Do oysters have legs?
A lot of people have different opinions about the question, with some saying their legs are so big they're hard to see, and others declaring that their legs are just the shell.
So, why does that matter?
"You could argue that your legs are very well camouflaged from predators, and we do see them more when the crabs are chasing fish, " said Dr David O'Neill, who has studied oysters in his role at the University of Wales.
But oysters have no such protection when it comes to protecting their appendages. The first thing that can happen to the body is if the oyster is crushed by something large, and if their legs get crushed it would be disastrous.
'Not very nice looking' But there are no known cases, he added, where an oyster was crushed and its body is so damaged that its limbs no longer look entirely human. The limbs tend to have a sort of "cobbled texture" as a result, or "a waxy appearance", he said.
"They look like they belong in a museum. " Dr O'Neill said that he does not have an explanation for why the legs are so large, but believes it to be the result of living in the water column for up to a quarter of its life- much longer than for most other creatures.
"If the oyster doesn't move in water then, yeah, the surface is flat. If they live in the deep the surface is more taut. If they move in water then the surface is sloped. So they are at a fixed point in the ocean, so how do they move on the surface?
" he said.
"We tend to think that the appendages are there for protection- for pulling up the shells that are underneath them, and for preventing the oyster from eating its own shells. " And if they are able to move on to new ground, they have little need for their legs.
"You have two types of sea creatures, living on land or seaweed, " said Dr O'Neill. "They are either moving on to new land or they are dead on the bottom. So if you don't have a set, the appendages would be very very, very small.
" Image caption It is not clear why the oyster legs are so long, which could make them difficult to see There are no known cases, however, in which people have died with limbs too long for human comfort.
So, the scientists believe, the length may be the result of a natural process. A lack of food "One of the interesting things we do on the ocean floor is that, generally, the food on the seafloor, and that would be oyster prey, is in the form of a kind of 'vacuum, ' where it is concentrated, and all the things that are important to the oyster such as calcium carbonate- which is responsible for the structure of this shell- are all there- but there is no one food source for them, " said Dr O'Neill.
"So they have to find other ways to find food, and we can think that they are looking for these structures. "And what we know about these shells is that when they come on the seafloor the shell itself is relatively small- and these are the parts that are found on the bottom.
"So if the shell has an organ on the end of it, like the shell of an octopus, or the shell of a clamshell, they are looking for a way to use some of those little appendages to move over and scrape food down on to their way of life that's hidden under that shell.
" The mystery of appendages "To really get to an answer I think one needs to focus a lot more, " added Ian Hutton, research professor at the School of Earth Sciences at University College London. Professor Hutton said there was a good example of how appendages could function to help with survival in the open sea.
"You have to remember that these appendages do come in handy- for example, if you're climbing out of the ocean, they help you to climb out, or to get a better vantage point for your camera, " he said.