Nuptial pad

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Nuptial pad (arrow) on thumb of Pelophylax esculentus

A nuptial pad (also known as thumb pad, or nuptial excrescence[1]) is a secondary sex characteristic present on some mature male frogs and salamanders.[2][3][4][5] Triggered by androgen hormones, this breeding gland (a type of mucus gland) appears as a spiked epithelial swelling on the forearm and prepollex that aids with grip, used primarily by males to grasp (or clasp) females during amplexus.[6] They can also be used in male-male combat in some species.[6]

Historical background[edit]

Austrian biologist Paul Kammerer experimented on midwife toads' nuptial pads.[7] He used the offsprings' apparent enlargening from generation-to-generation as evidence of Lamarckian evolution.[8]


Many amphibian species manifest nuptial pads for use in amplexus, an example being the rough-skinned newt, Taricha granulosa.[9]

See also[edit]


  1. ^ William E. Duellman; et al. (1994). Biology of Amphibians. JHU Press. p. 55. ISBN 978-0801847806. 
  2. ^ "Science & Nature - Wildfacts - Common frog, grass frog". BBC. 2008-07-25. Retrieved 2011-07-14. 
  3. ^ "Mertensiella caucasica". AmphibiaWeb. 1999-10-03. Retrieved 2011-07-14. 
  4. ^ "Ommatotriton ophryticus". AmphibiaWeb. 2005-10-26. Retrieved 2011-07-14. 
  5. ^ "Pleurodeles waltl". AmphibiaWeb. 2002-05-25. Retrieved 2011-07-14. 
  6. ^ a b F. Harvey Pough, Andrews RM, Cadle JE, Crump ML, Savitsky AH, Wells KD (2004). Herpetology (3rd ed.). Upper Saddle River, NJ: Pearson/Prentice Hall. pp. 67–68. ISBN 0-13-100849-8. 
  7. ^ Koestler, Arthur (1971). The Case of the Midwife Toad. Random House. 
  8. ^ [1] Archived September 17, 2008, at the Wayback Machine.
  9. ^ C. Michael Hogan (2008). "Rough-skinned Newt (Taricha granulosa)". Globaltwitcher, ed. Nicklas Stromberg.