You’ll have to pay close attention to get even a quick glimpse of the glass frog when it’s at home in the Amazon rainforest. These tiny creatures spend most of their lives in the trees, only touching down during mating season. Fortunately, they’re comfortable in several locations of the mysterious Amazon, which gives you a solid “maybe” for seeing one on your adventure. And you may enhance your chance of spying these delightful, see-through amphibians if you use your feet rather than a boat to explore their habitat.

Meet the Glass Frog

Science has described more than 60 species of the glass frog, and experts suspect many more exist. They vary in size, with a few larger species reaching 3 inches in length. Most, however, are much smaller. The northern glass frog, or Fleischmann’s glass frog, for instance, measures from ¾ inch to 1 ½ inches as an adult, which is about the same size as your thumbnail. It’s one of the most frequently seen species of glass frog, and it prefers the subtropical and tropical forests of Central and South America as its habitat.

A See-Through Frog That’s Not Made of Glass

Glass frogs are so-named because their belly is nearly transparent, giving an X-ray view of their organs, bones and blood vessels. On top, however, they’re typically light green and may have darker and lighter variations in color that help them hide out in the trees of their choice.

They also have forward-facing eyes, a rather unique feature among frogs, whose eyes typically face outward or off to the sides. One lime green species, discovered in Costa Rica in 2015, made internet news as a “Kermit” look-alike because of its bulging white eyes with perfectly defined black pupils.

Three of four new species spotted in Peru, described in scientific journals in 2014, have green bones. The fourth was discovered at elevations higher than scientists thought they could live. This green charmer with dark speckles appeared in vast numbers one evening. Despite repeated attempts to better understand the species, however, researchers never saw a single frog after that first night.

One Peruvian species is mostly green other than its transparent tummy, but it produces tadpoles that are a striking pinkish-red that transforms to green as they age.

Enjoying the Amazonian Nightlife

Glass frogs are nocturnal, coming out at night to hunt for food, which scientists believes consists of flies, spiders and other small invertebrates. This makes them more difficult for daytime hikers to spot. But if you watch carefully, you may find them snoozing on a favored leaf or branch while the sun is shining. They prefer to settle high in the trees but make their way closer to the ground to mate and lay eggs.

Continuing the Species

Many of the glass frogs found in the Amazon rainforest affix their eggs to the undersides of leaves or to branches that overhang streams and other permanent sources of water. This allows tadpoles produced by the eggs to drop neatly into water, where they complete their transformation into adult frogs.

Males from the Fleischmann’s glass frog family stand watch over the eggs to protect them from predators and keep them moist until they become tadpoles. Males from other glass frog species prefer to eat their young. Most males and females simply ignore the eggs once they’re laid and let nature do the nurturing.

Where to Look for Glass Frogs in the Amazon Rainforest

The sheer size of the Amazon rainforest gives travelers hoping to spy a glass frog many places to search. Brazil captures about 60 percent within its borders, but Ecuador, Peru and many other South American countries claim a portion of the Amazon rainforest as their own. And while not part of the mighty Amazon, several countries in Central America have rainforests worthy of notice where glass frog populations also thrive.

No matter which country you visit, however, a walk rather than a boat ride will give you the best chance of meeting one of these elusive creatures in its natural environment. And if you miss finding a glass frog during your Amazonian adventure, you’ll still find plenty of wildlife to capture your attention and occupy your imagination. Besides, there’s always next time.

Disclosure Leaf Group is a USA TODAY content partner providing general travel information. Its content is produced independently of USA TODAY.