Calakmul  is deep in the Calakmul Biosphere Reserve, a dense protected forest teeming with animal life. Look for howler and spider monkeys, toucans, parrots, and other assorted birds and rodents as you wander the site, as well as on the winding 60-kilometer (37-mile) road from the highway to the entrance. The reserve is home to five of Mexico’s six wildcat species, including jaguars and pumas, and every so often visitors are treated to a glimpse of one.
Everyone will tell you that in order to see wildlife, you need to visit Calakmul early in the morning. But think about it: even if you leave Xpujil at 5 a.m.—ouch—you don’t get into the core of the reserve until 6:30 a.m., well past sunrise. (And how many creatures will you spot from your car, anyway?) Worse, you’re dog-tired for the actual ruins, which are huge.
We recommend you wake up at a reasonable hour, have a good breakfast, visit Balamkú  on your way in (you’ll be too tired on your way out), and get to Calakmul  with enough time to be finishing up around 4 or 5 p.m. That’s the time birds and monkeys return from feeding to hang out in the trees near the ruins, and you’re liable to see just as many as in the morning.
The exception is the big cats, which, yes, are most active just before dawn. Then again, we spotted a puma (our one-and-only) trotting down the road at 5 p.m.!
The fact is, spotting animals is mostly a matter of luck. Even if you don’t see many (or any at all), the jungle is impressive, especially viewed from atop one of the pyramids.
From the entrance, a path leads about a kilometer (0.6 miles) through the forest before splitting into long, medium, and short routes. The long route loops past two smaller complexes, and begins in earnest in the Gran Acrópolis . The short route leads directly to the Gran Plaza , which has the largest and most impressive structures.