Alaskan Troodontid

## Alaskan TroodontidIndeterminate species

***“ Most animals flee from the flames. But for some, the disaster creates opportunities. This six foot-long dinosaur, a troodontid, is one of the smaller members of the theropod group. ”***

― **David Attenborough**, *Ice Worlds*
Present on Prehistoric Planet is an **unnamed troodontid** that lived somewhere in the Arctic Circle. It most likely resided in the Prince Creek Formation, Alaska, USA, 71 - 69 million years ago, during the Maastrichtian stage of the Late Cretaceous Period.

According to Dr. Darren Naish, Prehistoric Planet's lead consultant, the show originally considered calling it *Troodon*, *Stenonychosaurus*, or *Latenivenatrix*. Unfortunately, each name is associated with problems. The validity of *Troodon* has been called into question since 2011, and the debate regarding that continues to this day. *Latenivenatrix* may be a junior synonym of *Stenonychosaurus*, and even if it were distinct, as the largest known troodontid, *Latenivenatrix* has a 3.5-meter (11-foot) body length, twice that of this unnamed troodontid. Lastly, even if all three species were equally valid, they all lived in the Campanian stage of the Late Cretaceous, around 77 - 75 million years ago, at least 3 - 5 million years before the show's Maastrichtian time scope. Hence, it is understandable that the species ultimately went unnamed in the show.

## Description

### Size and Physique

While unlikely to be *Stenonychosaurus* due to the unnamed troodontid having lived further up north and later in time, *Stenonychosaurus* closely matches the features of this species, with a height of 1.22 meters (4 feet), a body length of 2.5 meters (8 feet, 3 inches), and a weight of 35 kilograms (77 pounds), making it slightly larger than this six-foot Alaskan troodontid.

It should be noted that Prince Creek is also home to still-unnamed troodontids that make up two-thirds of all fossils in the area (as opposed to other areas, where troodontids only made up 6% of the native fauna). These troodontids are almost twice as big as their cousins in Alberta and Montana, equivalent to the size of *Latenivenatrix*. However, since the Alaskan troodontids of Prehistoric Planet are stated to be only six feet in length, the show might not have intended it to be a portrayal of the large troodontid species (unless they are intended to be juvenile forms, though this is unlikely).

Nevertheless, like all troodontids, this unnamed species is slightly smaller and more gracile than its more robust relatives, the dromaeosaurs, with a smaller sickle claw that is not as significantly recurved.

### Dentition

The type species of the family of this unnamed animal, *Troodon* (Wounding Tooth), is named for prominent serrations on its teeth, with wear patterns indicating that they were best suited for soft-bodied prey like early mammals. However, there were also suggestions that these serrations actually resembled those seen on the teeth of herbivorous reptiles, leading to theories about troodontids being omnivores.

### Brain and Senses

***“ Its huge eyes give it acute sight, even in the smoky gloom. And for its size, its brain is one of the largest on the planet. It is the most intelligent, adaptable, and successful hunter in the Arctic. ”***

― **David Attenborough**, *Ice Worlds*
As maniraptorans, troodontids are known for their large eyes (which faced forward to provide powerful binocular vision) and large brains, hence, they are often stated to be the smartest non-avian dinosaurs. Some troodontids even possess an asymmetric ear arrangement seen in some owls, with one ear higher than the other, allowing them to pinpoint sounds with more accuracy.

### Prehistoric Planet's Depiction

Prehistoric Planet depicts the Alaskan troodontid with mostly-gray plumage, with a black coloration covering the top of its head (save for white eyebrows) and wing feathers, and a whitish-gray underside and legs, providing the animal some countershading. It also possesses a pygostyle (tail fan), a bare gray snout, and black feathers on the back of its head, which occasionally flare out, much like the ornamental head feathers of some modern birds.

Much like *Atrociraptor*, *Dromaeosaurus*, and *Imperobator*, this Alaskan troodontid is depicted with legs that are heavily-feathered like those of a booted eagle, in contrast with other paravians in the series like *Velociraptor*, which have bare legs. This trait is likely an adaptation for the cold environment it lived in, or, conversely, the heat of the forest fires that frequently occur in the region during summer.

## Habitat

*Main: Prince Creek Formation*

Main: Prince Creek Formation

***“ Although the short and warm polar summer is a time of great plenty, it can also bring perils. Warm air rises and becomes charged electrically. And that creates frequent and violent lightning storms. In the north of America, the lush growth, fueled by the constant sunlight, has now been baked tinder-dry. ”***

― **David Attenborough**, *Ice Worlds*
This troodontid is stated to live within the Arctic Circle. While it isn't the large troodontid of Alaska, it is likely that it did live 71 - 69 million years ago in the Prince Creek Formation, a polar woodland that experienced 120 days of winter darkness, with temperatures dropping as low as 2 - 4 degrees Celsius (36 - 39 degrees Fahrenheit) during the cold months. Even so, the warm conditions of summertime are not devoid of danger, and may in fact start lightning storms and cause the area to suffer frequent forest fires.

## Behavior

***“ At the fire's edge, troodontids gather to prey on animals that are trying to escape the flames. Anything that spreads the fire creates more opportunities for the most ingenious Arctic hunter of its time. ”***

― **David Attenborough**, *Ice Worlds*
Due to their large brains giving them high intelligence, troodontids may have used tactics similar to those of birds of prey today. Based on behaviors of modern-day lizards, birds, and even crocodilians, the troodontids using burning twigs as tools to deliberately spread fires to flush out prey in Ice Worlds may not be as far-fetched as it first appears.

## Appearances

### Ice Worlds

In the fourth segment of the episode, a lightning storm, formed by the warm summer conditions, sets a forest in the Arctic ablaze. One troodontid, slowly walking in the midst of the flames, tries to pinpoint the source of the sounds it hears, the calls of distress of other animals. It stalks around the forest, waiting for some of these other creatures to flee the flames and run straight into it. Eventually, the troodontid comes across a stick, smoking embers on its tip. Realizing what it can do with this, the troodontid runs off with the burning twig in its mouth, eventually dropping it by a tree that still seems unaffected by the flames.

With this action, the forest fire spreads, and several *Cimolodons* rush out of the woods, right where the troodontid is waiting to ambush and pursue them. The theropod eventually grabs one of the multituberculates with its jaws, pinning it to the ground while shaking its neck, snapping it in the process. Its hunt a success, the predator gets up, holding the limp body of its latest kill by the neck, shaking it one last time before letting loose a single chirp of satisfaction, slightly flaring out the feathers on the back of its head.

## References

### General

1. ↑ A New Troodontid Theropod, *Talos sampsoni* gen. et sp. nov., from the Upper Cretaceous Western Interior Basin of North America
2. ↑ Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation
3. ↑ 3.0 3.1 The giant troodontid dinosaurs of Alaska
4. ↑ Fiorillo, Anthony R. (2008) "On the Occurrence of Exceptionally Large Teeth of *Troodon* (Dinosauria: Saurischia) from the Late Cretaceous of Northern Alaska" Palaios volume 23 pp.322-328
5. ↑ Holtz, Thomas R., Brinkman, Daniel L., Chandler, Christine L. (1998) Denticle Morphometrics and a Possibly Omnivorous Feeding Habit for the Theropod Dinosaur *Troodon*. Gaia number 15. December 1998. pp. 159-166.

### Dr. Darren Naish

1. ↑ The names *Troodon*, *Stenonychosaurus*, and *Latenivenatrix* were considered for the Alaskan Troodontid, though it was ultimately referred to by just its group name on Prehistoric Planet.
2. ↑ The concept of troodontids deliberately spreading fire is based on how modern-day predatory birds spread forest fires to flush out prey. While it is yet to be confirmed whether troodontids were similar to modern-day predatory birds in terms of cognitive abilities and behavioral flexibility, it is reasonable given the the surprisingly flexible and innovative ways of modern lizards, birds, and crocodilians.