Crustaceans such as crabs and lobsters are the only animals that we regularly cook alive.
They're usually prepared for eating by putting them straight into boiling water.
Experts say that way you can guarantee they're fresh and less likely to make you ill.
Now scientists from Queen's University Belfast say they've found the best evidence yet that crustaceans can feel pain.
They did experiments on shore crabs and saw that they respond to electric shocks and then go on to avoid them.
It's difficult to study whether animals feel pain because not all of them show it in the same way as we do.
What do you think?
What do you think about this story? Is it cruel to boil crabs and lobsters alive? Or do we need more evidence before we change the way we cook them?
This chat page is now closed. Thanks for your comments. You can read a selection of them below.
"I think it's horrible that we cook them alive, they feel pain just like us! If other animals are killed first before we cook them then why shouldn't they?!"
Vicky, Norfolk, England
"I think that it's very cruel to treat any living thing that way. How would you feel if you were boiled alive?"
Olivia, York, England
"It doesn't matter whether we think they have any feelings or not, it's wrong to cook animals alive."
Tom, Blackburn, England
"I think cooking crabs alive is extremely terrible and we should remind people that we should treat others how we would want to be treated."
Edie, London, England
"We don't think crabs should be cooked alive because it cruel and you wouldn't like it so leave them alone!"
Jasmine, Emily and Holly, Warrington, England
"I think they shouldn't be boiled alive because they are animals and they have feelings just like everyone else."
Ellie, Leicester, England
"No other animals are cooked alive, so it is NOT fair to cook them alive."
Charlotte, Gloucestershire, England
"I think that just because crabs and lobsters can't show us they are in pain doesn't mean they don't feel it. We should assume all living things feel pain and treat them with respect. KILL it before you COOK it!"
Charlie, Shropshire, England
"I think that it's really cruel that some people cook crabs and lobsters alive. I think they should either kill them first and then cook them or just not eat them at all!"
Daisy, Shrewsbury, England
"I think it is really cruel because we are putting them in so much pain."
Tia, Bath, England
"I think that chefs should not cook crabs and lobsters alive because it's cruel and disgusting."
Regan, Milton Keynes, England
"I think it's absolutely horrible and disgusting to cook animals alive, nobody would want to be cooked alive so why cook animals alive. Do not kill them in the most painful way."
Agnes, Wallington, England
"I think that it's horrible to boil crabs alive, they have feelings too. I think that the people who cook them should kill them first."
Jodi, Swansea, England
"I think that it's cruel, the fishermen should have the decency to kill the crabs painlessly so they do not feel any pain."
Joshua, Lancashire, England
"I think it's really mean that we cook them alive. Even though it stops us from becoming ill, it still seems wrong. They are creatures too and none of the other animals are cooked alive so why should they."
Zara, Surrey, England
"I think crustaceans should not be boiled alive because they feel pain, it's not fair for them to feel pain."
Sarah, Kent, England