Spreadsheet "all Open Field": contains all data that were used to analyse Open Field behaviour across generations Spreadsheet "all Novel Environment": contains all data that were used to analyse Exploration behaviour across generations Spreadsheet "Novel Environment + Open Field": contains all animals for which we had Novel Environment and Open Field data Spreadsheet "Fecundity + Gen time": contains breeding data for all individuals that reproduced at least once generation F0 = founder, F1 = first generation, F2 = second generation, F3 = third generation trial 1 = first test, 2 = repeat after 4 weeks treatment HQ = high quality food, SQ = standard qualit food enclosure one of the four semi-natural enclosures ID individual identity sex f = female, m = male OF_distance distance run in 5 minutes Open Field [cm] centre_time percentage of time spent in the center of the open field NE_latency latency to enter the novel environment [s] NE_trips number of exploration trips within 5 minutes after entering the novel environment NE_exploration time [s] a mouse spent explorating in the novel environment M2:M8 Succesive months for which breeding data was obtained Sum_offspring Total number of offsprings Fecundity_rate Fecundity rate GenTime Generation time The RNA-seq data reported in this article have been deposited  in  the  European  Nucleotide  Archive  (ENA accession  no.PRJEB39594)