The Cuban Tree Frog (Osteopilus septentrionalis) is a common, large amphibian often encountered in residential areas of the Southeastern United States, particularly Florida. This species uses a defense mechanism involving a toxic secretion, meaning the frog is poisonous, not venomous. They do not bite or sting to inject a toxin; instead, the compounds are released from the skin upon contact or when the frog is stressed. Understanding the nature of this toxicity and how to identify the frog is important for homeowners and pet owners in areas where it is established.
Understanding the Cuban Tree Frog’s Toxic Secretions
The distinction between a poisonous organism and a venomous one is based on the delivery method of the toxin. Cuban Tree Frogs are poisonous because their defensive compounds are passively secreted from the skin, requiring contact or ingestion to cause harm. They are not venomous, as they lack fangs or stingers to actively inject the substance. When handled or threatened, the frog releases a milky, sticky dermal toxin, known as a dermatoxin, from glands in its skin. This chemical defense is designed to deter predators. The composition of this secretion includes various compounds, such as biogenic amines and peptides, which are generally irritating.
How to Identify the Cuban Tree Frog
The Cuban Tree Frog’s size is one of its most recognizable characteristics, as it is among the largest tree frog species found in North America, with adults reaching up to 5.5 inches in length. Their skin is typically warty or bumpy, and their color is highly variable, ranging from shades of gray, white, or brown to an olive-green hue, with the ability to change color to match their surroundings. A distinguishing physical feature is the presence of very large, disc-shaped toe pads, which aid in their exceptional climbing ability.
The skin on top of the Cuban Tree Frog’s head is notably fused to the skull, a feature that distinguishes it from many native frog species. While native to Cuba, the Cayman Islands, and the Bahamas, this species is well-established throughout Florida and is expanding its range across the Gulf Coast. They are frequently found near human dwellings, often hiding in places like window sills, drain pipes, and around porch lights, where they hunt insects.
Immediate Effects of Exposure on Humans and Pets
The dermal secretions of the Cuban Tree Frog can cause immediate and unpleasant reactions upon exposure to humans. Direct contact with the secretion on the skin can result in irritation or a burning sensation. If the toxins reach the eyes, the reaction can be much more severe, causing intense pain and inflammation of the mucous membranes.
Domestic pets, especially dogs and cats, are most often exposed through licking or attempting to ingest the frog. The toxin produces a repulsive taste, which typically causes immediate, excessive drooling, pawing at the mouth, and head shaking in the pet. While rarely fatal, ingestion can lead to more concerning symptoms such as vomiting, difficulty breathing, and, in rare instances, seizures. The secretions are not considered lethal to pets, but they cause significant discomfort.
Immediate action is necessary if exposure occurs. For pets, the mouth and eyes must be rinsed immediately and thoroughly with running water to wash away the toxic mucus. Pet owners should wipe the gums and tongue with a wet cloth, sweeping the mouth from back to front to remove the substance. If a human has been exposed, the area should be washed with soap and water, and any eye contact requires immediate, gentle flushing with water. Contacting a veterinarian or poison control center is advised if severe symptoms develop or if the pet’s condition does not improve quickly.
Why These Frogs Are a Concern: Invasive Status
The prevalence of the Cuban Tree Frog and its frequent encounters with humans are largely due to its status as an invasive species in the United States. Accidentally introduced to Florida in the 1920s, the species has since spread rapidly across the state and into other parts of the Southeast. Their invasive success is supported by a high reproductive rate and a broad diet.
This large frog is a significant threat to native amphibian and lizard populations. They are voracious predators that actively consume smaller native frogs, often leading to a noticeable decline in local populations of species like the Green Tree Frog and Squirrel Tree Frog. By outcompeting and preying on native wildlife, the Cuban Tree Frog has established itself as the dominant amphibian in many urban and suburban environments. This ecological impact makes them a frequent subject of concern for homeowners.