Just how crazy were film-makers willing to get to convey the awfulness of dinosaur combat, back in the day? Check out this horrendous sequence from 1960's Irwin Allen spectacular The Lost World, in which lizards covered with makeup battle.
When I watched this film on TV a while back, I was on the fence about whether those were real-life lizards fighting — their motions were so jerky, their skins so fake-looking, I just thought they were really well-done Harryhausen-style stop-motion creations. But no — as various commenters have pointed out, those are real life lizards, being harmed in the making of this film. As English professor Michael Delahoyde puts it on his Dino-Films page:
The dinosaurs are photographically enlarged lizards, and are enjoyable to see eating and slurping the air, but distressing to see encumbered with all the glued-on crap to make them into things that look like dinosaurs only insofar as they don't look like lizards anymore. Pitting the two lizards against each other for the fight scene is inexcusable. More humans need to be killed instead.
It is really depressing to think of the film-makers making the lizards fight, just for a dumb spectacle. We definitely do not condone cruelty to lizards or other critters in the making of terrible monster movies.
In any case, to make it up to you, here's a giant green spider that hopefully was allowed to scuttle away unharmed after this take: