Gravel in the disgestive tract of axolotls. (fwd)

malacins malacins at
Thu Dec 3 14:07:31 EST 1998

When we kept our animals in fish tanks, with gravel filtration systems,
using the smaller size gravel normally used in tropical fish tanks, we
often saw them "eating gravel". We noticed no ill effects. However, being
alarmed at what seemed like "abnormal behavoir", we overlaid the small
gravel with larger size pebbles, which they could not possibly ingest.

Thus, we too observed "gravel eating", but didn't follow it up.

cheers, g. m. malacinski, I.U. Bloomington

George M. Malacinski, Ph.D.
Professor of Biology
Department of Biology
Indiana University
Bloomington, IN  47405
Fax (812) 855-6705

---------- Forwarded message ----------
Date: Wed, 2 Dec 1998 11:38:12 -0600 (CST)
From: umbjork1 at
To: nobody at
Newsgroups: bionet.organisms.urodeles
Subject: Gravel in the disgestive tract of axolotls.

We recently completed an x-ray series of five animals during limb 
regeneration. As a serendiptous side discovery we noted that the animals 
are regularly taking in gravel. We estimate these adults have about 10 
grams of rock of various sizes (3 mm to 1 cm) at any one time. These rocks 
are moving through the digestive system throughout the x-rays series. We 
began monitoring the animals excretions and discovered the gravel is passed 
regularly in the normal waste. 

We are wondering if this represents a pathogenic concern or do wild 
salamanders take in gravel normally? If they are taking gravel on purpose, 
are the animals using the gravel as ballast? Are they using the gravel the 
way a bird's gizzard works? Is the intake of gravel in our animals an 
effect of the artifical environment we keep them in? (We use and under 
gravel filtration system.) Our animals seem to be in perfect health, 
spawn naturally and frequently, and our larvae grow rapidly.

Any comments appreciated.

Natalie K Bjorklund
University of Manitoba's Colony

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