Although nearly always described as ‘retractile’ claws, the claws of the domestic cat are technically ‘protractile’ for the reasons stated and illustrated in the infographic below.
Here is an extended treatise of the above infographic.
The claws of domestic cats (Felis catus) are retractile, though the term “protractile” is technically more accurate. Here’s how their claw mechanism works:
Anatomy and Function
- Claw Structure: Cats have keratinized claws attached to the end of each toe, growing from the bone (distal phalanx). These claws are curved and extremely sharp.
- Retracting and Extending:
- In the resting position, the claws are retracted and sheathed by skin and fur. This is not an active process but rather the natural state due to the configuration of the tendons and muscles in the paw.
- To extend the claws, cats contract the digital flexor tendons, which pull the distal phalanx forward, unsheathing the claw. This is an active process, controlled by muscles in the leg and paw.
- Once the flexor tendons relax, elastic ligaments return the claws to their sheathed position, keeping them protected when not in use.
- Purpose:
- Protection: Retracting the claws prevents wear and tear on the sharp tips, ensuring they remain functional for hunting and climbing.
- Stealth: Sheathing the claws allows cats to move silently, critical for stalking prey.
- Versatility: By extending their claws selectively, cats use them for various purposes, such as climbing, defending, grooming, and capturing prey.
Why Retractile/Protractile?
The term “retractile” is used to describe the ability to withdraw the claws. However, because extending the claws is the active process while retraction occurs passively, “protractile” is more accurate scientifically. Despite this, “retractile claws” remains the common terminology.
This unique adaptation distinguishes domestic cats and other members of the Felidae family (except cheetahs, which have semi-retractable claws) from many other animals.
