The size of a small dog and sporting a thick coat of armor, this peculiar creature gets its name from the nine bands (or external “joints”) that circle its midsection and give the little tank some flexibility. The armadillo’s keen sense of smell can detect insects and grubs—its primary food source—up to 15 centimeters (6 inches) underground, and its sharp claws make digging for them a cinch.
An armadillo also digs underground burrows, into which it may carry a full bushel of grass to make its nest, where it will sleep through the hot day and emerge at night. Unlike armadillos that roll up into a tight ball when threatened, this species will race to its burrow, arch its back, and wedge in so that it cannot be pulled out. The tip of the Yucatán Peninsula  is a favored habitat for its scant rainfall; too much rain floods the burrow and can drown young armadillos.
A cousin of the armadillo, this extraordinary animal measures two meters (6.6 feet) from the tip of its tubular snout to the end of its bushy tail. Its coarse coat is colored shades of brown-gray; the hindquarters are darker in tone, while a contrasting wedge-shaped pattern of black and white decorates the throat and shoulders. Characterized by an elongated head, long tubular mouth, and extended tongue (but no teeth), it can weigh up to 39 kilograms (86 pounds). The anteater walks on the knuckles of its paws, allowing its claws to remain tucked under while it looks for food.
Giant anteaters are found in forests and swampy areas in Mexico and through Central and South America. It is mainly diurnal in areas where there are few people but nocturnal in densely populated places. Its razor-sharp claws allow it to rip open the leathery mud walls of termite and ant nests, the contents of which are a main food source. After opening the nest, the anteater rapidly flicks its viscous tongue in and out of its small mouth. Few ants escape.
South American tapirs are found from the southern part of Mexico to southern Brazil. A stout-bodied animal, it has short legs and a tail, small eyes, and rounded ears. The nose and upper lip extend into a short but very mobile proboscis. Tapirs usually live near streams or rivers, which they use for daily bathing and as an escape from predators, especially jaguars and humans.
Shy and placid, these nocturnal animals have a definite home range, wearing a path between the jungle and their feeding area. If attacked, the tapir lowers its head and blindly crashes off through the forest; they’ve been known to collide with trees and knock themselves out in their chaotic attempt to flee.
Next to deer, peccaries are the most widely hunted game on the Yucatán Peninsula. Two species of peccaries are found here: the collared javelina peccary and the white-lipped peccary. The feisty collared javelina stands 50 centimeters (20 inches) at the shoulder and can be one meter (3.3 feet) long, weighing as much as 30 kilograms (66 pounds). It is black and white, with a narrow, semicircular collar of white hair on the shoulders.
The name javelina (which means spear in Spanish) comes from the two tusks that protrude from its mouth. This more familiar peccary is found in the desert, woodlands, and rainforests, and it travels in groups of 5–15. The white-lipped peccary is reddish brown to black and has an area of white around its mouth. Larger than the javelina, it can grow to 105 centimeters (41 inches) long and is found deep in tropical rainforests living in herds of 100 or more. Peccaries often are compared to the wild pigs found in Europe, but in fact they belong to entirely different families.
Seven species of cats are found in North America, four in the tropics. One of them—the jaguar—is heavy chested with sturdy, muscled forelegs. It has small, rounded ears, and its tail is relatively short. Its color varies from tan and white to pure black. The male can weigh 65–115 kilograms (143–254 pounds), females 45–85 kilograms (99–187 pounds). The largest of the cats on the peninsula, the jaguar is about the same size as a leopard.
Other cats found here are the ocelot and puma. In tropical forests of the past, the large cats were the only predators capable of controlling the populations of hoofed game such as deer, peccaries, and tapirs. If hunting is poor and times are tough, the jaguar will go into rivers and scoop up fish with its large paws. The river is also one of the jaguar’s favorite spots for hunting tapirs, when the latter comes to drink.
The jungles of Mexico are home to three species of monkeys: spider, howler, and black howler. Intelligent and endearing, these creatures are prime targets for the pet trade. They have been so hunted, in fact, that today all three are in danger of extinction. Experts estimate that for every monkey sold, three die during transportation and distribution.
In an effort to protect these creatures, the Mexican government has prohibited their capture or trade. As you wander through the ruins of Cobá , keep your ears perked and your eyes peeled. You’re sure to see—or, at least, hear—a few tropical monkeys.
A tip: Spider and howler monkeys are most active at sunrise and sundown; if possible, consider waking early or staying late to increase your chances of spotting a few. Another places to see these monkeys is the Punta Laguna spider monkey reserve .