Research into how animals react in microgravity has been carried out for decades. Whether it’s investigating how geckos have sex in their privacy of their very own spaceship, or just how much trouble these researchers are going to be in once their floating cats find their footing, animals can reveal a lot about how microgravity can affect both the body and the mind.
According to Jason G. Goldman at io9, most animals, including various mammals, frogs and turtles, react to the weightlessness of microgravity as if they were falling upside-down. This confusion often leads to repeated summersaults - they just keep rolling over and over, not sure why the behaviour that would normally put them on their feet is all of a sudden not working the way it's supposed to.
But some species of reptiles and amphibians display entirely unique behaviours in microgravity. Some snakes get confused and attack their own bodies in microgravity. Worm-like creatures called caecilians become immobile and lose muscle tension. Some species of tree frogs just keep trying to dive down into nothing, over and over.
"That tree frogs think that they're diving makes a great deal of sense,” says Goldman at io9. "Caecilians may become limp simply because these animals, which live out their lives in the ground like earthworms, never have the possibility of falling, and thus never develop strong righting responses. But why would snakes attack their own bodies?”
To investigate this, in 2005 a group of scientists led by frog morphology expert Richard J. Wassersug from the University of British Columbia in Canada loaded a handful of western rat snakes (Elaphe obsolete) into a 'Vomit Comet', which is the rather playful nickname for a reduced gravity aircraft. "These are planes that fly in parabolas [sharp dips or curves]: as the plane moves over the top of the curve, everything inside is temporarily weightless. At the bottom of the curve, it the pull of gravity actually feels a bit stronger,” says Goldman at io9.
As the video footage reveals, the researchers found that through three parabolas, the snakes routinely knotted their tails and kept the rest of their bodies completely still. But why would they do this?
It could have to do with the loss of something known as proprioception. Proprioception is the sense someone has of the relative position of neighbouring parts of their body, and the understanding of how much strength is being used in order to move them. In other words, it’s a sense of self, and it could be that snakes lose this in microgravity.
That would explain why some snakes attack themselves in microgravity, and while Wassersug’s team didn’t see any of their snakes do that, they think that the knotting of the tails is the snakes trying to emulate what they’d do when they are stressed under normal circumstances - bunch up in a tight group with other snakes and lay still.
"In the absence of gravity, it appears as if snakes have a difficulty distinguishing self from non-self. The snake managed to relax, but only because it didn't realise that it was working to relax its own self!” says Goldman at io9. "At least, that's the hypothesis."
The researchers published their findings in the journal Zoology.