Dinosaur, Edmontosaurus, The Titan of the Floodplains
“The giant duck-billed dinosaur that thrived in massive herds and survived deadly predator onslaughts—discover the Edmontosaurus!”
The Edmontosaurus is a massive herbivore, stretching up to 40 feet long with a broad, flat duck-billed snout perfect for cropping vast amounts of vegetation. Its body is robust and heavily muscled, supported by strong hind legs and a long, balancing tail. Its skin is typically rough and scaly, often depicted with muted earth tones or subtle striping that aids camouflage in dense forests and floodplains.
Behaviour
Edmontosaurus is a highly social creature, moving in large herds that can number in the dozens or even hundreds. These herds provide protection against predators and facilitate cooperative migration to seasonal feeding grounds. When threatened, Edmontosaurus relies on the herd’s vigilance, emitting loud warning calls and moving collectively to deter or outrun attackers.
Habitat
Edmontosaurus inhabits vast floodplains, river valleys, and coastal forests, thriving in areas rich with ferns, conifers, and flowering plants. It favors regions with abundant water sources and dense vegetation, which sustain its large appetite and provide shelter for its young.
Modus Operandi
As a herbivore, Edmontosaurus spends much of its day grazing, using its broad beak to strip leaves, twigs, and aquatic plants. When confronted by predators, it attempts to flee with powerful strides or seeks safety within the herd’s protective circle. In desperate situations, it can deliver powerful tail swings or kick with its hind legs to defend itself.
Motivation
Driven primarily by survival and reproduction, Edmontosaurus seeks safety in numbers, ensuring the continuation of the herd. It aggressively protects its young and territory during the mating season. Though non-aggressive by nature, starvation or extreme threat can provoke fierce defensive actions.
Edmontosaurus 5e
Edmontosaurus 3.5
Edmontosaurus
Huge Beast, Unaligned
Challenge: 5 (1,800 XP)
Proficiency Bonus: +3
Armor Class 13 (natural armor)
Hit Points 136 (13d12 + 52)
Speed 40 ft.
STR | DEX | CON | INT | WIS | CHA |
---|---|---|---|---|---|
20 (+5) | 11 (+0) | 18 (+4) | 2 (–4) | 14 (+2) | 8 (–1) |
Saving Throws Constitution +7, Wisdom +5
Skills Perception +5
Senses passive Perception 15
Languages —
Traits
Herd Instincts.
The Edmontosaurus has advantage on Wisdom (Perception) checks and saving throws against being frightened if at least one ally is within 30 feet.
Trampling Charge.
If the Edmontosaurus moves at least 20 feet straight toward a creature and then hits it with a Charge Slam attack on the same turn, the target must succeed on a DC 15 Strength saving throw or be knocked prone. If the target is prone, the Edmontosaurus can make one tail slam attack against it as a bonus action.
Aquatic Grazer.
The Edmontosaurus can hold its breath for 15 minutes and can move through water at half its walking speed without penalty.
Actions
Multiattack.
The Edmontosaurus makes two attacks: one with its Charge Slam and one with its tail slam.
Charge Slam.
Melee Weapon Attack: +8 to hit, reach 10 ft., one target.
Hit: 18 (3d8 + 5) bludgeoning damage. If the Edmontosaurus moved at least 20 feet straight toward the target before hitting, the target must succeed on a DC 15 Strength saving throw or be knocked prone.
Tail Slam.
Melee Weapon Attack: +8 to hit, reach 15 ft., one target.
Hit: 21 (3d10 + 5) bludgeoning damage.
Herd Stampede (Recharge 5–6).
The Edmontosaurus calls upon nearby herd members and charges forward in a massive stampede. Each creature in a 30-foot-wide, 60-foot-long line must succeed on a DC 15 Dexterity saving throw or take 27 (6d8) bludgeoning damage and be knocked prone. On a successful save, creatures take half damage and aren’t knocked prone.
Tactics
- Stays close to allies to leverage Herd Instincts for greater resilience.
- Uses Trampling Charge to knock down foes and follows up with tail attacks.
- Employs Herd Stampede to break enemy lines in open terrain.
- Defends itself strongly if isolated, relying on reach and powerful body slams.
Environment
Floodplains, river valleys, and lush forests, often near water.
Treasure
None. However, its hide and bones are valuable for crafting primitive armor and weapons.
Edmontosaurus

Originally Posted by Insane Pixie of the Wizards Community forums.
On this Thread
Closely related to the saurolophus, these duck-billed herbivores stand about 16 feet tall, measure 43 feet long, and weigh approximately 3 tons.
Edmontosaurus | |
Huge animal | |
Hit Dice | 19d8+205 (295 hp) |
Initiative | +0 |
Speed | 30 ft. (0 squares) |
Armor Class | 18 (-2 size, +10 natural), touch 8, flat-footed 18 |
Base Attack/Grapple | +14/+30 |
Attack | Slam +20 melee (1d8+12) |
Full Attack | Slam +20 melee (1d8+12) |
Space/Reach | 15 ft./10 ft. |
Special Attacks | Trample 1d12+12 |
Special Qualities | Low-light, Scent |
Saves | Fort +11, Ref +6, Will +9 |
Abilities | Strength 27, Dexterity 10, Constitution 31, Intelligence 1, Wisdom 12, Charisma 10 |
Skills | Listen +16, Spot +16 |
Feats | Iron Will, Improved Natural Attack (Slam), Toughness (5) |
Climate/Terrain | Temperate plains |
Organization | Solitary, pair, or herd (20-40) |
Challenge Rating | 10 |
Treasure | None |
Alignment | Always neutral |
Advancement | 20-26 HD (Huge) |
Level Adjustment | – |
Combat
Trample (Ex) Reflex half DC 26. The save DC is Strength-based.
Skills A edmontosaurus has a +4 racial bonus on Listen and Spot checks.