The Creatures series consists of various games released by the companies known as Cyberlife, Creature Labs and Gameware Development.
Creatures is an artificial life (alife) computer program series, created in the mid-1990s by English computer scientist Steve Grand whilst working for the Cambridge computer games developer Millennium Interactive. The program is one of the few games (as of 2008) to employ machine learning.
Source: Wikipedia, Creatures (artificial life program), available under the CC-BY-SA License.
In Creatures, the player hatches small furry animals called "Norns" and has to take care of the Norns by teaching them the way of life. Norns have digital genoms and unique neural networks and can hand down their physical traits to later generations by breeding.