Methods of Collecting and Preserving Vertebrate Animals

Rudolph Anderson

• Publisher: Oakley Press
• Year: 2020
• ISBN:
  9781528762649
• Topic: Biological Sciences
• Subtopic: Natural History
• Index: Biological Sciences

This early work on taxidermy is a fascinating read for the amateur or professional taxidermist and also contains much information that is still useful today. Forty-eight text and full page drawings and diagrams illustrate this compelling work. Contents Include: Preface; General Principles of Zoological Collecting; Collecting Mammals; Skinning Mammals: Small Mammals, Large Mammals, Mammals Requiring Special Treatment, Pelting Skins; Collecting and Skinning Birds; Collecting Reptiles, Amphibians, and Fishes; Collecting Skeletons; Permits for Scientific Purposes; References. Many of the earliest books, particularly those dating back to the 1900s and before, are now extremely scarce and increasingly expensive. We are republishing these classic works in affordable, high quality, modern editions, using the original text and artwork.

CHAPTER I

GENERAL PRINCIPLES OF ZOOLOGICAL COLLECTING

INTRODUCTION

The detailed and systematic study of animal life, which has advanced rapidly during recent years, necessitates extensive collections of specimens. The lower forms of life are most numerous, both in species and in individuals. Insect life is abundant in most parts of the world and the science of entomology now lists its species by hundreds of thousands. Improved vessels and new methods of deep-sea dredging have brought to light multitudes of new forms of marine life. Among the vertebrates, or back-boned animals, birds have always been evident to the most casual observer and the ornithology of civilized regions was scientifically studied at a comparatively early date. Collectors are continually bringing out new facts in regard to geographic distribution in all lands, and many new subspecies or geographic races are still being described from North America.

In field collecting, the first important thing is to catch the animal, and to do this it is helpful to know as much as possible about what animals may be expected to occur in a given area. Under References (page 145) are given titles and notes on a number of manuals and faunal lists which may be useful to a collector. Most of them will not be in small libraries, but a local naturalist will usually have some of them, and most good manuals and scientific papers give citations of other publications in the same field. Where possible, a collector should read every available publication on the area before he goes into a new field.

Mammalogy, or the study of mammals, though going far ahead in some lines, lagged for a long time behind other branches of systematic zoology. The anatomy, physiology, and pathology of the human race have been studied from remote antiquity and the results and technical names have been applied to the framework of the lower orders, but the lesser species were generally neglected. The principal reason for this backwardness is that, except for the larger mammals which are used for human food, or for their hides and fur, and others that are obvious pests, the majority of species of wild mammals are secretive in their habits and are seldom observed or taken unless vigorous and intelligent methods of trapping are used.

Miller (1929, 405)¹ attributes the recent development of mammalogy to two factors, an awakened interest in the nature and history of the life that now exists in the world, and the finding of a technique by means of which the study can be successfully carried on. The interest was aroused by the studies of Charles Darwin and the stimulating controversies that have never ceased to grow from his writings, and the technique was worked out by Dr. C. Hart Merriam, chief of the Biological Survey, United States Department of Agriculture, from 1885 to 1910.

The invertebrates (animals without a vertebral column) are more numerous and generally more easy to preserve than the vertebrates, but cannot be treated at length in this bulletin. However, as thorough field studies of vertebrates involve the collection and preservation of specimens of invertebrates, the student is advised to study a good textbook on ecological laboratory methods (Wight, University of Michigan, 1938, and others).

“Directions for Collecting and Preserving Insects” (McDunnough, 1928) may be obtained by application to the Dominion Entomologist, Science Service, Department of Agriculture, Ottawa. Small molluscs may be preserved in ethyl (grain) alcohol, but acids in some kinds of denatured alcohol (methyl hydrate) are apt to dissolve the calcium in the shells if they are immersed for any length of time. Large shells are usually cleaned of animal tissue and dried. Marine invertebrates of other orders, as well as land worms, slugs, etc., are generally preserved by immersion in alcohol or formalin, unless intended for histological or special biological investigations, when other methods may be used to prevent shrinkage of delicate tissues. The strength of the preservatives must be carefully regulated for the different classes of specimens (See section on “Preservatives, page 128).

The progress in the study of mammals may be judged by the fact that only about 150 species were known in North America a little over 100 years ago (Harlan, 1825), whereas the latest complete check-list (Miller, 1924) gives 2,554 forms inhabiting North America. Richardson (1829) listed 82 mammal species from British North America, and Tyrrell (1888) 137 species and varieties from Canada, whereas the latest Catalogue of Canadian Recent Mammals (Anderson, 1947) lists 594 species and subspecies of mammals known to occur north of the southern boundary of Canada, in addition to 2 introduced species and 49 of hypothetical occurrence.

The fact that a very large number of forms have been described and listed does not mean that our knowledge of them is complete in any case. Often a form has been described and named that appears to differ from all others, but only very few specimens may have been observed, and we are almost entirely in the dark concerning the extent of its range, its life history, economic value, or significance in the fauna of the country. All the larger mammals of Canada on account of their value as food or as fur producers, or because of their predatory habits, are without doubt known in a general way, and there is small probability of any new species being discovered. There are, however, local differences in some forms, due to geographical environment, that are worth studying, and few of our museums have really adequate numbers of specimens from the various regions. The differences in many cases are not readily apparent until specimens from different regions are brought together. With the advance of civilization and settlement most of the larger forms of animal life are rapidly disappearing all over the world, and many forms have become totally or nearly extinct within the memory of people now living. The necessity of obtaining adequate representatives of these rapidly disappearing animals for purposes of record and scientific study in the future is well recognized, but the haunts of the larger and rarer mammals are generally remote and comparatively inaccessible. The collecting of specimens becomes, therefore, both laborious and difficult. Few public museums have the resources for continuous and thorough work along these lines. Even the notable collections of such famous institutions as the British Museum and the Smithsonian Institution are largely due to the generous aid and contributions of private individuals outside of the technical staffs.

A considerable number of expeditions are made each year by sportsmen and big-game hunters into remote parts of the country, at considerable expense for equipment, transportation, and guides. Though many of the finer trophies are preserved and brought home, records are often lost and the trophies lose interest after the passing of the individual hunter. Many intelligent sportsmen, who enjoy the chase for its own sake, are coming to a realization of the scientific and economic waste involved, and by taking a little additional thought and care are providing the museums of their country with specimens that will be priceless memorials in time to come. For Canadians, or for sportsmen who enjoy the privilege of hunting in Canada, the National Museum of Canada is the legitimate repository of the zoological specimens they gather and which are not desired as personal trophies. Such acquisitions will be kept safely, the records preserved, and the specimens made available for scientific and educational purposes.

The small mammals of any district, with the exception of the commoner species of mice, squirrels, etc., are less well known than the larger mammals. Even the commonest forms may belong to local races of widely ranging species, and the particular forms inhabiting many regions are not definitely known. The smaller mammals, as a rule, are preyed upon by the larger carnivorous mammals and birds, and have developed secretive habits as a necessity for the preservation of their lives. The greater number of the small mammals are nocturnal and although their presence may be detected by different signs, such as the tracks in dust, mud, or snow, the animals themselves are rarely seen unless special methods are adopted for capturing them. It is safe to say that in any locality of varied topography there are to be found several species of small mammals whose very name and existence are unknown to more than one person in a thousand. Some small mammals are so secretive, and so very local in their habitats, that they may even elude for a long time the observation of a close student of natural history. For this reason there is a chance to discover new forms or species, and as so few districts have been studied thoroughly, there is an opportunity to obtain new records almost anywhere.

Though the study of the larger mammals, valuable commercially for flesh and skins, for purposes of sport, or for æsthetic reasons, is of obvious importance, and has been pursued in more or less sporadic ways from remote antiquity, the importance of the smaller, less conspicuous species is rapidly becoming recognized through the researches of modern science.

Many species of mammals that have no direct economic value as food, or for their fur or hides, are nevertheless often of enormous indirect importance. They must be recognized as beneficial or detrimental to the interests of man and if the latter, means must be taken to combat them. Ground squirrels, prairie dogs, pocket gophers, and other rodents have caused direct damage to grain fields, running into millions of dollars annually in some parts of the country. Rabbits, hares, and field mice frequently cause great damage to fruit trees and young forest trees. Coyotes, wolves, and mountain lions take a large toll of sheep, cattle, and horses, and large sums have been expended for bounties in combating them. House mice and rats are well-known destructive pests, and have been known to carry the germs of diseases to man and the domestic animals.

In addition to the obvious reactions on human enterprise of the species commonly classed as vermin, there are other relationships that are not so well known. Though it is commonly known to farmers, trappers, fur dealers, and naturalists that there are wide fluctuations in the numbers of various species of wild mammals and birds from time to time, the extent of such variations and their causes are not so well understood (Elton, 1924, Anderson, 1928, 1929, 1942). Many plagues of various species of field mice or voles have been recorded from North America, Europe, and Asia. In Arctic America lemmings and mice regularly reach the peak of abundance about every 4 years and this is followed by a rapid wiping out of nearly all the small rodents by disease. Arctic foxes and snowy owls increase in proportion to the lemmings and mice and fall away very soon after the depression in rodent life. The common snowshoe rabbit or varying hare has a very noticeable cycle of abundance, which reaches the peak about every 10 years. Muskrats and grouse show a similar but less-marked cycle, and various animals that prey on the others, such as lynx, red fox, mink, marten, etc., have parallel periods of abundance and scarcity. The small rodents have some local effect in settled regions, mainly in injury to agriculture, but in the wilderness their fluctuations have a tremendous effect upon the fur trade. As Elliot Coues once wrote: “They have one obvious part to play, that of turning grass into flesh, in order that carnivorous Goths and Vandals may subsist also, and in their turn proclaim, ‘All flesh is grass’” (Jordan, 1929, p. 397).

The inter-relations between these different forms of life present still deeper and more obscure problems, which unfortunately have not received the attention they deserve. Pathologists have devoted most of their time to the study of diseases that affect mankind directly, and have discovered the relation of mosquitoes to yellow fever and malaria, of certain of the trypanosomes to sleeping sickness, of hook worms and other biological agents to other pathological conditions, and of rats and ground squirrels to the spread of bubonic plague and other diseases. It is also known that certain species of snails are secondary hosts to species of flukes that live in the bodies of various kinds of wild and domestic mammals, and that many kinds of parasitic worms and their allies infest the internal organs of other animals, but only a small number of their life histories have been thoroughly worked out. The most lowly species of mouse or shrew may be hosts to various internal and external parasites, or bear trypanosomes in their blood that may work havoc on themselves and on other species that feed on them or on the same range.

The problems of wild animal life are so varied and interlocking that the co-operative studies of systematic zoologists, parasitologists, pathologists, veterinarians, and ecologists, extending over a period of years, are essential to the solving of some of the important questions. Only the barest beginnings have been made in the scientific study of most of these questions as they apply to a few species. The key to some of these problems is only to be found by intensive and numerous prolonged observations in the field, and may be discovered by some farmer, trapper, game warden, or naturalist who is observant and reports his observations.

It is generally admitted by naturalists that species closely resembling each other often have quite different habits and unlike relations to other species. Different strains, as in plants, may not be subject to the same infections and their periodic fluctuations may be different. Observations on animal diseases, or on animal parasites, lose much of their value if there is no certainty of the host, or species afflicted. Consequently, there must be a certain amount of systematic taxonomic study before detailed observations can be made along other lines. Valuable observations of a general nature may be made without drawing the lines of differentiation too finely, but in general there must be sureness of the names of the animals before much of scientific value can be written about them (Anderson, 1920).

At this point it may be well to warn against incompetent or careless identification. A casual or “sight” identification by an experienced naturalist who is familiar with the mammals of the district is of more value than one by an amateur. However, many forms are so obscurely marked that there is great chance for confusion, and specimens need careful examination in hand. In case of doubt the specimen should be preserved and the determination verified by an expert.

Though certain methods of preparing specimens have been well tried, and are preferable, circumstances may arise when variations are necessary. An inexperienced collector may not remember the details, and not be able to go by the book, but if a skin is preserved with no external parts missing, and the skull, feet, and leg bones preserved, it is not important that the cuts be made in a strictly orthodox manner. These details are more important in handling short-haired or hairless tropical mammals, but fortunately most of our Canadian species are well haired or furred, and the cuts may be sewn up later without serious detriment to the specimen. Rare and valuable zoological specimens do not grow on bushes, and the collector has to take them when and under whatever conditions he can capture them. When they come, they may be in larger numbers than can be handled properly and emergency methods must be employed. It may be necessary to abbreviate the preliminary work and finish the details later. As long as the specimens are complete, they may usually be remade in a more satisfactory manner.

For persons who may wish to preserve specimens for naming or for record purposes, a simple method is described here (page 7). The method of preserving flat or cased skins will also be found very satisfactory for collectors who may happen to obtain occasional specimens when they have a small amount of equipment and limited time. Collectors in remote districts or on long packing trips will also find the method useful, particularly when time and opportunity are not convenient for drying the ordinary type of so-called “scientific skin” or “study skin”. Persons who are making a large collection, and who are able to work under favourable conditions, will find that with some practice the conventional type of “skin” stuffed to approximate shape of the animal is easily and rapidly made, and more artistic and attractive. The flat skin, however, is of equal value for scientific purposes. In many ways, a good flat skin is superior to an over-stretched or poorly made stuffed skin. Study skins and flat skins may be mounted for exhibition at any later time. Specimens may be sent to the Curator, National Museum of Canada, Ottawa, who will have them identified and returned if desired.

Specimens are desired from all localities. The only absolute proofs for range of species are specimens actually taken and identified. Collections have been made in many parts of Nova Scotia including Cape Breton Island, northeastern New Brunswick, Gaspe peninsula, the north shore of the Gulf of St. Lawrence and southern parts of Quebec, parts of Ontario, southwestern and northwestern Manitoba and the Churchill region on Hudson Bay, the prairie region of Saskatchewan, southern, central, southwestern, and northeastern Alberta, southern British Columbia and considerable areas on the coast and in the interior of the same province, southwestern and southeastern corners and Arctic coast of Yukon territory, the coastal region of the Northwest Territories, and some of the islands of the Arctic archipelago. These collections are, of course, not complete for any locality, they merely represent little oases of investigation, and work in nearby areas might bring remarkable additions to our fauna.

The areas that have received less attention are central, southern, and western New Brunswick, Prince Edward Island, New Quebec (Ungava Peninsula), parts of northern and western Ontario, southeastern and eastern Manitoba, northern half of Saskatchewan, northwestern Alberta, northeastern British Columbia, certain areas on the Pacific coast and islands and in central British Columbia, the interior of much of Vancouver Island, central Yukon territory, and large areas in the interior of the Northwest Territories (districts of Mackenzie and Kee...