Yesterday was a port day in Puerto Natales, and was pretty quiet. Some passengers took off on a guided tour of the city, or to see the Cueva del Milodón Natural Monument, a cave where the bones (and skin!) of a extinct giant ground sloth were discovered. As Wikipedia notes:
The largest cave in the monument is the 200 metres (660 ft) long Milodón Cave. It was discovered in 1895 by Hermann Eberhard, German explorer of Patagonia. He found a large, seemingly fresh piece of skin of an unidentified animal. In 1896 the cave was explored by Otto Nordenskjöld and later it was recognized that the skin belonged to Mylodon – an extinct animal which died 10,200–13,560 years ago.
It’s not just Mylodon, but the scientific name is Mylodon darwini. The “Darwin” bit comes from the fact that the first bones of this animal were found by Charles Darwin in 1832 on the Beagle expedition, embedded in a gravel cliff in Bahía Blanca, Argentina. From this fragment—a nearly complete lower jaw with teeth—paleontologist/biologist Richard Owen determined it was a giant ground sloth, naming it after his friend Darwin.
You can see the similarity to the mandible of the living two-toed sloth (image and caption from Science Photo Library). It’s clearly a herbivore, too, because the teeth are for nipping off vegetation and then grinding it with the back teeth:
Darwin himself recognized that the fossil jaw belonged to the same group as did modern sloths, and this recognition of the affinity between extinct and living creatures played a role, of course, in his theory of evolution. As he said in The Voyage of the Beagle:
“This wonderful relationship in the same continent between the dead and the living will, I do not doubt, hereafter throw more light on the appearance of organic beings on earth, and their disappearances from it.”
The giant ground sloths truly deserved their name: they were about as large as an elephant. Those in the genus Megatherium were among the largest land mammals that ever lived, measuring 6 meters from head to tail and weighing 4 tons. Here’s skeleton of a Megatherium from a Victorian print, and a reconstruction of Darwin’s specimen of Mylodon below:
Here’s Mylodon darwini. It wasn’t as big as Megatherium, but was still about 3 meters long and weighed between 1000 and 2000 kilograms:
Like their modern relatives, these group were herbivorous, dining on leaves and vegetation. The M. darwini specimen found in the local caves included, as I said, bones and fur, but also dung. Here’s some of the skin and fur found in the local Milodon Cave.
These animals went extinct about 12,000-10,000 years ago, so they were contemporaneous with humans, whose hunting may have helped reduce their numbers (the adult animals had no predators and were probably easy prey).
And here’s the 200-meter-long cave where the specimen was discovered:
We took our own self-guided perambulation around Puerto Natales, which is lovely and well-kept, but appears to cater largely to tourists, replete with expensive restaurants and souvenir shops. We were told that there were two good local brewpubs, but both were closed in the afternoon and our ship was scheduled to depart at 5 p.m. It turned out that the harbormaster refused to let our ship leave at that time because of high winds and waves, so we didn’t depart until some time after midnight. By then it was rainy and very windy (Puerto Natales is known for its winds, which can reach 100 mph), so we didn’t venture out for brewskis.
And now we’re steaming through the Patagonian fjords, late again and therefore unable to make a scheduled landing on Cape Horn, the southernmost tip of South America. I think the passengers are restive because several stops have been canceled due to technical problems and weather: the ship’s bar yesterday evening was packed.
The ship’s locator map shows us not far from Puerto Natales, and we’ll have to wait a bit later to go through another narrows (we can’t traverse narrows unless there is “slack water“: the interval between tides when there is little movement of water).
And a zoomed-out view. I’ll be heading back to Antarctica but then to the Falkland Island on the second part of this journey.