A spur is a bone covered in horn that grows out of an animal's body. While claws or nails grow from the toes, spurs grow on other parts of the foot. These parts are usually connected with joints. Spurs are mostly found on the hindfeet, but some birds have spurs at the edge of their wings.
In mammals[change | change source]
Not many mammals have spurs. The male platypus has spurs on the heels of its hind feet. The spurs are hollow and connected to a venom gland. This helps the platypus kick painfully. Echidnas have spurs as well, but they are not venomous. Fossils of some early mammals are found to have spurs also.
References[change | change source]
- Fisher, H.I. (1940). "The occurrence of vestigial claws on the wings of birds". American Midland Naturalist. 23 (1): 234–243. doi:10.2307/2485270. JSTOR 2485270.
- Rand, A.L. (1954). "On the Spurs on Birds' Wings" (PDF). The Willson Bulletin. 66 (2): 127–134. Retrieved 16 November 2012.
- "Australian Fauna". Australian Fauna. Archived from the original on 2016-03-04. Retrieved 2010-05-14.
- Griffiths, Mervyn (1978). The biology of the monotremes. New York: Academic Press. ISBN 0123038502.
- Hurum, J.H. (2006). "Were mammals originally venomous?" (PDF). Acta Palaeontologica Polonica. 51 (1): 1–11. Unknown parameter