Nature Notes From Crater Lake
Volume 24, 1993
Mustelids in Crater Lake?
By Michele Cardinaux
The term mustelid comes from the
zoological family name Mustelidae
and is used to refer to the group of animals in that family. Included in
this group are martens, fishers, weasels, ferrets, mink, wolverines,
badgers, skunks, and otters. Representatives of this group are found all
over the world and in almost every type of habitat.
Most members of the mustelid family are
relatively small, with long, low-slung bodies, short legs, short rounded
ears, and a thick silky coat. Primarily nocturnal (active at night), all
mustelids are solitary and remain alert throughout the year. Mustelids
are mainly carnivorous, eating small mammals, fish, birds, eggs,
amphibians, and some plant matter such as berries. Most of the species
in this family have paired anal scent glands, which in skunks are highly
developed for defense. In most other mustelid species, the secretions
are used more as social and sexual signals. Animals such as otters and
wolverines spend a great deal of time marking their "space" by rubbing
their scent glands on surfaces throughout their territory.
Mustelids exhibit a fair amount of play
behavior. Otters, for example, are noted for their ''playful" behavior
and spend time with other otters when engaged in "play." Of course, we
have to be careful about crediting animals with human attributes. Many
of these perceived "games" animals play are actually excellent training
exercises for survival because they strengthen muscles and sharpen
reflexes. It is interesting to note that the primate family (which
includes humans) is the only other group of mammals that consistently
exhibits such behavior.
Recently there have been several
sightings of mustelid-like animals in Crater Lake. At this point,
however, we have no confirmed reports of mustelids using the lake but
most of the human activity on Crater Lake is centered on a relatively
small portion of the caldera. The surface of Crater Lake covers 21
square miles, so there is plenty of room for an animal to remain
undetected. Since mustelids tend to be shy creatures and avoid human
contact, the difficulty in confirming sightings is probably further
compounded.
Crater Lake could be an attractive food
source for mustelids. Introduced fish and shellfish, as well as native
salamanders and invertebrates, are all possible mustelid foods. The lake
is also well within the ranges (which can extend from five to fifteen
square miles) of these animals.
What kindofmustelid may be using Crater
Lake? River otters are a dim possibility since they are known to fish
and swim. Otter sightings are rare in the park (none have been recorded
in recent years), so the most likely mustelid is the pine marten. These
animals are regularly sighted in the park and along the shores of Crater
Lake, but are not known to fish or swim. Although smaller in size than
otters or martens, the long-tailed weasel and short-tailed weasel swim
and are strong possibilities.
An example of a wildlife observation
form is shown below. The National Park Service needs well- documented
observations of the park's wildlife as a first step toward perpetuating
their existence. Studies conducted outside of the park can provide
better scientific understanding about mustelid species, but they cannot
determine if these animals are using Crater Lake. Only with detailed
observations (including length, color, shape or head, behavior, and
location) can gaps in the park's wildlife records be filled. Please ask
for forms at Crater Lake National Park's visitor information centers.

