The order Chiroptera includes all bats and is unique among mammals as the only group capable of true, sustained flight. This ability requires a specialized body plan that has evolved into an astonishing spectrum of sizes. The diversity within this order is immense, spanning from creatures barely larger than a bumblebee to others with wingspans comparable to a full-grown eagle. This enormous range in physical dimensions reflects varied lifestyles and diets across more than 1,400 species worldwide.
The Absolute Maximum: Record Holders
The largest bat is the Giant Golden-crowned Flying Fox (Acerodon jubatus), endemic to the Philippines. This species holds the record for the longest wingspan of any bat in the world. The expansive membrane of this megabat can stretch over 5 feet 6 inches from tip to tip, roughly the height of a small adult human.
Despite their impressive wingspan, the body mass of these flying foxes remains relatively light for efficient flight, typically weighing between 2.5 and 3.3 pounds. As a member of the Megabat suborder (Pteropodidae), this creature is primarily frugivorous, relying on a diet of figs and other fruits. They do not use echolocation, instead utilizing their large eyes and keen sense of smell to navigate and locate food sources.
Defining Bat Dimensions
Researchers measure bat size using metrics more reliable than total wingspan, which can be difficult to measure consistently. The two most common standardized measurements are Forearm Length and Body Mass. Forearm length, the distance between the elbow and the wrist, is considered a robust indicator of overall wing size and flight capability.
Body mass, or weight, provides a direct measure of the animal’s bulk and is an important factor in metabolic calculations and flight mechanics. These measurements often help distinguish between the two traditional suborders: Megabats (Megachiroptera) and Microbats (Microchiroptera). Megabats are generally the larger group, relying on plant material like fruit and nectar. Microbats, which are mostly smaller and insectivorous, use laryngeal echolocation for navigation and hunting.
While the largest bats are Megabats, the size distinction is not absolute. The smallest Megabats can weigh only 13 grams, while some of the largest Microbats can reach almost 200 grams. Microbats use a sophisticated sonar system to capture tiny, fast-moving insect prey in mid-air. This sensory reliance on sound contrasts with Megabats, which possess well-developed eyesight and a strong sense of smell for finding stationary food.
The Opposite Extreme: Miniature Species
At the other end of the size spectrum is the world’s smallest bat, Kitti’s Hog-nosed Bat (Craseonycteris thonglongyai). This microbat is commonly called the Bumblebee Bat due to its diminutive size. Endemic to Thailand and Myanmar, it is one of the smallest mammals on Earth, competing with the Etruscan shrew for the title.
Its weight is astonishingly low, typically ranging from just 1.7 to 2.6 grams, which is less than a single U.S. penny. The overall wingspan of this tiny animal is only about 5 to 6 inches, comparable to that of a large moth. Like most microbats, it is an insectivore, relying on insect prey captured during short foraging flights around dawn and dusk.