Paleo-Turtorials: The Memetic Bald-Headed Teratorn

So for any of you out there who has seen my latest deviation, you might be wondering what it is....until someone commented the right answer...in which case its a Merriam's Teratorn. 

Guess the Borb

While I'm at it, I just want to address a paleo-art meme that is sweeping the Paleocommunity for years, and that's the Old World Vulture Headed Teratorn.

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While it may seem like it would be appropriate to give a teratorn a old world vulture head, the evidence doesn't seem to stack up. For one, Teratorns are more closely related to New World Vultures, which means if they did have bald heads, they would look like New World Vultures, not the totally unrelated Old World Vultures. This is shown by THE AMAZING Julio Lacerda's drawing of a Argentavis.

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Secondly, from what we know of teratorns, we probably shouldn't even be giving them bald heads like Old World Vultures or even New World Vultures (Sorry Julio). Why exactly? Well I'll explain it too you.

1. Their Lifestyles are COMPLETELY different from their cousins
New World Vultures fly high in the sky to look for dead animals on the ground. Sure they may do some hunting here and there (and may I say, it is gruesome) and some species have even been known to eat plants from time to time, but for the most part, they are scavengers that fly high in the sky. Teratorns? COMPLETE OPPOSITE. They find their food by foot and they are much more active predators than the rest of their family. They hunt down small prey by stomping it with their powerful legs, and they may on occasion take down larger prey with their beaks and claws. While it may sound like there are no modern analogues to the Teratorns, there is one group of carnivorous birds that does the exact same thing. I'm of course talking about the amazing, the awesome, and the savage caracaras.

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Everything about the caracara's lifestyle matches perfectly with the Teratorns. They hunt mostly on the ground for small animals and kill them by stomping on them or killing them with their beak. Some young caracaras do take down larger prey in gangs where they attack using their beak and their claws to kill the animal they intend to eat. From what we know, Teratorns hunted on open grasslands such as the plains of the Andes and the American prairies. Some caracaras hunt in the same habitats, so it would reasonable that Teratorns behaved much like caracaras alive today. Since Teratorns weren't flying as much as their New World Vulture relatives, they didn't need to loose a feathered head (Vultures have bald heads because of thermoregulation. Since they spend so much time flying high up into the sky, they experience drastic temperature changes, so over the course of millions of years, most members of the two groups of scavenging birds lost most of the feathers on their head to counter this problem).

2. The Anatomy is not like that of a New World Vulture
New World Vultures have long, thin toes with small claws. These aren't very useful for hunting, but then again, New World Vultures don't hunt for most of the time.

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Teratorns are different. They have much shorter toes and larger claws. These are traits more suited to taking down fairly large prey, and they can be found in modern day eagles, owls, and of course, caracaras.

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Another thing that is striking about the features of Teratorns are their skulls. They have much taller skulls than their modern New World Vulture relatives, and it isn't seen in any living eagle or caracara. However, there is one bird that does have a skull similar to Teratorns: The Haast's Eagle.
The Haast's Eagle as we all know, is a predator of large prey, and it can take down that prey thanks to its massive claws. Its head however is interesting, since it looks very much like that of a Teratorn, it would stand to reason that both of them would be processing meat in a very similar way, suggesting they had similar external features.

3. Let's Talk about Where They Lived
From what we know, Teratorns were living in some pretty cold places. Argentavis for example was living on the cold, highland plains of Argentina. Teratornis lived in temperate forests and grasslands that would have gotten pretty cold during the winter. Since these animals wouldn't have been flying most of the time to look for food, they would need a coating of feathers to prevent them from losing body heat. The Mountain Caracara lives high up in the Andes, and has a coating of feathers on most of its face. Seeing as how Teratorns like Teratornis were living as far north as Oregon (which today get snow regularly during the winter. Imagine what it would have been like in the Ice Age), it would make sense that they would need a coat of feathers to protect them from the cold. Even California and Florida were relatively much colder than they are today, with forests and grasslands similar to the American prairie or the temperate forests of the east. Most New World Vultures (with the exception of the Andean Condor) live in much warmer places, such as rainforests, swamps, and dry grasslands. These places stayed much warmer than the places that the Teratorns lived in even during the Ice Age.

4. The Conclusion
All in all, it would seem that most of the depictions of Teratorns we see today are most likely not what the animals looked like in life. Not only are they different anatomically from their closest cousins, but they most likely behaved differently and lived in vastly different habitats. It would be more reasonable to depict Teratorns not as Vast Vultures, but as Colossal Caracaras*. After all, Teratorns share more in common with them than they do with their closest cousins. They both hunt mostly on the ground, live in open and temperate ares, and kill small prey by using their beak and their feet. They also share some similarities with other carnivorous birds, like the Haast's Eagle, in which both have a similar skull design. Teratorns are most likely far more different than we depict them as. I'm not saying that the bald headed idea is impossible, but it holds much less water than we think.

*Not to be confused with actual Giant Caracaras that roamed South America up until the Late Pleistoscene.

Thank you for reading this edition of my Paleo-Turtorial Series. Next episode of WWK will come out soon (and it will feature Teratorns), and maybe some more Paleo-Turtorials.