Ed Yong has a fascinating story about six Burmese pythons who were captured in the Florida Everglades (where they have become a voracious invasive species killing off the native wildlife), implanted with radio-transmitters to track their movements, and then let loose at various locations that were 21 to 36 kilometers away from their point of capture.
What the researchers discovered was that rather than wandering around their new habitat, all them set out on a fairly direct path to their capture point, with five of them ending up within five kilometers of home, with the other almost getting there but went off-course almost at the end for some reason. The study authors says that the “Translocated snakes moved straighter and faster than control snakes and displayed movement path structure indicative of oriented movement.” No one is quite sure where they get their navigational sense from, though there are theories.
Many animals, from pigeons to salmon to spiny lobsters, have incredible navigational skills, but this is the first time that any snake has demonstrated a similar acumen. They must have some sort of compass sense because they kept the right bearing, and they must have an internal map because they knew when they had reached the right destination.
For a compass, they could be picking up on the position of the sun or stars, the smell of home, or changes in the Earth’s magnetic field. As for the map, the snakes were always transported in sealed containers so they couldn’t memorise cues about their journeys as some animals do. They must be using some cues in their environment to work out their position but, again, we have no idea what those cues might be.
You can read the paper on which the article was based here.
The fact that the pythons returned to Florida and did not aim towards Burma means that they now look on Florida as ‘home’. Maybe we should stop calling them an invasive species.