Biome 8 of 13
Prehistoric Biome
Route position
8 / 13
After Abyss Ocean
Speed needed
18M
×7.2 vs Abyss Ocean
Pets
8
Top rarity: Eternal
Income range
$180M/s
from $280/s
Guardian
T-Rex
It sleeps next to the Prehistoric nests. You need 18M Speed to enter this biome and get away with an egg.
Prehistoric pets by income
| Pet | Rarity | Egg | Grow time | Reward | Income |
|---|---|---|---|---|---|
| Eternal |  Mosasaurus Egg | 6h | +600k Speed, $18b | $180M/s |
| Secret |  Tralaledon Egg | 3h | +480k Speed, $3.2b | $32M/s |
| Secret |  T-Rex Egg | 2h 30m | +420k Speed, $2.5b | $25M/s |
| Cosmic |  Bronto Egg | 11m | +300k Speed, $150m | $1.5M/s |
| Cosmic |  Triceratops Egg | 8m | +360k Speed, $120m | $1.2M/s |
| Mythic |  Ankylosaurus Egg | 5m | +330k Speed, $12m | $120K/s |
| Legendary |  Pterodactyl Egg | 3m | +270k Speed, $2.2m | $22K/s |
| Rare |  Dodo Egg | 1m 30s | +240k Speed, $28k | $280/s |
Prehistoric guide
Dinosaurs fill the eighth biome. Prehistoric opens at 18M Speed, and its guardian is the T-Rex, a Secret worth $25M/s that also hatches from one of the biome's own eggs after 2 hours 30 minutes.
Two Secrets, two Cosmics and the Mosasaurus
- Dodo (Rare, $280/s, 1m 30s, +240k Speed), the highest-earning Rare in the game.
- Pterodactyl (Legendary, $22K/s, 3m, +270k).
- Ankylosaurus (Mythic, $120K/s, 5m, +330k).
- Triceratops ($1.2M/s, 8m, +360k) and Bronto ($1.5M/s, 11m, +300k), both Cosmic.
- T-Rex ($25M/s, 2h 30m, +420k) and Tralaledon ($32M/s, 3h, +480k), both Secret.
- Mosasaurus (Eternal, $180M/s, 6h, +600k).
The Bronto is the odd one: it earns 25% more than the Triceratops but takes three minutes longer and pays less Speed (+300k against +360k), even less than the Mythic Ankylosaurus. Mosasaurus is the biome's best earner, fifth of the 24 Eternals.
The steepest wall so far
Cosmic requires 700M Speed, about 39 times Prehistoric's entry requirement. That leaves a 682M gap, while one of every Prehistoric egg adds 3M. Even the Dodo, which returns about 2,667 Speed per second of growth, would need around 2,842 eggs to close it alone.
The practical answer is multipliers. The wiki's lists put the Galaxy Trail (5×) at $20B and The Freeze Treadmill (+100 per step) at $3B. One Mosasaurus reward ($18b) nearly covers the Galaxy Trail; one Tralaledon reward ($3.2b) pays for the treadmill. The shop also sells Speed multipliers for Robux, from x2 at 3 Robux up to x4K at 1375 Robux.
Riftbeasts and Shattered Rift
Prehistoric is the first biome shared by the Riftbeasts and Shattered Rift banners. Its pets on the Rift Sacrifice tiers:
- Easy: Dodo and Pterodactyl.
- Medium: Ankylosaurus.
- Hard: Triceratops and Bronto.
T-Rex, Tralaledon and Mosasaurus are not on the lists, so the Cosmics are the most valuable spares to hold for a Hard request.
Rift banners with these eggs
The permanent Rift rotates between egg pools, and each pool draws from a set of biomes. Prehistoric eggs appear in:
- RiftbeastsVolcano · Abyss Ocean · Prehistoric · Cosmic
- Shattered RiftPrehistoric · Cosmic · Cherry Blossom · Titan Temple
Related guides
How to Get Speed Fast in Steal an Egg: Every Method
Every way to raise Speed in Steal an Egg with real numbers: the 10,000 Speed gift, all treadmills and trails, the best Speed eggs, Robux multipliers…
Steal an Egg Enchanted Forest: Wisp, Enchanted Tree and 50B Speed
Everything Update 7 confirms about the Enchanted Forest, the Wisp quest and the 100% Enchanted Mutation, plus a data-based plan to climb from 20B to…
Data sourced from the Steal an Egg Wiki (CC BY-SA) and processed automatically; last synced 2026-10-11.