The wildlife of Yellowstone National Park comes into both the big and small categories.
And big means big – Yellowstone’s species include bison, North America’s largest mammal with males weighing in at almost a tonne.
At the last count, there were more than 5,000 in the park, the only place in the USA where they have lived continuously since humans first reach the Americas.
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There is the grizzly bear (a subspecies of the brown bear, which is also found in Europe and Asia), a large and potentially aggressive carnivore that can weigh more than 300kg.
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- It weighs as much as a car, can sprint at 30mph, has dinner-plate paws armed with 3in claws – and jaws powerful enough to crush a human skull like an egg
Throw in moose, elk (a very close relative of Eurasian red deer), black bears and wolves, and you’ve got an all-star cast of charismatic megafauna which makes Yellowstone indisputably one of the top wildlife attractions anywhere in the world.
And then there’s the small stuff. And small means small – and weird, too.
Take Norris Geyser Basin, an area – like so much of the park – of hydrothermal activity that is the visible expression of the immense and very active volcano that lies beneath the surface.
Here, the super hot, acidic water is home to extremophiles, singled-celled creatures that thrive on chemicals such as sulphur. There are bacteria and archaea – organisms that are placed on a completely different branch of life to everything considered to be an animal – here that metabolise iron in water just below 60˚C.
- Something breathtaking has just been pulled from the steaming springs of Yellowstone National Park
- “The first thing to go are the eyes. Eyes, apparently, cook very quickly. Flesh follows soon after, and as the animal becomes overwhelmed, water enters its mouth."
The rich yellow and reddy-brown colours that are so spectacular at Norris and the many other hydrothermal sites are evidence of these remarkable organisms. You’ll also see emerald-green mats which are algae that also thrive in this severe environment.
It’s speculated that some of the very earliest life forms that evolved on Earth did so in similarly hot and acidic conditions, so a visit to Yellowstone like going back billions of years in time.
And all that without even mentioning arguably Yellowstone’s most famous resident – Old Faithful, a geyser that erupts on average every 92 minutes and can reach a height of 55 metres, which would see super-heated water shooting over Nelson’s Column were it situated in Trafalgar Square.
Yellowstone is undoubtedly one of those places where you need to take care that you don’t surprise any of its black or brown bears, or even, come to that, its moose or bison and that you don’t take a swim, either deliberately or accidentally, in its thermal, acidic pools.
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- “I found myself standing shoulder-to-shoulder with a huge male grizzly bear.”
Sometimes it’s said the greatest danger is the Yellowstone volcano itself, which is overdue an eruption. Happily, this is one risk you don’t need to worry about – the US Geological Service says it is misleading or arguably untrue. All we know is that it has erupted three times – 2.1, 1.3 and 0.64 millions years ago, and this doesn’t provide enough evidence for when it will go again. Enjoy your visit.
