Would army ants decompose dead elephants or monkeys?

Answer 1

Some kinds of army ants, especially some African Dorylus species might sometimes eat some carrion, but most of their prey is live. The American species of army ants (Eciton etc) are even more likely to eat small live prey rather than doing much to carrion.

Many other ant species certainly will feed very actively on available carrion as long as it lasts, and they can be useful for cleaning bones etc, but most carrion decomposition of large animals is done by other large animals, such as lions, dogs and hyaenas.

Overall however, most carrion decomposition, especially of small animals is done by carrion flies of many, many species, such as flesh flies (in the family Sarcophagidae) and the blowflies in the family Calliphoridae (the bluebottles, greenbottles and others).

Many beetles, such as in the family Dermestidae (hide beetles) and Necrophoridae (burying beetles) also break down a lot of older carrion, largely after the flies have eaten the juicier bits.