Aesthetically Evolved Virtual Pets

“Aesthetic, emotional, and empathetic selection are applied to a derivative of Karl Sims’ Evolved Virtual Creatures. The resulting Creatures can be beautiful or strange, and provoke strong reactions in human observers. It may be possible to evolve virtual pets to which humans can form strong emotional bonds.” From 1990 to 2001, Thomas Ray conducted research on digital evolution, which means exploring what happens when evolution by natural selection is embedded in the medium of digital computation. This work began with the creation of ‘Tierra’, a system in which self-replicating machine code programs evolved by natural selection. In 2000, he implemented a new system called ‘Virtual Life’. In 2014, his ‘Aesthetically Evolved Virtual Pets’ video was runner-up in the Virtual Creatures competition at GECCO.


This work has been previously described in detail (Ray 2001), so here I will only describe what is contained in the video. All of these creatures are contained in the zoo of the VirtualLife software which is available for download at this location:

The bodies are composed of segments which are either boxes or ellipsoids. The creatures are grouped below based in part on which of these two forms the segments take. Also, the colors manifest by each segment can either be determined by the angles on the joints between segments, or on output from special color producing neurons. In the latter case, color reflects the internal state of the creature. The creatures listed below are also grouped in part on whether color is controlled by joint angles or neurons. Some creatures are visibly sensitive to touch, and they are also grouped by this quality.

Ellipsoid – Neuron

0:00 AnemonaeNeuron.gen

0:08 CoilFlower01.gen

0:17 FlowerWave33.gen – no color change, but great movement

0:30 CoilFlower02.gen

0:43 FlowerWave36.gen

0:55 FlowerWave73.gen – good flow of inner glow and movement

1:11 CoilFlower06.gen – smooth color changes, accelerates with movement

1:23 FlowerWave47.gen – double recursion, color flows down both chains

1:34 FlowerWave56.gen – good series of color flows, sometimes blows up

Box – Neuron

Not Touch Sensitive:

1:47 ColorFlowB54.gen

1:57 ColorBiFlow14.gen – strong forward flow with periodic pulsing, weak backflow

2:07 ColorSense01.gen – complex color changes

2:17 ColorSense02.gen – evolved one step from 01, no flow, but rich color dynamics

Touch Sensitive:

2:27 ColorFlowB28.gen – touch sensitive, color flow, x increases flow, z decreases flow

2.37 ColorBiFlow09.gen – touch sensitive, flat body, slow swimmer

2:47 ColorSense04.gen – when pulled in +- x, rapid rainbow flow

Box – Joint

Exploding, or Not:

2:56 Ladder13.gen – fast explode

2:57 LittleArmShakey.gen

3:12 MagnetsNew.gen

3:22 Magnets02.gen

3:37 Ladder13.gen

A creature with complex behavior:

3:51 Twister02.gen



Ray, T. S. 2001. Aesthetically Evolved Virtual Pets. Leonardo 34(4): 313-316.

Available at:


Aesthetically Evolved Virtual Pets video was runner-up in the 2014 Virtual Creatures competition at GECCO 2014


Thomas S. Ray website

Get the Full Experience
Read the rest of this article, and view all articles in full from just £10 for 3 months.

Subscribe Today

, , , ,

No comments yet.

You must be a subscriber and logged in to leave a comment. Users of a Site License are unable to comment.

Log in Now | Subscribe Today