Octopuses Have Six Arms and Two Legs…Survey Suggests
Freddie the common octopus at the National Sea Life Centre has helped marine experts make a remarkable discovery.
Octopuses regularly use all their tentacles bar the rearmost pair when gripping and manipulating objects, the survey at Birmingham’s and 19 other Sea Life centres has revealed.
Findings suggest that octopuses effectively have six arms and two legs…as their rearmost limbs are reserved almost exclusively for propulsion.
Data was gathered over a month, with visitors helping to record over 2,000 separate observations involving mainly common octopuses like Freddie…Octopus vulgaris.
Analysts believe their findings add considerable weight to the theory that tentacle choice is largely governed by sight, regardless of whether an octopus is grabbing food or playing with a Rubik’s cube.
More than half of the octopuses studied were found to display no bias at all for either right or left-sided limbs.
“The rest were split fairly evenly between those preferring the right side and those favouring the left,” said Sea Life displays supervisor Lynsey Thompson.
“We collected around 1,800 records relating to which specific tentacle was used first, over 370 records relating to pairs of tentacles and more than 50 records of three-tentacle sequences.
“The only real surprise was the frequency with which octopuses employ their third tentacles from the front on both sides.
“It was much more than we expected, given that earlier studies suggested the four rearmost limbs were reserved mainly for anchorage and moving across rocks.”
“An octopus’s eyes are angled towards the front of its body, so you would expect it to favour those arms more directly in its line of view,” said Lynsey, “and that’s just what we found.”
Tentacle use diminished front to rear on a steady curve, the front pair used 39 percent of the time, the next pair 31 percent, third pair 19 percent and the rearmost pair just 11 percent.
Lynsey and her colleagues had been secretly hoping that octopuses would prove to be the only other animals besides humans with a clear bias for one side over the other.
While renowned for their intelligence, however, it seems they’re no different to the majority in respect of their ‘handedness.’
No startling revelations then…but the Sea Life network has nevertheless made one very useful discovery.
“We’ve identified seven octopuses that genuinely do prefer one side over the other,” said Lynsey, “possibly because of some weakness in the other eye.
“Freddie had a very slight preference for the left side, but it wasn’t a significant bias.”
“If any octopus that does have a preference for one side or the other should fall sick we can now care for them more efficiently by delivering food and medication from that direction.
“Any measure that reduces stress with a sick animal, however slightly, can make a crucial difference.”
+ Permalink