Biome 08 of 10
Prehistoricbiome in Steal An Egg
A near 7x jump from Abyss Ocean. Mosasaurus at $180M/s is the payoff, and both T-Rex and Tralaledon are Secret-tier.
Multiple sources agree
Sources · checked 2026-08-27
- Speed required
- 17M
- Guardian
- T-Rex
- Pets
- 8
- Top earner
- $180M/s
All 8 Prehistoric pets
| Pet | Rarity | Income / sec | Share of biome total |
|---|---|---|---|
| Dodo | rare | $280 | 0.0% |
| Pterodactyl | legendary | $22K | 0.0% |
| Ankylosaurus | mythic | $120K | 0.1% |
| Triceratops | cosmic | $1.2M | 0.5% |
| Bronto | cosmic | $1.5M | 0.6% |
| T-Rex | secret | $25M | 10.4% |
| Tralaledon | secret | $32M | 13.3% |
| Mosasaurus | eternal | $180M | 75.0% |
One of each pet in this biome would earn $240M/s combined — though Mosasaurus alone accounts for 75% of that, which is the usual shape in this game: the top pet dominates its biome.
Rarity spread
- Rare×1
- Legendary×1
- Mythic×1
- Cosmic×2
- Secret×2
- Eternal×1
Getting here from Abyss Ocean
This is the concrete gap, not a vague “grind more”. Moving from Abyss Ocean to Prehistoric means finding 14.5M more Speed — a 6.8× increase on where you are standing.
- 1
Bank the best Abyss Ocean pet you can hold
That is El Maja at $130M/s. This is what funds the step — treadmill upgrades come out of pet income, so the gap closes at the rate your pen earns.
- 2
Put every dollar into the treadmill, then a trail
Treadmill upgrades add to your Speed per second; trails multiply it. Because the multiplier also applies to every upgrade you buy afterwards, a trail bought at the start of this step is worth more than the same money spent at the end of it.
- 3
Clear 17M, then keep going to 42.5M
The requirement opens the door. The extra margin is what gets you back out carrying something heavy. Stopping at the floor is the single most common way players lose runs.
- ✓
What you are actually here for
Mosasaurus at $180M/s, which is 1× what the best Abyss Ocean pet earns. That multiple is why the grind is worth it, and why players who stall in one biome stay stalled.
Put your current Speed and treadmill rate in the planner → to turn this into an actual number of hours.
The T-Rex
The T-Rex is both a guardian and, separately, a Secret-rarity pet you can hatch. Being chased by the thing you are trying to collect is the joke of this biome, and it is not a slow one.
Guardian behaviour is a player observation rather than a published figure, so this is written as commentary, not data. It carries no sourcing badge because there is no source to cite — if your experience differs, tell us.
How big a jump is this?
Prehistoric asks for roughly 6.8× the Speed that Abyss Ocean does — 2.5M up to 17M. That is a normal step in the progression curve — keep reinvesting pet income into treadmill upgrades and it arrives on its own.
Prehistoric FAQ
What Speed do you need for Prehistoric in Steal An Egg?
17M Speed to enter. That is the entry floor — aim for around 42.5M before carrying an egg out.
What is the Prehistoric guardian?
The T-Rex. Meeting the minimum Speed does not mean you can outrun it, especially while slowed by a large egg.
What is the best pet in Prehistoric?
Mosasaurus, a eternal pet earning $180M per second before mutations.
How much harder is Prehistoric than Abyss Ocean?
Prehistoric asks for roughly 6.8× the Speed that Abyss Ocean does — 2.5M up to 17M.