Ice Age Giants

iceagegiantsmammothThere have been lots of documentaries on dinosaurs, but the path of programmes focusing on extinct prehistoric mammals is not quite as well-trodden. BBC 2 showed a 3 part series about that subject presented by Professor Alice Roberts. The programme used computer animation similar to shows like Walking With Dinosaurs to illustrate examples of what might have gone on back then.

The mammals are ancestors of some animals we still have in the present day, and the ones in the Ice Age tended to be much larger. To misquote the Doctor in the Doctor Who episode Cold War; “It’s the Ice Age, everything’s bigger!”.

In the first episode Land Of The Sabre Tooth the programme goes into what today is Hollywood, Los Angeles and as Professor Alice Roberts called it “an encounter with the most iconic Ice Age celebrity”. That is Smilodon, a type of sabre-toothed cat. It’s probably more well known as the sabre-toothed tiger, although this term is scientifically inaccurate. Just like Brontosaurus (to cut a long story short, they found out that a Brontosaurus wasn’t a species in its own right, but was in fact just a type of Apatosaurus) we have a term that has long been discredited scientifically, but has entered the public consciousness to such an extent that they would probably be mentioned if you asked a random member of the public to name as many prehistoric creatures as they could. The “sabre-toothed tiger” wasn’t related to tigers we see today.  I wonder if they are trying to make “sabre-toothed cat” something that is more prevalent as a public name? It does make me think more of domesticated cats though. Actually, it reminds me of Baby Puss, the pet sabre-toothed cat in The Flintstones who always locked Fred Flintstone out of his home in the end credits. We get to see the milk teeth of a sabre-toothed kitten.  Big “awwwww” factor there, but those teeth were still as sharp as a knife blade.

I’ve always wondered how so much is known about prehistoric life with so little to go on other than fossils. But it’s surprising at just how much you can tell from them. From mastodon tusks experts can tell the age of the creature when it died, whether it was eating a lot or a little, if they were pregnant and even if they were suckling their calf. The remains of snails and beetles and soil samples can tell us even more about what the environment was like, such as what sort of plants were around and a rough guess of how many of them there were. For instance we know there were traces of buttercups, poppy seeds and bluegrass  during the ice age, which are very varied plants, though what all of them have in common is that they are suited to cold climates.

Nothrotheriops Shastensis, the Shasta ground sloth, is long extinct, but it used to live near what is now the Grand Canyon. What it has in common with present day sloths is that it took a long time to digest its food, which is the very reason why sloths are slow. The Shasta ground sloth was much bigger than today’s sloth though, it was as big as a grizzly bear and had 7 inch long claws.

In the second episode Land of the Cave Bear one of the created CGI scenes was of a bear and a lion fighting in a Transylvanian cave. Sounds kind of like a wildlife themed Tekken/Street Fighter-ish video game. The event was was suggested to be something that might have happened as remains of both cave bears and cave lions were found in that location The cave bear was very large and was a vegetarian, and needed to consume a great deal so it would have enough energy to hibernate. But falling temperatures during an ice age meant less vegetation, so many cave bears couldn’t get enough to eat and died during hibernation. Within just a few thousand years they were extinct. The cave lion was 25% larger than modern day lions and didn’t normally hunt cave bears, in fact it attempting to attack one at all suggests conditions were harsh for them too, as cave lions preferred to hunt antelope and reindeer. Their numbers also probably fell because of the lack of vegetation.

Some species thrived during the ice ages however. The Glyptodont is one, who lived in what is now Arizona and where evidence suggests that their numbers correlated with the advancement or recession of the ice sheet. The Glyptodont was a very unusual mammal. It had a shell, a furry belly, digging claws, teeth which looked a bit like Christmas trees, and it may even have had a trunk! It was described on the programme as resembling an “enourmous armadillo”. It was suited to swamps, but when the ice age began to thaw the rains moved north, which caused their habitat to be drier turning it into a desert. This is probably what led to the Glyptodont’s extinction.

Two species that were extremely well suited to ice age conditions were the woolly rhinoceros and arguably the most well known ice age creature the woolly mammoth. Both were covered in woolly fur to keep them warm. The woolly rhinoceros was about the same size as modern day rhinos, but it’s horn was twice the size of the horns on the rhinos we see today. The fact that two large herbivores were so widespread during this time, from Siberia to Alaska, suggests that there must have been plenty of plants for them to eat. This is the odd thing about the Ice Age. It was probably quite sunny in this area even though it was extremely cold.  The theory is that because there was so much ice which wasn’t thawing it locked up most of the water, meaning that as cold as the temperature was very it was also dry so there would be very little snow. Ironically as the planet warmed up it would have become more snowy, which would have been difficult for both those species to navigate through and to find food.

Woolly mammoths clung on for a while though, there are traces of them as late as 2,000 BC, which was around the time the Egyptian Pyramids were built. They chose to move further north where it was colder, although the newer fossils are a lot smaller. It seems that mammoths may have been evolving to become smaller.

The conclusion drawn in the third episode Last Of The Giants was unfortunately that humans probably have the most responsibility for the extinction of woolly mammoths and mastodons. They were hunted by our ancestors and Neanderthals. Our ancestors used mammoth carcasses for a lot of things.  There is evidence that they used mammoth bones and tusks as fuel because trees were so scarce, and the tusks and hides were used to build early forms of houses. It’s unlikely that they were solely to blame for the animals extinction, as they’re simply weren’t that many homo sapiens around at this time, but it’s definitely possible that they set off a chain of events over a long period of time.

A theory the programme puts forward is that fossils show that mammoths may have started attacking one another. In modern day elephants dominant bulls are targeted by poachers because they are solitary and have such large tusks. This causes problems for elephant herds as the large elder bull elephants keep the younger testosterone fuelled bulls in line, and without their presence the younger bulls fight amongst themselves, with the females and their calves getting caught in the crossfire. It’s likely that our ancestors targeted the elder bull mammoths and mastodons with the biggest tusks, so perhaps a similar thing happened to these species.

Of course if our ancestors hadn’t developed to use tools to hunt is probably what allowed humans to survive the Ice Age and become as sophisticated and powerful as we are today., They also left behind cave paintings, such as the famous ones in Chauvet cave in Southern France.  We also saw a carving of a bison, which I thought looked very well done considering how primitive the time it is from. There were also animals which benefitted from our presence, horses being an example. The first horses were born in America, but eventually died out there. Luckily by that time they had spread throughout Europe and Asia, and to Africa where they evolved into zebras, and the fact that humans domesticated horses would only have helped their numbers increase.

As tempting as it is to think that one cataclysmic event is what killed off all the extinct Ice Age mammals, it seems it was more many events over a long period of time. There were many disastrous events. When the ice started melting it didn’t just unleash the water it contained, it released any water it was holding back like a dam causing floods which would have killed anything in their path, and even if the ice didn’t melt altogether the icebergs of the time were as big as islands.

There were many Ice Age animals that survive to this day. The ones mentioned in this programme included elk, bison, antelope, Arctic ground squirrels, capybara and of course, us.

But if there is a trend as to what killed the extinct animals it’s that the climate changed slowly but surely, having a knock-on effect. With the talk of ice melting, climate change and in the case of the extinction of mastodons, humans not knowing the long term consequences of their actions you couldn’t help but be reminded of climate change and global warming today, which was a very sobering and grave thought.

This was an interesting documentary, I found out quite a lot from it, including some things about modern wildlife which I didn’t know. Professor Alice Roberts explained things clearly and concisely for people such as myself and I suspect most viewers who aren’t experts in the field of paleontology.

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