Natural History of the Salamander, Aneides hardiiJohnston, Richard F.
Science
Natural History of the Salamander, Aneides hardii
Johnston, Richard F.
Sacramento Mountain salamander
The primary study and collecting sites were four and six miles northeast
of Cloudcroft, Otero County, at 8600 to 8800 feet in elevation.
Vegetation was either almost pure stands of Englemann spruce (_Picea
englemanni_) or mixed stands of spruce, Douglas fir (_Pseudotsuga
taxifolia_) and white fir (_Abies_ sp.). At each locality small oaks
(_Quercus_) were present among the dominant conifers. Most of the
salamanders found were in downed Douglas fir logs; some were taken from
spruce and others from cracks in a variety of deadwood. In the less
deteriorated logs the salamanders lived under the loose bark or in small
cracks and chambers near the inner bark surface. In large fir logs in
advanced stages of decomposition, salamanders could be found to the
very centers. This kind of log was apparently highly favorable for
salamanders, for it was in such sites that we found notably large
numbers of the animals and most of the clutches of eggs that we
collected; this kind of log is not frequently found, for its wood is
saturated with water and completely punky and nearly ready for final
collapse.
In winter, salamanders that spent the summer at the surface presumably
move to subterranean cavities, or, at least, to sites away from winter
freezing. In December, 1957, and April, 1958, four feet of snow covered
our collecting sites, and the downed logs contained ice. A few logs were
wet at the surfaces where sunlight hit them, but just under such melt
they were icy. On May 3, 1958, snow was in isolated drifts and the
centers of the logs were still icy. On May 31, and June 22, 1958, there
was no ice anywhere, but no salamanders were evident. Late June is,
however, around the earliest time that _A. hardii_ emerges (Taylor,
1941).
Food and Foraging Behavior
We identified the contents of stomachs from 16 salamanders collected in
1956 and 1957; the items found in them are listed in Table 1. It is not
likely that this list is complete for prey species because _A. hardii_
eats a variety of food and probably takes prey almost indiscriminately
if it is of appropriate size. The kind of food most frequently eaten
was ants; they comprised almost 40 per cent of the total items.
Nevertheless, less than half the stomachs contained ants; this may mean
that salamanders do not make an effort to take ants over any other prey.
Such foraging behavior would result in random capture of ants, and it is
noteworthy that the frequency distribution of ants in stomachs suggests
a Poisson distribution, a mathematical description of one kind of random
distribution.
Table 1.--Numbers of Food Items Found in Stomachs of 16 Specimens
of Aneides hardii
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