in one side then another. Then after a mad digging session successfully emerged with what looked like a rodent. One swallow and it was gone !
Mara
As we were driving across the arid desert lands in Mendoza Province and saw two most peculiar animals run across a sand track. Quietly we stopped and spent an hour stalking them between the thick mesquite bushes. They knew of our presence even though we were upwind of them and as we moved slowly they moved faster, always trying to keep hidden. These were the elusive Mara, not a hare or an antelope but another rodent, the fourth biggest rodent in the world ! Very much a rodent of arid lands and the Monte desert in particular.
Camels and their ancestors have a peculiar evolutionary history. Believe it or not they originated in North America in what is now the Sonoran desert of Arizona and California. They travelled north and colonised Asia and then North Africa. Much later, only about 1-2 million years ago, they reached South America as part of the Great American Interchange that followed the formation of the Isthmus of Panama. There are two well known species, the Guanaco and the Vicuna, but it is only the Guanaco that lives at the lower altitude found in the Monte Desert.
Finally, to perhaps the most beautiful rodent in the world, the Southern Viscacha, closely related to the chinchilla. We were alerted to a colony of these as we were climbing a rocky outcrop in Salta Province, northern Argentina. We had heard high pitched whistles as though there was a raptor high above us but some minutes later as we climbed higher, one of these animals made a leap of perhaps 6 metres from one rock to another in front of us. It looked at us smugly, daring us to come closer.
Viscachas are vegetarian, eating mosses and lichens in particular. They live in loose colonies, are highly social and shelter in high rocky crevices. There are always several keeping guard, often looking upwards, as eagles and hawks are their main predators. It was, of course, their alarm whistles that we had heard as we approached them.
Because the Monte desert is so vast and stretches from sub-tropical to quite chilly latitudes it is not surprising that the range of landscapes and their associated plants are hugely variable, but some plant families species, such as cacti, can be found throughout the entire Monte, making it a distinct and rich eco-region.
