Invertebrates
American Snout
Libytheana carinenta · also called American snout butterflies, snout butterfly
Resting motionless on a twig with its wings closed and its unusually elongated snout aligned against the stem, an American snout disappears into what looks like nothing more than a withered, curled-up leaf.
Overview
The American snout, Libytheana carinenta, is a small butterfly with an unusually elongated, beak-like facial feature, native to forest edge and open habitat containing hackberry trees across a broad range extending from the southern United States through Mexico and much of Central and South America. Its distinctive snout-like mouthparts, close dependence on hackberry trees, and capacity for staging some of the largest butterfly migrations ever documented in North America make it one of the more physically and behaviourally remarkable butterflies on the continent.
A face built for camouflage, not feeding
The American snout’s oddly elongated palps do more than give the species its name, helping a resting butterfly mimic a dead leaf’s stem closely enough to slip past predators that would otherwise spot it easily.
Status
Least Concern — widespread and common across suitable hackberry habitat throughout its extensive range, with populations capable of dramatic, temporary boom-and-bust fluctuations tied to rainfall.
American Snout: common questions
Why is it called the American snout?
This species has unusually elongated palps projecting forward from the head, resembling a small beak or snout, a distinctive facial feature far more prominent than in most other butterflies, and this unusual appearance is what gives the species its common name.
Why does the American snout sometimes appear in enormous numbers?
This species' caterpillar feeds almost exclusively on hackberry trees, and periods of favourable rainfall can trigger a flush of new hackberry growth that allows populations to boom dramatically, sometimes resulting in mass migrations involving enormous numbers of individuals, among the largest butterfly migrations ever documented in North America, particularly in Texas.
How does the American snout avoid predators when resting?
This species often rests with its wings closed and its elongated snout aligned with a nearby leaf stem, a posture that makes it resemble a dead or withered leaf rather than a butterfly, helping it avoid detection by predators despite its otherwise fairly plain, unremarkable wing colouration.
What does the American snout caterpillar eat?
This species' caterpillar feeds almost exclusively on hackberry trees, a strong dietary dependence that ties the butterfly's population size closely to the health and abundance of hackberry trees within its range, particularly following rainfall that promotes new leaf growth.