Five gecko lizards have died during a sex experiment aboard a Russian satellite, the Russian Federal Space Agency (Roscosmos) has said.
The Foton-M4 satellite returned to Earth on Monday, but all five geckos on board the satellite were found to have died at least a week prior, as their bodies were partially mummified.
Roscosmos has not reported the exact cause of death, but it is possible that the geckos died after the satellite heating malfunctioned.
The lizards were sent to space on 19 July to help scientists examine the effects of near-zero gravity on their sex lives and development.
The experiment found international fame after comedian John Oliver reported that Roscosmos had lost contact with the spacecraft of “sexually active space geckos” on his satirical television programme Last Week Tonight.
The mission also included studying the reproduction of drosophila fruit flies, and the development of plant seeds and mushrooms.