WWD: Diplodocus hallorum (Juvenile)
Added 2023-04-18 01:46:49 +0000 UTCBecause the immature form of Diplodocus features heavily in the episode, I'll also include this version in the parade to show how our perspective of sauropodlets has changed since the program's production.
The episode states that Diplodocus reached adult size within one decade, but this is possibly very overly optimistic, and it's well beyond the growth of any modern tetrapod scaled up; newer studies on sauropod growth rates suggest it may have taken several decades. Although of course it's hard to tell exactly how long it took; it could be anywhere from just over twenty to seventy years. The individual I've illustrated would correspond to an individual about four to six years old.
Another difference is the appearance of the juveniles. Far from the toddling, corgi-proportioned youngsters in the episode, Diplodocus sauropodlets were quite lanky and tall. Their legs were very long indeed relative to their body size when compared to adults. In fact, the length of the femur increased by less than 30 centimetres from a 20-foot long juvenile to an 85-foot long adult. What this suggests is not clear, but perhaps they could actually run from predators? It would certainly help explain just how these walking hamburgers managed to somehow survive to adulthood.
What the episode does get right is that juveniles had different dentition from adults and likely favoured more forested habitat than adults, relying on the cover of foliage for survival before their size could protect them. Their skulls were shorter and more triangular, but gradually lengthened and widened as they aged. Sauropodlets were also probably much less picky about their diet than adult Diplodocus; they couldn't afford to be picky when they needed to bulk up as fast as possible.
