Ankylosaurus

0-1 Tail Club

Hailing from the renowned **Hell Creek Formation** of **Late Cretaceous** North America, *Ankylosaurus* is the largest member of the thyreophoran dinosaurs—with rather exceptional individuals reaching 9 blocks long and weighing 10.5 metric tonnes—although most individuals are smaller, and in some cases may reach only 6 blocks and 3 tonnes.

It is a rare species throughout most of Hell Creek, but can commonly be found in the highlands of *Liriodendrites Bluffs*—avoiding ecological competition with *Triceratops*, which instead occupy the lowlands of the formation.

## Feeding

*Ankylosaurus* has a wide snout, perfect for a varied diet and non-selective browsing. Most commonly, they feed on abundant ferns and low-growing shrubs such as *Osmunda*, consuming up to 60 kilograms per day—though foraging on any available fruit may bring this requirement down, which its beak and small cusp-like teeth are well-adapted for, particularly in comparison to other members of Ankylosauria.

*Ankylosaurus* possesses an exceptional sense of smell, and due to the wide separation of the nostrils, each nostril can sense smells from a different direction. As *Ankylosaurus* has poor eyesight, it instead relies on this great ability to smell as its primary perception while foraging, locating potential meals wherever they may be. The retracted position of the nostrils is also rather useful during earth-moving, as debris are unable to enter them while *Ankylosaurus* uses the end of its wedge-shaped snout like a shovel—pushing dirt around to dig for roots and tubers.

Although predominantly herbivorous, certain invertebrates, which the small teeth are also suitable for handling, provide supplemental nutrition for *Ankylosaurus*—especially when in need of more protein. Its tongue is notably muscular and sticky, and is used to lick up insects as they flee from their dug-out tunnels.

## Defense

The tail club of *Ankylosaurus* is an active defensive weapon, capable of producing enough impact to break bone, including the leg bones of large theropods like *Tyrannosaurus*. The tendons of the tail are partially ossified and are very stiff, and several hindlimb muscles near the base control the swinging of the tail, allowing great force to be transmitted through the club when used in combat.

Unfortunately, while adult tail clubs are capable of breaking bones, those of juveniles are not—and due to their softer, less ossified plates of armor, juvenile *Ankylosaurus* are more likely to be targets of predation. Their cautious tendencies generally reflect this, being wary of any animal larger than themselves. Occasionally, a predator may be able to ambush a juvenile *Ankylosaurus* before it can clear enough distance, and may pierce the armor with a well-placed bite. If its attempt to flee fails, a juvenile may dig a shallow trench and lodge itself inside. Predators are seldom able to dislodge the animal once burrowed, and will abandon it if they cannot breach the armor.

## Social Behavior & Reproduction

As an adult, *Ankylosaurus* are solitary and do not congregate in groups—though to deter predation, the vulnerable juveniles do congregate with one another while still young, as there is safety in numbers.

Although territorial, male *Ankylosaurus* are not provoked by the presence of females within their territory. Males become aggressive only toward other males in order to keep them out—increasing their own chances of pairing with a female. If competition over a female occurs, the two males may employ their tail clubs to fight for the opportunity to mate with her—often aiming for the base of the other’s tail, as they are unable to fight back if their tail has been injured.

Adults meet only to mate, with mating typically taking place at dusk. Rather than the males seeking out females, males mark their territory with their scent, attracting any potential nearby mates toward them. While pairing, the male and female intermittently interact by sniffing one another, playfully waving their tails, and the female lifting hers. Once the female digs a deep hole in the substrate as a nest, the father will leave, and the mother may remain to protect the eggs—however like the father, she will not care for her young after they hatch, and will ultimately abandon them to fend for themselves.

## *Ancient Journal Entry*

*Day 17:*

*While roaming the forests of Hell Creek, I discovered the most peculiar animal. Upon further inspection, I have concluded that the beast is none other than an Ankylosaurus. Covered in armor, and equipped with it's large club tail, I believe that the Ankylosaurus is quite capable of standing it's own in a fight against even the mighty Tyrannosaurus. When I tried to get close to investigate a lone Ankylosaurus, it prepared to attack, unlike most other herbivores I've seen.*

*Day 21:*

*I've discovered that these magnificent animals love clubmoss! Upon feeding two Ankylosaurus this, they began to mate, and laid several eggs nearby.*

*Day 23:*

*I stumbled upon a dead Ankylosaurus yesterday, and an idea struck me. Would it's armor protect me as well as it does them? I set to work, and created a wonderfully protective chest plate and helmet!*