Surinam toads, also known as Pipa pipa, are unique amphibians found in the murky waters of the Amazon basin. Unlike most frogs, they lack eyes that are large or well-developed and instead rely on other methods to detect prey. These toads carry their eggs on their backs and use their forelimbs in a striking way: they stretch them out in front of their mouths, with fingers spread wide, to sense movement in the water. When a small fish swims near, the toad swiftly opens its mouth, creating a powerful suction to pull the fish directly into its mouth—without a tongue—within a fraction of a second. A recent study led by biologists from UCLA has revealed that Surinam toads use their fingertips to detect prey in low-light conditions. Published in the Journal of Comparative Physiology A, the research uncovered a specialized sensory system in the frogs' front fingers. The study found that these fingers have unusual lobes—small, soft clusters at the tips—which act as highly sensitive touch organs. These lobes, first noted by 19th-century naturalists, were previously unexplained but are now understood to be crucial for detecting prey movement through water vibrations. The researchers used a scanning electron microscope to examine the surface of the frogs' fingers and discovered 128 tiny lobules per finger. Each lobe was covered with numerous dome-shaped bumps called papillae, similar to those found on the human tongue, which enhance touch sensitivity. When the scientists tested the sensitivity of the frogs' fingertips using calibrated filaments, they found that the neurons at the ends of the fingers were extremely responsive to touch, comparable in sensitivity to human fingertips. The study also identified dense clusters of touch-sensitive nerves in the lobules, despite these structures occupying only 8% of the total skin surface on the forelimbs. High-speed video footage showed that Surinam toads can detect prey as close as half a centimeter away, even in complete darkness. This ability suggests that the toads are using their fingertips to sense the movement of water caused by nearby prey. The findings highlight that the fingertip lobes function as tactile foveae—specialized sensory areas—similar to the highly sensitive appendages of the star-nosed mole. While such sensory magnification is typically associated with mammals, the study shows that frogs, which lack a brain cortex, achieve this through the optic tectum, a midbrain region. This discovery suggests that the evolutionary development of highly sensitive sensory areas is a widespread and ancient adaptation, found across different animal lineages.