Glossary
Digit
The distal parts of a limb, such as fingers or toes.
These are named and identified by Roman numerals.
In a pentadactyl (five-fingered or five-toed) arrangement, the most medial digit, if present, is I (e.g. the human thumb) and the most lateral is V (e.g. the human little finger).
These are named and identified by Roman numerals.
In a pentadactyl (five-fingered or five-toed) arrangement, the most medial digit, if present, is I (e.g. the human thumb) and the most lateral is V (e.g. the human little finger).
Keratin
A protein that is deposited to form hard, tough and water-resistant epidermal (skin) tissues.
Keratin forms the outer layer of epidermis (skin), hair, nails, claws, hoofs, horns and feathers.
Keratin forms the outer layer of epidermis (skin), hair, nails, claws, hoofs, horns and feathers.
Protractile Claw
Claw that can be protracted (extended) from its protective sheath.
Cats’ claws are protractile, but often (misleadingly) described as retractile. At rest, the claw is retracted; muscular action (contraction) protracts the claw out of, rather than retracts it in.
Cats’ claws are protractile, but often (misleadingly) described as retractile. At rest, the claw is retracted; muscular action (contraction) protracts the claw out of, rather than retracts it in.
Nail
The tough, flat structure on the dorsal surface of a digit.
Made from a hard protein, keratin.
Nail is frequently used to refer to the claw of dogs. They are usually relatively blunt and non-protractile, and therefore usually register in a track.
Made from a hard protein, keratin.
Nail is frequently used to refer to the claw of dogs. They are usually relatively blunt and non-protractile, and therefore usually register in a track.
Register
To imprint a track on the substrate (ground).
Track
Impression or indentation made on the substrate (ground) by a foot.
Talon
The claw of a bird, usually bird of prey.
Hoof
The tough sheath that covers the tip of a digit of an ungulate.
Made from a hard, horny protein keratin.
Made from a hard, horny protein keratin.
Unguala
A nail, claw or hoof.