It’s not always easy to tell when an animal is in pain. This can even be distressing for pet-owners, for instance, but it’s the animal which is suffering, and unless it can communicate that it’s in pain, treatment may not be possible.

A new video from TED-Ed offers some perspective. It’s easier with animals which are more like humans, such as mammals, are easier to understand because it’s often obvious when they’re in pain. But there are things that are less obvious, such as their reaction to pain-relievers and how these help.

Remember that the more different the animal is from humans, the harder it is. The video asks: how do you tell when a shrimp is in pain, for instance? Or a snake?

Experiencing pain is divided into processes in humans. Our nerves and skin pick it up first, communicating the message to the spinal cord and alerting the motor neurons. Without this, even animals wouldn’t be able to survive.

The second part, however, is related to cognition and is the bigger chunk in the puzzle. It is more complex with things like fear, panic and stress getting involved. This makes one wonder, how does this work for invertebrate animals, and how much much pain do they consciously recognise?

And how do we avoid causing unnecessary pain in our world where practices such as eating live octopuses (who are considered to be one of the most intelligent invertebrate animals) still exist?