Squirrels cannot drop their tails like lizards. Lizards use a voluntary action called autotomy, where specific muscles contract to sever the tail at a predetermined fracture plane as a deliberate biological defense. The squirrel, a mammal, lacks this specialized anatomical feature and cannot actively detach its tail. However, the squirrel’s tail structure is adapted to fail in a specific, sacrificial way when grasped, resulting in a traumatic injury that serves a similar purpose in predator evasion.
How Squirrels Lose Their Tails
Squirrels lose their tails through a passive, traumatic event known as “degloving,” which describes the peeling away of the skin from the underlying tissue and bone. The skin and fur are only loosely anchored to the vertebrae and musculature beneath, functioning as a protective sheath. When a predator or strong force grabs the tail, the outer layer strips away easily, much like removing a glove.
This involuntary separation leaves the tail bone exposed. The degloving injury often results in the exposed portion losing its blood supply, leading to necrosis. The dead segment will eventually dry out and fall off, or the squirrel may chew off the damaged section to prevent infection.
Common Triggers for Tail Loss
The primary trigger for a degloving injury is an external force applied directly to the tail, often in a life-or-death scenario. The most frequent cause involves a close encounter with a predator, such as a hawk, cat, or dog, where the tail acts as a sacrificial decoy. Allowing the skin and fur to slip off lets the squirrel rapidly pull free from the predator’s grip, leaving behind fur and skin while the animal escapes.
Accidental entrapment is another common external cause, particularly in urban environments. A squirrel’s tail can become caught in narrow spaces, such as doors, fences, or car engine compartments. When the animal pulls away sharply, the force shears the skin from the bone. Aggressive interactions with other squirrels or improper handling by humans can also initiate the degloving process.
Survival and Adaptation After Tail Loss
The tail does not regrow after loss, as mammals lack the specialized regenerative capabilities seen in many reptiles. The loss is permanent and immediately affects several of the animal’s survival functions.
The tail acts as a dynamic counterweight, particularly when squirrels are executing complex maneuvers like leaping between branches or running along thin wires. Without a full tail, the squirrel must adopt an altered gait and climbing technique, often resulting in shorter jumps and more cautious movements to compensate for reduced balance.
The tail also plays a role in thermoregulation, as squirrels can wrap their bushy tails around their bodies for warmth in cold weather or hold them over their backs for shade in high heat. Furthermore, the tail is an important tool for social signaling, communicating alarm or interest to other individuals. While a tailless squirrel can survive, especially ground-dwelling species, the permanent handicap makes life more challenging for arboreal species.