Frogs: Trash exits via the bladder

New research about things that get under frogs’s skin, and what can happen to those things:

Removing the rubbish: frogs eliminate foreign objects from the body cavity through the bladder,” Christopher R. Tracy, Keith A. Christian, Lorrae J. McArthur and C. M. Gienger, Biology Letters. published online 2010. (Thanks to investigator Barry Pinshow for bringing this to our attention.) The authors, at Charles Darwin University, Darwin, NT, Australia, report:

“These observations led us to hypothesize that frogs may have a unique mechanism for eliminating foreign objects from the peritoneal cavity: they are moved into the bladder and then expelled during urination….

“This ability, as well as trans-intestinal expulsion, could lead researchers to draw misleading conclusions about mortality of telemetered individuals assumed to disappear owing to predation. Such incorrect conclusions could be dangerous by leading to inaccurate estimates of population dynamics for population viability models of endangered species.”

  • joe danda

    Interesting biology/physiology.

    According to M&M, beads and transmitters originally were implanted laterally on the left side of the body, while Figure 2-b shows that the bead is located on the right side of the body. Does this mean the implanted bead migrated from left to right and then to left again adjacent to the bladder? How does it find where the bladder is?

    The authors describe that beads implanted into frogs were first surrounded by a thin layer of tissue originating from, and attached to, the bladder. How did the authors know that the tissue was derived from the bladder? Is it possible that the thin (presumably fibrous) tissues initially were formed by macrophages in the peritoneal cavity recognizing/attacking the implanted bead as a foreign body, which then were fused with surface tissues (whatever they might be) on the bladder?

    Another question just for curiosity is: Where do frogs urinate, on the land or in the water?

    Additionally, this interesting biology/physiology reminds me of a Grimm’s Fairy Tale (Der Froschkönig oder der eiserne Heinrich), describing a prince (who turned into a FROG) and a princess (who lost a precious gold stone in a pond). The frog/prince found the jewel and returned it to the princess.
    After reading the current report, I wonder if the precious gold stone might have migrated through the bladder and excreted from the “cloaca” of the prince before it was returned to the princess???

    Finally, I look forward to seeing a of the bladder-rubbish theory by KEROMIN at the IG ceremony this year.