Caterpillar may need more time to dig itself out of the hole. Image source: Company website

When Caterpillar (NYSE: CAT) issued an unexpectedly dismal outlook for its first quarter a couple of weeks ago, the stock curiously continued to inch higher. Investors, perhaps, believed that the worst was over for the heavy-equipment manufacturer. But that may be far from the truth, as times have been tough for the entire industry.  The Manitowoc Company (NYSE: MTW) is aggressively restructuring to combat the sluggish demand for construction equipment, and mining giant Joy Global (NYSE: JOY) expects its 2016 sales to drop by 22% as miners continue to delay or scrap expansion projects.

Should we expect, then, that investors' optimism will be short-lived? While Caterpillar bulls have fairly good reasons to be excited -- as I highlighted in a recent article -- the bears could soon take charge, given some of the massive challenges ahead for the company. Check out the slideshow below for the bear argument on Caterpillar.