- The stream is almost halfway! Watch together with the dev in 2 hours - 30 June 2026
As you might know, at the moment I'm running a long livestream, simulating evolution 24/7. It's all epxplained in this video: We've been able to follow the planet Wright-2b for almost a week now, and the moving continent (named 'Rupert' by the community) is about halfway its journey. Many interesting things are happening, like: The two main continents are each hosting their own plant family: the western one is mostly red, the eastern one is mostly blue. The ocean was covered in floating algae for days, until the animals evolved eggs that could handle stronger ocean currents, which caused a huge boom in filter feeders, causing all algae to go extinct. The ecoystem on the larger continent (named 'Deus Agriculturae' by the community) is mostly based around fruit and fruit eaters. To celebrate making it until here I (the dev Wessel Stoop) will be present in the chat tonight at 1900h UTC (21…
- Wright-2b is live! - 25 June 2026
Streaming evolution simulation indie game The Sapling, 24/7 for 2 weeks: We started on planet Wright-2b with a simple alga and underwater animal, turned on random mutations, and now we watch what evolves. Introduction to the project:Introduction to the world:
- Patch v13.71 - 16 May 2026
Balancing and fixes for animals Various legs besides the body now have special requirements for the animal to have more than 1 set of limbs, to make them look more natural (already in the previous patch logs, but now it's working) Sessile animals with moving juveniles now actually move to the ocean floor and stop moving as adults (thanks, Cody Beaver, Cringus Ringus, Spectator, Acarlis, mic biology!) Idem for ocean floor walkers (thanks, Ancient Relic!) Optimized species population size tracker in situations with many species Balancing and fixes for plants Grass is now removed from a cell when eaten (thanks, esportfrank!) Wildfire now removes grass, and grass won't be able to grow there for a while Plant subspecies will now always have the same color as their parent species, to make it easier to identify which plant is which species Tweaked the chance of algae evolving into plants Worki…
- Patch v13.57 - 7 April 2026
Balancing and fixes for plants Major rebalancing of leaf statistics, so you will more variety in the leaves evolving Bioluminescent flowers and fruits now cost slightly more energy (thanks, Warlord-vir!) Prevented plants slowly taking over areas where they shouldn't be able to survive because of the moisture Prevented another way to make illegal fruits, causing the game to glitch (thanks, Svelyrai!) Balancing and fixes for animals Added a simple balance system to prevent animals that look like they will fall over from evolving Various legs besides the body now have special requirements for the animal to have more than 1 set of limbs, to make them look more natural Animals with various arthropod legs can no longer accidentally swim underwater (thanks, Abel Pérez Pastor!) Animals with only gasbags and no other limbs are no longer considered valid in the editor (thanks, Kaanaykas!) Noise p…
- Patch v13.52 - 17 March 2026
Working on land animal evolution Made the evolution of land animals more likely Animals with aquatic eggs that can only walk very slowly are now considered land animals if they also swim very slowly If there are only very few land species, subspecies branch off into their own species earlier Visualization: only reuse a model for an existing species if the subspecies has the same limbs. If not, a more accurate model will be used, but it will be recolored to match the original species color so you can quickly spot what animals are what species. Other changes to the simulation Animals no longer reproduce if they have a lot of neighbors, preventing extremely crowded simulations Fixed a grass mutation bug that could cause green areas without a visible grass (thanks, Azul1462!) Improvements for the cladogram The simulation in the background now pauses if you open the cladogram, and resumes ag…
- Patch v13.49 - 7 March 2026
More work on the project to make the game easier to understand Added a habitat map for the plant and animal editors, so you can quickly see where in your world this planet will survive Moved the 'this organism has a problem' message out of the editor side bar for editors, so it has more space for a more detailed explanation For the plant editor, merged the energy usage and energy profit bars into a single colored energy bar For the plant editor, made the 'amount of offspring' visualization textual For the planet editor, changed the season and ring toggles in the planet editor to have icons Added stretched arrow buttons to tutorial Redesigned the ready/discard buttons in all editors The alga and fungus editors now also have a discard button Moved the 'discard' buttons next to the ready button for every editor The 'ready' buttons are now recolored to fit the style of each individual edito…
- Patch v13.46 - 24 February 2026
A completely new cladogram view I've replaced the old cladogram view, because playtesting quite consistently showed that nobody was using it. The game is now using a completely new chronogram approach as can be seen in both Species ALRE and The Bibites. It should give a much better 'zoomed out' overview of which species branched off from which one at what point in time. Even though previous changes to speciation drastically reduced the number of species, the trees in this new cladogram/chronogram can grow quite large, so this view has been heavily optimized. Perhaps surprisingly, by far the hardest part were the resizable scrollbars that allow you to navigate large trees. I believe most issues have been fixed, but they sometimes still revert (making the view go left instead of right) for reasons I do not understand yet. UI mutation fixes Fixed the animal mutation view no longer always s…
- Patch v13.45 - 14 February 2026
Major simulation change If an animal is in a location that contains food, it will no longer leave that location until all food is gone (except plankton, which requires swimming through). This makes it a lot easier to keep various animals alive, addressing a recurring complaint... but also leads to crowded environment (and, following that, possibly low FPS) more quickly. Thanks Luka159, Generaldisblief, Wind_kaffee! Various changes to make the simulation easier to understand When placing down organisms, a minimalist version of the requirements panel is shown floating near your cursor Took the 'will survive here' text out of the requirements panel Set the maximum mutation rate to 35%, as higher mutations only cause a lot of small new subspecies that never gain enough traction to become full species The time jump view now shows mutation events, so you know evolution is happening even when…
- Patch v13.44 - 3 February 2026
Overhauled optimization mechanism that decides which 3D models to show Building procedural 3D models on the fly is expensive; on most modern hardware, showing an accurate model for each plant and animal in realtime is not feasbile. Therefore, as an optimization mechanic, until now only populous species got their own models, which was an acceptable approximation for some time. However, ever since I made a change to how speciation works a few years back, causing many more species, a lot of players noticed this optimization mechanism partly ruined the gameplay experience for them. The revised speciation patch two weeks ago, which significantly decreases the number of species, was already a first phase to fix this problem. This week, I take it a step further and introduce a revision to the mechanism itself. In this new approach, the game will still prebuild the most populous species; the ma…
- Patch v13.41 - 24 January 2026
Completely overhauled how species are detected So far, species classification was based on the features of an organism. Simply put, if a plant evolved a new type of leaf, or an animal evolved a new type of fin, the game decided this was a new species, without giving it further thought. For longer simulations, this resulted in hundreds of thousands of species (99% of which only had 1 organism before going extinct), eating up RAM and disk space. Now, instead, the game only considers a subpopulation of a species a new separate species if it's large enough. This solves many of the tech problems and seems to be more intuitive to players, but also brings new challenges. Most notably, large species might have one or more subspecies that are different from the main species in one way or another, but not large enough to justify branching it off; think of a single stemmed plant having a grass sub…
- Patch v13.40 - 10 January 2026
This is the first time the new movement update is available to everyone, regardless of whether you chose the beta. A quick overview of all new features: This is what has changed since the movement update patch last week. Fixes for juveniles and the red torso length handle in the animal editor When changing posture of adults, and juveniles have the same posture, also change it for the juvenile... fixes unexpected behavior and ALSO prevents crashes related to accessories on top (thanks, Shemariguess, al!) For juveniles, have the handle at the correct position also when the posture is different from the adult form Fixed handle initially not responding when looking at the juvenile form of an animal Made sure the handle is at the correct position when entering the editor Various fixes for volcanoes Fixed not being able to highlight a volcano directly after creating it Moving a volcano now al…
- Patch v13.39 (beta only) - 3 January 2026
Improved upright bipeds Added arm swing animation for animals with arms Upright bipeds no longer have their feet clip through the ground when placed Upright bipeds no longer slowly sink into the ground when walking Prevented walking animation problems for creatures with limbs that do not walk, like fins or arms Other animation improvements Revised walking animation parameters for the 'long but lightweight leg' and 'sturdy' limbs Remodeling the hopping leg to better work with the procedural walking system Improved special animation for 'water surface walker' (thanks Komodo, TealClaw, Jupiter hater!) Avoid some weird looking idle animations for animals with arthropod legs Created special dying, sleeping and egg laying animations for animals with arthropod legs Fixes for seasons Climate zones are now updated when a season changes mid simulation When looking at the statistics overlay while…
- Patch v13.33 (beta only) - 27 December 2025
Resurrected the scenarios Tested and rebalanced all scenarios to work with the new features of the movement update Redesigned the soil statistic button to have a planet icon Added new terrain overlay steepness stats and climate zones to all scenarios For all scenarios, added new limbs to 'anchored body parts' (which don't require mutations to reach) wherever it made sense Prevented plants spreading all of their seeds in the beginning of their life (which could happen with large seed surpluses that the disaster scenario requires) Resurrected the daily challenge Linked the new random terrain generator to the challenge generator Made the 'ocean floor walker' leg always unlocked, to give players easy access to the new arthropod limbs if they want to Disabled terrain editing tools Fixed the upper half of the 'let's go' button not registering clicks Fixes for small map sizes Drawing stats no…
- Patch v13.31 (beta only) - 20 December 2025
Reintroduced the 'randomize all' button The new version of the button generates small and large landmasses at random, using the new continent system. They can be moved and changed by the player. Most of the other random changes (like temperature, moisture, rings, etc) could be reused from the previous iteration of this button, but they're now also linked to the climate zone system so you can quickly see what has been generated for you. Polishing walking animations Fixed 'lightweight foot', 'fast hopping' and 'hopping' limbs not showing the hopping animation Made it possible for some (fast) legs to lift the feet higher, so it looks more like running Remodeled 'clawed, walking on toes' limb to better work with with the walking animation system Made it less likely that legs move in the incorrect order for any nr of legs (2, 4, 6, etc) Polished walking animation settings for 'knee', 'beside…
- Patch v13.30 (beta only) - 13 December 2025
More work on animation Added sleeping animations: animals squatting, moving head down and to the side Added egg laying animation (best visible in animals with a tail, because they move it up) Optimized specializing animations to player designed animals, and made it possible for an animation to only affect the first limbs (instead of all of them) Changed animation where tailless aquatic animal swim with their fins: they now only move the first set of fins More natural flying animation: made downwards wing movement faster and upwards wing movement slower Made undulating swimming animation symmetrical Working on limb body parts Added animation weights to 'ocean floor walker', 'filiform', 'hopping', 'spindly' and 'swings between branches' limbs (which reveal they need a separate set of animations) Went over all limb stats in detail for a first balancing iteration Fixes for seasons in the pl…
- Patch v13.27 (beta only) - 6 December 2025
Introducing save file format 13 Includes steepness of the terrain Remembers manual mode in the soil statistics view Updated the loading view explanation (which formats are supported) Working on flight with insect wings Animals with insect wings no longer stop moving when flying at normal time speeds Actually play the fluttery flight animation in the game Added aerial idle animations for rapid and fluttery flight styles Cleaned up buzzing noise, made it loopable, and start and stop it together with the flight animation Regular noise and flight noise are no longer mixed up Made the buzzing noise you hear (as example) in the editor much shorter No longer visualize movement noise with a growing sphere (like how calls and generic noise are visualized) Fixes for sessile animals Upright bodies no longer become thin at the base when there are sessile feet (thanks Cody Beaver!) Made 'sessile foo…
- Patch v13.26 - 30 November 2025
Working on body part loading Discovered that some limbs and accessories were saved incorrectly. This was hidden so far because the loading was ALSO incorrect, but will give problems in the future. From this patch onwards, some creatures saved with earlier versions of the game might load with other body parts than you remember. Found a few situations where the assets were loaded multiple times, fixed that to reduce memory usage and decrease loading times Finishing up parasitic fungus simulation Increased chances of parasites finding a host Parasites can now evolve into decomposers and back Parasites can now evolve to specialize for another host The population size updates now also support parasites, so you can see how successful your parasites are Parasites species are now also visible on the habitat map Made it possible to locate parasites in the world from the parasite species detail v…
- Patch v13.23 (beta only) - 22 November 2025
Simulation fixes I think I finally figured out how to prevent sessile feet on the side. This bug caused numerous problems, like plants multiplying, corrupt saves and missing models in the species list view. Added steepness of the terrain and how limbs differ in what steepness they support Also calculate the steepness underwater, as visible on the steepness map Got the steepness map also working mid simulation Added a maximum steepness statistic to limbs, editable in LimbStats.yaml Changed the limb stats view to show this new steepness statistic in the animal editor For the requirement panel when placing an animal, instead of just 'water', 'land' and 'steep', added various descriptions like 'mild slope' and 'cliff' In the simulation, made sure animals cannot walk on terrain too steep for them, and also don't lay eggs there Fixes for editing the terrain mid simulation Fixed problem where…
- Patch v13.22 (beta only) - 15 November 2025
Simulation fixes Prevented another way the sessile feet could evolve to be on the side. This bug causes numerous problems, like plants multiplying, corrupt saves and missing models in the species list view (thanks azul1462, TaterTot, MisterLiteralRandomGuy!) EDIT: hmm I just encountered this problem again, still not fully fixed Fixed sessile animal babies moving around (thanks ultraneongodpet, Jupiter Hater!) Working on new limb body parts Added a new gliding limb as intermediary step between insect limbs and insect wings Remodeled the pterodactyl wings to be more impressive and closer to reality Added top and back models for the exisitng gas bag body part Added second larger gas bag body part Fixed forcipule bodypart (was pointing the wrong way) Improved the hitboxes for various limbs, so it's easier to (re)move them Terrain editor fixes When hovering multiple continents, only the smal…
- Patch v13.21 (beta only) - 8 November 2025
Simulation fixes Fixed aquatic animal babies being stuck in the ground (thanks Hexadexx, Enzo Ramos Henrique, Ultraneongodpet, Kingdragon2026, Col. Caboose, bashclark1004, azul1462!) Fixed limbs mutating into sessile feet on the side, which the game cannot display (thanks AnniJPG!) Sped up time skips by removing excessive logs Working on new limbs Redesigned the limb stats view in the animal editor to match other stats view, including a place for a description Added bird leg with two toes, inspired by ostriches Added sprawling leg with long pointy nails, inspired by lizards Improved model for the fast, digitigrade leg (as used by the milk bug) Removed incorrect option to put new limbs on top and on the tail, where they looked like the starter fin Added all new body parts to the .yaml files containing the statistics, so they can be tweaked Removed that pressing D in the animal editor rem…
