The Mexican White-lipped Frog (Leptodactylus fragilis) might be small, but it’s got a surprisingly bold personality. This little frog is known for its distinctive white lip, loud calls, and the unusual habit of laying eggs in foam nests. Though it’s more commonly found further south, this species just makes it into the southern tip of the United States, adding a tropical feel to places like Texas.
Size & Physical Appearance
Mexican White-lipped Frogs are small and slender. Adults usually measure between 1 to 2.5 inches long. Their bodies are somewhat flattened, with long legs that help them jump quickly through grass and underbrush.
They’re a light tan to gray-brown color with darker brown blotches or stripes on their backs and legs. Some individuals show a light line down their spine. Their most distinctive feature is the thick white stripe along the upper lip, which gives them their name.
Males and females look quite similar, but during the breeding season, males may show darker, more prominent throat patches and are more likely to be heard calling near water. Juveniles look like mini versions of adults but may have more pronounced color contrast.
Habitat and Range
This frog prefers warm, open environments and is usually found in grassy fields, savannas, agricultural areas, and wetlands — often near still or slow-moving water. They’re especially common in areas that are seasonally flooded.
In the United States, their range is limited to extreme southern Texas, particularly in the Rio Grande Valley. But outside the U.S., they’re widespread from Mexico down through Central America, and into northern parts of South America.
They favor lower elevations and rarely occur in mountainous regions.
Diet
Like many frogs, the Mexican White-lipped Frog is an insectivore. In the wild, its diet includes:
- Ants
- Beetles
- Spiders
- Small moths and other flying insects
They have a sit-and-wait hunting strategy — hiding in grass or leaf litter and quickly snapping up prey that wanders too close. They’ve also been observed eating smaller frogs and even their own tadpoles in rare cases, especially when food is scarce.
Lifespan
In the wild, these frogs typically live 3 to 5 years. Lifespan in captivity might be slightly longer, but they’re not commonly kept as pets or in zoos in the U.S.
Identification Tips
These frogs can be tricky to tell apart from other small brown frogs, but the following features can help:
- White stripe on the upper lip: This is the best field mark. It’s bold and usually easy to spot.
- Size and shape: They’re more slender and less warty than true toads, and smaller than most leopard frogs.
- Call: Males make a loud, high-pitched “weeeep” that carries well through grassy areas, especially after heavy rains.
They might resemble Coastal Plains Toads or small Southern Leopard Frogs at first glance, but once you get to know the look of that white lip and smooth body, you’ll start spotting them more easily.
Fun Fact
These frogs make foam nests for their eggs! During the breeding season, males and females whip up a frothy mass using their legs and lay eggs inside. The foam keeps the eggs moist and safe from predators until rain fills the pools and kicks off tadpole development. It’s one of nature’s clever solutions to tricky breeding environments.
Final Thoughts
While they’re not the most widely seen amphibians in the U.S., the Mexican White-lipped Frog adds a unique tropical flair to the southern Texas amphibian scene. If you’re exploring grassy or marshy land after summer rains in the Rio Grande Valley, keep an ear out and a sharp eye — you might just spot one of these sleek little frogs calling from the shadows.