Monster Zero x SciFi Japan - Archive Only

So I finally saw this film,or I guess since it was subtitled I should say I saw Frankenstein Vs. Subterrainian Monster Baragon,and I have one question. When Frankenstein sets up the pit with all the grass and trees covering it (the one a tank eventually gets stuck in),what the hell is the animal he's trying to trap? The world's biggest mouse? It makes noises like a guinea pig,but the JSDF yells "Look out!!!" and scatters when it runs past them. The video was a little grainy,so maybe someone with a better copy of the film can make it out a little better.

I always thought it was a wild boar. Though it seemed oversized.