Whether it's deciding what to buy for dinner or whether to take a new job, we make rational choices all the time. Scientists have long wondered whether this careful decision-making process is used by other members of the animal kingdom and how far they are from the human lineage. Now experts have discovered that fruit flies show signs of rational decision-making when choosing a mate. The researchers only tested mate choice in male flies, but the decision to mate in this species is definitely a two-way street. However, Dr Arbuthnott focused on male mate choice in the experiments detailed in the journal Nature Communications, to help dispel a misconception about mating in many animal species.