The giant Brachiosaurus
Brachiosaurus was a genus of sauropod dinosaur that roamed the Earth during the Late Jurassic period (circa 155-140 million years ago). They are characterised, like many sauropods of the time, by their huge necks and comparatively tiny skulls and brains. Currently only one species has been officially confirmed – B altithorax – though others have been suggested.
Interestingly, like other sauropods, these creatures – despite weighing an estimated 60 tons and measuring up to 30 metres (98 feet) long – were actually colossal vegetarians, with their diet comprising solely foliage.
Their evolution of such a long neck (see ‘The high life’ boxout for more details) seems to be intrinsically linked to their diet, with the elevated head position enabling them to access leaves unavailable to shorter species.
This dominion over a food source is also a major factor behind their generally massive proportions, with millions of years of domination allowing them to grow to sizes far in excess of rival creatures from the same era.
The epic size of Brachiosaurus was also its primary form of defence when it came to predators. Once fully grown, their legs would have resembled tree trunks and these – partnered with a heavy, stocky tail – made them extremely difficult to tackle.
While their size and domination granted many benefits, it was also a contributor to Brachiosaurus’s eventual demise, with resource depletion and climate change leading to their background extinction around 145 million years ago.