Talk:Grimace scale

Mammals only?
Does the grimace scale apply to mammals only? Or there some sense in which the scale can be applied usefully to fish, birds, reptiles and/or invertebrates? --Epipelagic (talk) 00:10, 14 January 2016 (UTC)
 * I wish it could, but I have not been able to find any research on this. Orbital Tightening could probably be used in birds and reptiles (I suspect it probably already is used informally when humans are assessing pain). Some birds have "whiskers", the position of which could be used in a scale and some also have combs the position/colour of which have already been used in welfare assessment previously.  Not so sure about fish grimacing when in pain, that is IF they experience pain ;-)  DrChrissy (talk) 16:28, 14 January 2016 (UTC)
 * Perhaps the absence of facial expressions in non-mammals contributes to scepticism about whether non-mammals experience pain. I suppose we are somewhat wired, sympathetically, to think of grimace as being evidence for pain, but really it shouldn't enter as a consideration for whether non-mammals feel pain. --Epipelagic (talk) 22:21, 14 January 2016 (UTC)
 * I could not agree more. We (primates) are highly social animals and it is advantageous for us to advertise that we are in pain (e.g. with a grimace) as this solicits attention from our group members (they may assist by licking a wound, sharing food, sharing warmth, etc).  For many other animals, they are a prey species and need to remain stoical when in pain so they do not advertise to predators that they are more vulnerable. DrChrissy (talk) 22:30, 14 January 2016 (UTC)

Why there is no grimace scale for non-human primates (e.g. bamboo lemurs)?
$addl3backtamar1n134 (talk) 15:51, 14 March 2021 (UTC) I learned that ferrets, mice and rats also (like monkeys and apes) have grimaces and was glad that they "can" move their upper lips. But I read carefully and noticed that they use nose rather than lips. So do non-human primates bulge/flatten the nose? Just strepsirrhines? And do mouse lemurs retract whiskers (they likely have whisker muscles) in pain? Trivia: dogs have wet nose but they have mobile upper lip and can snarl.