Why bother mutating thugs when you stole the Rhino and the Warthog?

[neatoman]

Why did Shredder bother to mutate Bebop and Rocksteady when he went ahead and stole the animals? Even if we assume the rules are that a blood sample isn't enough and you need the whole animal around to make the mutation work, you could still cut out the middleman (middle test subject?) and just mutate the animals. One could argue that the animals wouldn't be skilled enough but the Turtles can't have been mutants for more than a few weeks (unless Shredder has had the Technodrome for years and never used it for much) and they seem more than skilled enough, and it's not like Bebop and Rocksteady can be considered skilled... Or even intelligent. And even if he really felt like mutating the humans was necessary, why not also mutate the animals? That way you have two sets of Rhino/Warthog mutants.

What happened to the animals anyway? They weren't returned to the Zoo, so where did they go? Is the implication that they somehow fused to the thugs, creating Bebop and Rocksteady? Were there actually two sets of Bebop and Rocksteady all along even though we only ever saw one at the time? Did Shredder turn the Warthog into hotdogs? Did the turn the Rhino into boner pills?

Spoiler:

Wouldn't it be funny if it turned out that Bebop and Rocksteady actually were the Zoo animals all along, and that Shredder only needed the thugs to strip naked so he'd have a set of clothes for the new mutants?