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Yosemite Snow Worm and Lincoln penny, Tioga Road at Crane Flat, March 1980

Research Proposal

The Natural History of Snow Worms (Mesenchytraeus sp.) in Yosemite National Park

A. Introduction

Starting in Winter/Spring 1978/79 I noticed snow worms (probably Mesenchytraeus gelidus) in Yosemite's snow every winter through 1985/86 that are similar to the ice worms (Mesenchytraeus solifugus) common on glaciers in Glacier Bay National Park and Preserve, Alaska.
This is an animal unreported in the natural history for Yosemite and California. They are interesting because of their close association with snow, a major resource in Yosemite National Park. They are dark colored and about 1 inch long. Looking closely at them we see they are a relative of the common earthworm due to their segmented body - they are actually in the same Order, Annelida. They were probably long overlooked due to their similarity to various conifer needles in the snow! They look like a fir needle.
The worms themselves, while seemingly insignificant, play a role in the ecology of snow. Their study can also be used as a teaching tool for techniques in field biology. The literature has several references to snow and ice worms. See some of them below.

Snow worms are segmented worms called Annelids, just like earthworms!

B. Objectives

To document and study the natural history of snow worms in Yosemite National Park.
To begin to understand their significance in the ecology of the park and the surrounding Sierra Nevada.
To develop teaching techniques in field biology for students and Yosemite Institute using snow worms as an example.

C. Management Implications

Snow worms are an indicator of the quantity and perhaps quality of snow. Their natural history should be understood by park interpreters. The study of snow worms will serve as part of an introduction to field biology for Yosemite Institute students and staff while further enhancing the role of research in Yosemite National Park.

D. Methods

Yosemite Institute instructors and students filled out fifty nine data cards from February 14, 1982 to February 24, 1986 with the format below. A four meter looped cord tied in knots one meter apart was thrown out into the snow in a random direction, often by a blindfolded student. The cord was then straightened out where it landed to form a square meter. As noted on the cards, many of the observations were made in selected, not random locations due to the limited number of worms observed in an area. The number of snow worms on the surface were counted and other data was documented:

Name, address and phone of observer(s):
Specific location:
Air temperature:
Surface temperature:
% Cloud cover:
Snow texture:
Snow depth:
Vegetation and cover:
Date and type of last storm: 
Snow worms per square meter:
Sample 1.
Sample 2.
Sample 3.
Sample 4.

E. Work Allocations

Yosemite Institute instructors and staff were and will be involved in the study. Collection of snow worms for identification will be by Mike Lee, Yosemite Campus Director, Yosemite National Institutes. Species determination will be by Dr. Kathryn Coates or another expert. Data will be summarized and made available for publication by Mike Rivers, former YI instructor, and Oregon Parks and Recreation Department Park Ranger.

F. Budget

The data for this project was gathered by staff and students on a volunteer basis. Equipment was minimal (index cards and knotted cords, thermometers) and paid for by instructors supplies funds. Financial costs for species determination will be donated by Mike Rivers and in-kind by Yosemite Institute. Data summaries and publication will be volunteered by Mike Rivers.

G. Duration of Study

Open. Three substantial seasons of data have been collected (1982, 1983, and 1984) and spot observations made in 1985 and 1986.

H. Report Period

It is assumed publication of the project would spark renewed interest and study of the snow worms. A paper would be offered for publication suggestions in a recognized Annelid journal, as well as popular articles offered to publications such as, "Yosemite - A Journal for members of the Yosemite Association," etc..

H. Literature Cited

Several of the references mentioning snow worms include:

I. Summary

With many thanks to Jan van Wagtondonk, Yosemite National Park Research Scientist, for his patience, I resubmit this research proposal as the application for a collection permit for the snow worms we researched so many years ago in Yosemite. Thanks to email and internet communication we have finally found Annelid specialists who can bring us the "first order of biology," a scientific name, to our unique creature in the snow!

Principal Investigators:

Mike Rivers
PO Box 275
Waldport  OR  97394


Yosemite Institute
PO Box 487
Yosemite National Park  CA  95389

Submitted By

Mike Rivers

Snow worm related links:

page updated 1/2/02