Cadáver vs. carcaça
While both words translate to carcass or dead body in English, the distinction lies in the condition of the remains. Generally, cadáver refers to an intact dead body, often in a medical or formal context, whereas carcaça implies skeletal remains, a body stripped of flesh, or an animal prepared for butchery.
Cadáver
B1This word describes a dead body that is largely intact or has recently died. It is the standard term used in veterinary medicine, forensics, or biology. Use cadáver when focusing on the organism that has ceased to live.
O veterinário examinou o cadáver do cavalo para entender a causa da morte.
(The veterinarian examined the horse's dead body to understand the cause of death.)
Os bombeiros encontraram o cadáver do animal preso nos escombros.
(The firefighters found the animal's corpse trapped in the rubble.)
O cheiro do cadáver atraiu muitas moscas.
(The smell of the dead body attracted many flies.)
Carcaça
B2This word refers to the physical remains of an animal, emphasizing the bones, the skeleton, or the ribbed structure left after predators have eaten. It is also the specific term used in the meat industry for the cleaned body of an animal hanging in a butcher shop.
Os abutres limparam toda a carne da carcaça em poucas horas.
(The vultures cleaned all the meat off the carcass in a few hours.)
O açougueiro colocou a carcaça suína na câmara fria.
(The butcher put the pork carcass in the cold storage room.)
Encontramos apenas a carcaça branca e seca no meio do deserto.
(We found only the white, dry skeleton in the middle of the desert.)
Summary
In short, use cadáver for a whole dead body (clinical/formal) and carcaça for what is left over (bones/remains) or for meat production (the dressed body of livestock).