Long Necks Without Evolution

What do giraffes and sauropods have in common? A new paper shows how you can seek answers without Darwin’s help.

From an evolutionary perspective, sauropods (dinosaurs) and giraffes have almost nothing in common except being vertebrates and having long necks. Giraffes did not ‘evolve’ from sauropods, so it would be a remarkable ‘convergence’ to have these large beasts end up with similar neck vertebrae and the ability to lift and swing their heads on their magnificent necks. Call Darwin to help explain this, please!

A team of five led by Daniel Vidal apparently didn’t need Charlie’s help. There is nothing about evolution, convergence, mutation, selection or any other Darwinian concept in their open-access paper in PLoS One, titled “Ontogenetic similarities between giraffe and sauropod neck osteological mobility.” That’s ontogeny (development of the embryo to adult), not phylogeny (evolution) – no apologies to Haeckel. Instead, they consider just the facts: how these animals’ vertebrae possessed similarities and differences that allowed heavy lifting. The Abstract says,

The functional morphology of sauropod dinosaur long necks has been studied extensively, with virtual approaches yielding results that are difficult to obtain with actual fossils, due to their extreme fragility and size. However, analyses on virtual fossils have been questioned on several of their premises, such as the ability to accurately reconstruct intervertebral tissue with only skeletal data; or whether zygapophyseal [neck vertebrae parts] overlap can be used to determine the limits of range of motion, since some extreme neck poses in extant giraffes have been claimed not to retain any zygapophyseal overlap. We compared articulation and range of motion in extant giraffes with the exceptionally well-preserved and complete basally branching eusauropod Spinophorosaurus nigerensis from the Middle (?) Jurassic of Niger, under the same virtual paleontology protocols. We examined the articulation and range of motion on grown and young specimens of both Spinophorosaurus and giraffes in order to record any potential changes during ontogeny. Also, the postures of virtual giraffes were compared with previously published data from living animals in the wild. Our analyses show that: (i) articulation of virtual bones in osteologically neutral pose (ONP) does enable accurate prediction of the amount of inter-vertebral space in giraffes and, roughly, in Spinophorosaurus; (ii) even the most extreme neck postures attained by living giraffes in the wild do not require to disarticulate cervical vertebrae; (iii) both living giraffes and Spinophorosaurus have large intervertebral spaces between their cervical centra in early ontogenetical stages, which decrease as ontogeny advances; and (iv) that grown specimens have a greater osteological range of motion in living giraffes and Spinophorosaurus.

Maybe that’s not as exciting as a just-so story about ‘How the Sauropod Got Its Long Neck,’ but it qualifies as observable, measurable science. The authors begin with some pretty exciting facts, though, about the amazing necks of other dinosaurs.

The elongated neck of sauropod dinosaurs is one of their more notable features. These necks vary tremendously in length, both in relative and absolute terms: from the relatively short-necked Brachytrachelopan mesai, which has a one meter long neck representing less than a quarter of the length of its axial skeleton, to the up to nine meter neck of Mamenchisaurus sp., which accounts for approximately half the length of its axial skeleton. The number of cervical vertebrae in sauropods also varies, with a basal condition of likely 12 cervical vertebrae, present in most sauropods with complete necks. to up to 19 cervical vertebrae in Mamenchisaurus hochuanensis.

Nine meters, for English folk, is about 30 feet. Inside that long neck were not only the massive bones, but blood vessels, nerves, muscles and all the other requirements for connecting the head to the vital organs. It’s a huge engineering problem to be solved, because too big a strain would break the bones apart (disarticulate them). The giraffe is amazing enough, but the sauropod reached nearly double the giraffe’s reach, and would have required enormously more powerful construction, like a semitruck compared to a sedan. Did evolution solve these design constraints, or were these huge animals designed for their lifestyle with the necessary equipment to reach high into the air? The research team did not have to get into origins. Their focus was on facts of physics.

Adult and juvenile Spinophorosaurus, adult and juvenile giraffe, human for comparison. From Vidal et al., PLoS One, Fig. 1.

Correcting the Record

The authors point out that previous models are wrong. They call into question results from software called DinoMorph that concluded these huge dinosaurs were barely able to keep their heads level with the body. We know that living giraffes raise their heads high up into the tree tops. If that’s what sauropods needed to do to eat, why wouldn’t they be similarly equipped? This team shows a diagram of Spinophorosaurus with its head held high, like the giraffe. Scientists can observe giraffes moving their long necks easily in all directions, but that is not possible for dinosaurs. By comparing vertebrae of young and adult specimens of Spinophorosaurus and giraffes using software, they believe the dinosaur, like the giraffe, had a large range of motion – both vertically and horizontally. The bones and the spaces between them adjusted during growth to adulthood so that the animals never were lacking for flexibility. Jurassic Park was correct in its depiction of these huge beasts moving their heads up, down and sideways.

Credit: Illustra Media, Ode to the Animals

From a functional morphology point of view, the observed differences in posture and range of motion between newborn and adult giraffes are compatible with ethological differences observed in wild populations. Giraffes exhibit a wide range of behaviors regarding their necks in the wild. By comparing giraffe wild behavior and postures obtained with the osteological range of motion analyses, we can assess whether disarticulating vertebrae, the limits set for most osteological ROM [range of motion] analyses, is or not necessary to achieve certain extreme live postures. Whether in vivo range of motion may have been greater than the actual bone geometry suggests has tremendous implications for range of motion analyses in extinct taxa.

Comparing Engineering Designs

Look at a giraffe moving its neck; that gives you a pretty good approximation of what the sauropods could do, the scientists say. A giraffe can lick its torso. Imagine that engineering problem! And just like a newborn giraffe has no problem moving its neck as it grows multi-fold bigger, that was probably true of the sauropods, too. So indicate the fossilized bones by comparison.

All feeding postures reported in wild giraffes fall within the osteological range of motion for both the adult and newborn specimen….

While there is little information regarding the feeding ecology of sauropod dinosaurs, the range of motion of Spinophorosaurus potentially enabled them to browse at the same positions as giraffes.

This is a tremendous problem for evolution. How did the long neck and its development to adulthood become so finely-tuned in similar ways in two large animals that are not related? According to Darwin, all mammals evolved from small shrew-like mammals in the ‘age of dinosaurs.’ The giraffe would have to evolve this ability from scratch.

The authors point out that baby giraffes cannot reach down to drink. No problem. They breastfeed until the neck grows long enough. This means that timing of engineering constraints is a factor to be considered, too.

Exploding Heads

Creationists have enjoyed pointing out another problem: getting blood way up to the head when a giraffe reaches high, and preventing the brain from exploding when the giraffe reaches down to drink. Dr Jobe Martin explained in his film Incredible Creatures that Defy Evolution why Darwinian theory cannot explain that; the giraffe would faint whenever it lifted its head to escape a predator, and would have a stroke every time it stooped to drink. Giraffes have special vessels to keep blood from flowing down the arteries when the giraffe reaches up, and it has special spongy tissues to prevent brain explosions when drinking. They also instinctively splay their legs to get the head closer to the water. Unless all these specialized mechanisms existed together, no baby giraffes would ever be born.

The scientists could not infer how sauropods reached down to drink, but made educated guesses that they also splayed their legs to reach the ground or the water. They believe that sauropods were also gifted at moving their huge tails, even though giraffe tails are short and thin.

In their seven final conclusions, not once did the scientists refer to evolution. They apparently had no use for it, really. Maybe they avoided the engineering problems for Darwinian evolution on purpose, not wanting to speculate on how the Stuff Happens Law could account for the similarities. Conclusion #7, “Spinophorosaurus is the most basally branching sauropod to date to have evidence of capabilities for high browsing,” would not disturb creationists who, using baraminology theory, could accept some horizontal branching of species within limits of the sauropod kind.

The only ones whose heads might explode are Darwin dogmatists who insist that nothing in biology makes sense except in the light of evolution. Sorry, guys; Vidal et al. have no need of that hypothesis.

Behold, Behemoth,
    which I made as I made you;
    he eats grass like an ox.
Behold, his strength in his loins,
    and his power in the muscles of his belly.
He makes his tail stiff like a cedar;
    the sinews of his thighs are knit together.
His bones are tubes of bronze,
    his limbs like bars of iron.  –Job 40:15-18