Object play in thick-toed geckos during a space experiment

Abstract

Play behavior was observed in thick-toed geckos (Chondrodactylus turneri GRAY 1864) during a 30-day orbital experiment on the unmanned spacecraft ''BION-M'' No. 1. The geckos wore ornamented colored collars which made it possible to track the behavior of individual animals on video recordings. The object of the play behavior was a collar that one of the geckos had managed to remove in the pre-launch period and which floated weightless in the animal holding unit under microgravity. Four of the five geckos participated in play episodes, which were defined as one-time interactions with the collar, as well in a fuller form of play that included approaching the unmoving collar or observing its approach, manipulations with the collar and further tracking the collar. Manipulations with the collar could take the form of complicated play, such as pressing the snout against the edge of the collar rim, multiple episodes of pushing the collar with the snout, inserting the head into the collar, holding the collar by pressing the head to the container floor and tilting the head with the collar on the snout. There were individual variations in play pattern. Explanations for the rarity of play behavior in reptiles under normal conditions and the geckos' playfulness in microgravity are discussed. Appropriate video is available at

Reptiles in Space Missions: Results and Perspectives

“…Behavioral analysis of video recordings was made after 12- and 30-day flights with thick-toed geckos [41,42] and 44.5-day flights with ornate day geckos [34]. The enzyme-linked immunosorbent assay (ELISA) study of excrements was spent only after 12- and 16-day flights [32] and cell cycle analysis—only after 16-day flight [30].…”

“…The geckos played with a collar that was removed by one of them in the prelaunch period and that floated under microgravity. Explanations for the rarity of play behavior in reptiles under normal conditions and the geckos’ playfulness in microgravity were discussed and the high adaptive capability of geckos for the space conditions was concluded [41].…”

“…Another problem is flotation experienced by vertebrates in spaceflights, which produce stress in animals and restricts the ability to move normally. Gecko bones also grow throughout life, but it is the unique natural model objects, that retain practically normal locomotion and behavior in weightlessness [6,32,41,42]. Reptiles possess a skeletal bone organization that is typical for vertebrates, consisting of the axial, limb skeleton, and neuro- and viscerocranium.…”

“…The ability of thick-toed geckos to remain attached to smooth surfaces during weightlessness was clearly shown [26,31,32], although for a long time gravity had been assumed to be required for this [39,40]. This peculiar ability allows the geckos to keep normal activities and behavior during weightlessness [41,42].…”

“…To date, geckos have been used in a number of orbital experiments, in which the high ability of geckos to adapt to spaceflight conditions has been shown. The researches after 16- and 12-day orbital experiments onboard the unmanned spacecraft (USC) series Foton-M2 and Foton-M3, respectively, as well as after a 30-day flight on USC Bion-M1 included histological staining of internal organs [29,33,43,44];immunohistochemistry [33,44];X-ray Absorption Microtomography (XAM) [31,32,45,46];scanning Electron Microscopy (SEM) [45];X-ray Fluorescence Analysis (XFA) [45,46]; andbehavioral studies (Foton-M3, Foton-M4, and Bion-M1 only) [6,32,34,41,42]. …”