Polacanthus Description
Polacanthus is an extinct genus of early armored, quadrupedal herbivorous ankylosaurian dinosaur that roamed early Cretaceous Europe. Characterized by its heavily armored body, this low-slung, bulky creature featured a broad torso supported by sturdy limbs. Its most defining physical trait was its extensive natural armor, which consisted of a mosaic of smaller bony osteoderms, bilateral rows of prominent spikes along its back and flanks, and distinctive shoulder or neck spines used for defense against predators. Additionally, it possessed a unique, reinforced “pelvic shield” composed of a large, flat, fused layer of bone with osteoderms covering its hip region. Because fossil remains of this dinosaur are incomplete and primarily consist of its rear half, its skull and front limbs remain poorly known to science, though reconstructions generally depict it with a small, beaked snout adapted for cropping low vegetation like ferns and cycads.
Could You Outrun a Polacanthus?
Yes, you could likely outrun a Polacanthus. Scientists estimate that this heavily armored dinosaur had a lumbering top speed of only around 9 mph (14.5 km/h). Since a healthy human can sprint between 12 to 15 mph in short bursts, you would easily leave this slow-moving herbivore in the dust.
Are You Bigger Than a Polacanthus?
No, you are not bigger than a Polacanthus! While it was low-slung and only stood about 3.3 to 5 feet (1 to 1.5 meters) tall at the hips, it was incredibly bulky. A mature adult grew up to 13 to 16 feet (4 to 5 meters) long—roughly the length of a small car—and weighed between 1 to 2 tons (2,200 to 4,400 lbs).
Fun Facts
- Its name translates to “many spines” or “many thorns” in Ancient Greek.
- It featured a unique “sacral shield” (pelvic shield), which was a solid sheet of completely fused bone protecting its lower back and hips.
- Unlike its later, more famous relative, the Ankylosaurus, Polacanthus completely lacked a heavy club at the end of its tail.
- The first fossil remains were discovered in 1865 by Reverend William Fox on the Isle of Wight, England.
Dino-mite Equations!
Question #1: A single Polacanthus measures roughly 5 meters long. If a modern compact car measures 4 meters long, how much longer is a line of 3 head-to-tail Polacanthus compared to a line of 3 parked compact cars?
Answer #1
3 m!
Question #2: An adult Polacanthus can weigh up to 2 tons (4,000 lbs). If a single large defensive fossil spike weighs an average of 5 lbs, how many spikes would it take to equal the total weight of one Polacanthus?
Answer #2
800 spikes!
