Odd Historical Account, Late Roman Empire

[Mosaic]

I wonder if any history buffs have views or interpretations of the following. Ammianus Marcellinus described an incident around the year 379, when Gothic mercenaries who had been granted 'permission to stay' in the Roman Empire were enslaved and exchanged for dogs.
I'm struggling to understand the significance of this.
Why 'exchanged for dogs' - was this some symbolic humiliation above being enslaved? Was there a sudden need for dogs?
The phrase is repeated widely across all kinds of sources, but not explained.

[sandyRoe]

If prisoners were paraded during a Roman Triumph they were later taken and garrotted. Anyone have a source for this?

[DaisyNonna]

Do you want me to make another phone call Sandy? My source won't be available until tomorrow.

[sandyRoe]

I read that in a book, Imperium, and it seems likely, knowing the Romans

[Jackdaw33]

I have no real knowledge but sounds likely, as King Caractacus was spared after the triumph following his capture, by Claudius.

[Peter Pedant]

well Josephus describes the triumph of Vespasian after the fall of Jerusalem
and only the leader gets garotted:

http://www.eyewitnesstohistory.com/rometriumph.htm

I thought the others went to the colosseum or were sold

[Peter Pedant]

again - the chieftains were put to death - a habit so barabarous we can hardly credit it ...

http://penelope.uchicago.edu/Thayer/E/Roman/Texts/secondary/SMIGRA*/Triumphus.html

a truly incredible number of references

[Peter Pedant]

There is also a ref to Livy 26 13
Hannibal leaves the Capuans to their devises
and altho the ROmans cant claim a triump as Capua counts as a civil war
they certainly think it can
and the speaker foretells his own death

The English translation is here

http://www.perseus.tufts.edu/hopper/text?doc=Liv.+26+13&fromdoc=Perseus%3Atext%3A1999.02.0158

[Hypognosis]

@Mosaic

Consider which dog breeds might have had utility in those days and which breeds would have been anachronistic?

eg retrievers have no obvious purpose until guns are invented (unless archers were spectacularly talented) but sheepdogs and rabbiting types would have had inherent value.

Humiliation could be a part of it but captives run away, given half an opportunity whilst dogs loyally carry out their duties. Even the slaves would acknowledge how that would make an owner value the dogs more highly.

[DaisyNonna]

Apparently it was a favourite pastime of Julius Caesar. He paraded and then had all the prisoners garrotted, not just the leaders.