Prominent Authors & Literary Milestones

Robert L. Rausch, (1921 - 2012)



D.V.M., Ph.D. Professor Emeritus
Department of Comparative Medicine
School of Medicine
University of Washington
Seattle, WA 98368


Primary research includes zoonotic diseases and the natural history and taxonomy of their mammalian hosts. Field and laboratory investigations have emphasized various diseases, including rabies, brucellosis, and tularemia, that affect indigenous peoples in the Arctic and Subarctic. Since 1950, sustained research has concerned cestodes of the genus Echinococcus, each species of which causes a distinctive disease in people. Investigations begun in 1950 on St. Lawrence Island (Bering Sea) led to recognition of E. multilocularis as an independent species, resolving a century-long controversy as to the etiology of alveolar echinococcosis, and to elucidation of the natural cycle of that cestode. From 1970 to 1996, in collaboration with physicians at the Alaska Native Medical Center (Anchorage), investigations concerned methods of diagnosis, chemotherapy, and prevention of alveolar echinococcosis. Related studies were also undertaken in the field in Japan, People's Republic of China, and NE Siberia (in collaboration with V. R. Rausch). Since 1950 also, the investigation of cystic echinococcosis has been conducted concurrently. In 1972, a neotropical species, E. vogeli, was described by Rausch and Bernstein from a wild canid, Speothos venaticus, captured in Ecuador. In collaboration with A. D'Alessandro, Tulane University, and V. R. Rausch, the cycle was defined during the late 1970's in Colombia. Polycystic echinococcosis caused by that cestode is now known to be a severe disease occurring in people in northern countries of South America, and as far north as Panama. A project in progress since 1949 concerns cestodes (Diphyllobothriidae) transmitted from fishes to people and other mammals, and to piscivorous birds, mainly in the northern hemisphere. Several new species, some occurring in people, have been described in Alaska. Basic investigations on the taxonomy of helminths and of mammals are continuing.



For over a century, scientists recognized several North American brown bear subspecies. That changed in 1953 when biologist R.L. Rausch designated all brown bears not living on Alaska's Kodiak, Afognak and Shuyak islands as grizzlies. Kodiak bears remained Ursus arctos middendorffi, which means "Middendorff's northern bear."


From On the Status of Some Arctic Mammals, limited text extract:

The specific status of North American grizzly bears is one of the most complex problems of mammalian taxonomy. The difficulty stems directly from the work of Merriam (1918), who concluded that there are 86 forms of grizzlies (and brown bears) in North America. He stated: "One of the unlooked-for results of the critical study of the American bears is the discovery that the big bears, like mice and other small mammals, split up into a large number of forms whose ranges in some cases overlap so that three or more species may be found in the same region" (p. 9). Such a view is not tenable, but evidence to the contrary is not easily secured.
The grizzly has been exterminated over much of its former North American range. Although it still exists in considerable numbers in Alaska, the problem of obtaining adequate material for study is nevertheless serious. The killing of bears for scientific purposes cannot often be justified, because of the rapid reduction of their numbers now being brought about through sport hunting. I have been fortunate, however, in securing 22 skulls, several with skins, from the central Brooks Range region. Full data on sex, date, and place of capture have been obtained. Additional specimens from various other localities within the Territory have also been assembled and pertinent material in various public and private collections has been studied.

From this material, I have concluded that a single, but highly variable, species of grizzly bear occurs in Alaska, and I shall endeavor in this paper to substantiate this conclusion. The extreme degree of individual variation demonstrated by the Brooks Range specimens is considered particularly significant.

In assigning specific names to various specimens of grizzlies which he obtained, Merriam failed to take into consideration any possibility of individual variation. Some "species" were named on the basis of a single skull, and in some cases not even the sex of the animal was known. Simpson (1945) has appropriately remarked that: "С. H. Merriam distinguished about 90 species of North American bears alone, but he had a (fortunately) unique conception of the character of a species, giving it less scope than most authors give a minor geographic race, not much more than an individual genetic family group. On such a system twin bear cubs could be of different species." (p. 225, footnote).

Further, Merriam's system of bear classification was based upon the hypothesis that the "species" of bears occurring in the same region maintain their identity by segregated breeding. In reference to this, Merriam (1918, p. 8) stated: "Some writers have advanced the view that the various species of bears freely interbreed. Let those so minded ask themselves the question, If promiscuous interbreeding were to take place, what would become of the species?". It would seem that Merriam concluded a prior that the species existed, and then went about finding means to support such a conclusion.

It is difficult to obtain much data on the breeding habits of bears. Most animals coming under close observation are usually seen over the sights of a rifle, and rarely live long, enough to carry on their normal activities. Murie (1944) described the mating activities of two physically different male bears with a single female in the Mount McKinley region. Anyone working in a place where grizzlies still occur will soon note a lack of uniformity in the physical characteristics of the animals. Grizzlies, particularly males, travel considerable distances. This, together with their low density in most regions, suggests that breeding occurs on a chance basis alone. Under the stresses of breeding time it is most unlikely that bears are very selective in their matings, but rather that they must copulate according to opportunity. This is a fundamental concept which I adopt as valid. If one must wait until a large series of grizzlies, collected after having been observed in coitu, has been assembled, the problem is hopeless. If my conclusion that the grizzlies of Alaska represent but one species is valid, certain generalizations are possible.

It seems necessary first to consider separately the various characteristics used heretofore to differentiate species of grizzlies, in the light of a broader species concept.
External characteristics

Size: Grizzlies in Alaska vary greatly in size, even in the same locality. Over the Territory as a whole, the largest animals occur on Kodiak Island and the Alaska Peninsula. In other regions the adult bears vary in size between rather broad limits. In the Brooks Range, where I have made the most observations, the adult bears range from about 400 to 700 lbs., the latter weight though is rare. Such a size range appears to be characteristic of grizzlies over most of interior Alaska. Specimens from southeastern Alaska have not been considered in this study.

On Kodiak and Afognak islands, and on the Alaska Peninsula, the species attains its greatest size in North America. Extremely large animals are becoming scarce as a result of incessant hunting pressure, but specimens weighing from 1,200 to, perhaps, 1,500 lbs. are still killed occasionally. The maximum weight attained by these bears is not known, but the greatest reliable weight of which I know is 1,200 lbs. Weights exceeding 1,500 lbs. are frequently reported, but these are estimates and cannot be considered accurate.

The largest grizzlies in a given region are males, but some females exceed small males in size. There is rarely size-uniformity in a grizzly population. The majority of animals may be of about the same size, but unusually large and unusually small individuals are seen. Size depends in part upon age and condition. After full growth is attained, an individual bear varies in weight according to the season of the year, depending upon the amount of fat present. Very old animals, usually with broken and badly worn teeth, are often in poor condition, and in general have the lowest weights.

Measurements of external proportions of bears are so few that they have little or no value at present. Age, size, and sex all influence the various dimensions. Sport hunters regularly measure the length and width of the green hide.

I have made a few observations on these measurements, which confirm the obvious conclusion that they are worthless for scientific purposes, since they reflect only the enthusiasm and strength of the hunter and his guide.

It is noteworthy that maximum size in Ursus arctos is attained where an unlimited supply of high protein food is available. Thus, on Kodiak and Afognak islands, and, to a lesser degree, on the Alaska Peninsula, heavy salmon runs provide food during all of the warmer months when the bears are active. On Kodiak Island, the red salmon (Oncorhynchus nerka (Walbaum)) is available from late June to late September in the streams, and from late May at least until late November along the lake shores. Other species are abundant for shorter periods during the summer months. The same situation exists in Asia. In northeastern Siberia, particularly Kamchatka, great salmon runs occur. Here also U. arctos beringianus attains the largest size of any Eurasian form of U. arctos. For this form, Bobrinskiy et al. (1944) gave a maximum skull length of 445 mm. According to Johnson (1947) this bear attains a weight of 560 kg. in winter.

Colour: The colour of grizzlies is highly variable and, in my opinion, it has little or no taxonomic value. In the Brooks Range grizzlies range in colour from very pale (near Ridgway's Ivory Yellow,1 but paler) to nearly black (near Blackish Brown). Some animals are entirely light-coloured, except for the legs and belly, but most have the buffy colour restricted to the head, shoulders and back. Despite the great range in colour, the general pattern is essentially the same: head and shoulders lighter, back and sides dark, belly dark, and legs and feet darkest. Even the very pale specimens have dark feet and legs, usually with a reddish tinge. It is true that the bears of a given region may be of predominantly one colour, but lighter or darker specimens are almost always observed. The bears of the Alaska Peninsula and Kodiak-Afognak may, in general, be more uniformly coloured, but on Kodiak Island I have examined specimens as light-coloured as any observed on the mainland, while others are very dark.

Claws: Grizzly claws are very variable in shape, size, and colour. Shape (curvature) and size depend mainly upon season of the year. Animals killed in the early spring usually have long, well-formed claws, but later they become badly worn through use. Extent of wear depends upon the terrain, rocky soils causing more rapid wear than others, particularly in places where bears frequently dig for rodents. When other food (e.g., salmon) is available, less wear results. Claw shape and size also appear to vary individually.

Glaw colour varies from white to nearly black, and is related to some extent to the degree of pigmentation of the fur. Very pale-coloured bears in general have white or very light claws.
Internal characteristics

The skull: The differentiation of grizzly "species" has been based mainly on skull characters. Among these, skull size, relative proportions, and details of dentition have been considered important. Merriam (1918, p. 13) stated: "Cranial and dental characters among the big bears are very subtle. As a rule comparison of any two skulls of essentially the same size brings to light so many resemblances that one is likely to infer a far closer relationship than actually exists. This is because the big bears of the genus Ursus are such a closely interrelated group that the resemblances far outnumber the differences. Hence the greatest caution is necessary to avoid misleading conclusions."

The paucity of good series of bear skulls with complete data from any one region has in part prevented an evaluation of individual variation. However, even when good material has been available, the problem of variation has been little considered. Regarding the Alaska Peninsula bears, Merriam (1918, p. 125) stated: "Skulls of adult males which it seems necessary to call gyas present a surprisingly wide range in size and form. Among them are three quite different types which if isolated would undoubtedly develop into very distinct species." Merriam did not state why, in this case, he considered such "different types" to be conspecific. On the other hand, he considered U. kidderi kidderi Merriam, which has the same range as U. gyas, to be specifically distinct despite his statement: "Males of kidderi are sometimes hard to tell from females of gyas. .. (p. 107)". As far as I can determine, a single form, showing the usual variability, is found on the Alaska Peninsula. Its status is discussed in more detail below.

Bears occurring on Kodiak Island, hitherto known as U. middendorffi Merriam, are also quite variable. It is true that large adults show cranial characteristics which are relatively constant, but nevertheless some individuals differ strikingly from such "typical" specimens. I have examined a large series of skulls of this form, and Allen (1903b) studied 30 skulls of Kodiak bears and summarized their measurements. This form is likewise considered further below.

A small series of bears from the Alaska Range, designated as Ursus toklat Merriam, is in the collection of the U.S. National Museum. The skulls which I have examined have been relatively uniform, but show minor structural differences. The bears of the Mount McKinley region have been observed by several workers in the field, and nearly all of them have remarked on obvious physical differences.
The most significant bear material I have obtained consists of 22 skulls, with full collecting data, from arctic Alaska. These specimens, taken in the Brooks Range, exhibit unusual cranial variation. Some brief remarks on variation in Brooks Range bears were included in another paper (Rausch, 1951), under the species name U. richardsoni Swainson. Among these skulls, several adult male specimens differ conspicuously from one another, despite their having been killed in the same general region. Four specimens of unusual interest are shown in Fig. 3, and their measurements are given in Table I. All but one of these bears (orig. No. 9849; U.S. Nat. Mus. No. 293782) were killed in the Anaktuvuk Pass region of the central Brooks Range. They probably comprised interbreeding members of a single population. These animals, mature or aged males, were among 35 bears killed over a period of five years in the Anaktuvuk Pass region.


According to Merriam's system of bear classification, it would be acceptable to consider each of these 4 animals representative of a different species. I am convinced, however, that such is not the case. In another paper (Rausch, 1951, p. 165), it was stated, regarding the Alaskan distribution of U. richardsoni, that it "is widely distributed, and in Alaska its range appears to encompass at least the entire region north of the southern limits of the Brooks Range, including the Arctic Slope." It is necessary here to discuss also some of the species recorded from farther east, particularly in northern Canada.

In 1949 I studied pertinent bear material from arctic North America which has been deposited in various museums. Dr. R. M. Anderson kindly reviewed with me much of the material in the collections of the National Museum of Canada, among which were the type of U. internationalis Merriam, a large series of U. richardsoni which had been collected by Dr. Anderson, and a series of U. macfarlani Merriam. The study of this material and comparisons with Alaskan specimens led to the conclusion that all were con-specific. This was substantiated by the study of material in the U.S. National Museum, and in the American Museum of Natural History. Further work in Alaska has supported this conclusion.

As a result of the earlier work, it was concluded that a single species of bear extended across the entire North American Arctic. The variation observed in the Brooks Range bears has permitted a better concept of normal individual variation in grizzlies, and other Alaskan "species" may now be considered.

The comparison of my material with single specimens supposedly representing different species obviously had little value, since it was not possible to distinguish specific differences from individual differences. Where small series were available, as with U. toklat Merriam, from the Mount McKinley region, and Ursus sp. from Jarvis Creek, only small inconsistencies were sometimes noted. In light of observations made on the Brooks Range specimens, such differences cannot be considered significant. Moreover, the examination of miscellaneous specimens from Alaska south of the Brooks Range has failed to disclose anything to support the concept that any of these differ specifically from the more northern specimens.


On the Status of Some Arctic Mammals (1953) PDF LINK: pubs.aina.ucalgary.ca/arctic/Arctic6-2-91.pdf




Also....



Abstract

Variation in size of brown bears, Ursus arctos Linnaeus, indicated by condylobasal length of the skull, has been studied in 357 specimens comprising series from 26 regions in North America. These were selected by criteria defined from a previous study of growth in black bears, U. americanus Pallas, since it was determined that the growth pattern is essentially the same for the two species. Variation in mean condylobasal length in the series studied is clinal; a well-defined gradient exists along the coastal zone from Bella Coola, British Columbia, to the end of the Alaska Peninsula, with mean condylobasal length increasing from south to northwest. A similar gradient was evident along the Arctic Coast, beginning in the region of Coronation Gulf. In the interior, small mean values were obtained for samples from the western Yukon Territory, with mean size increasing toward both the southeast and the northwest. It is concluded that formal recognition of segments of intergrading populations of brown bears at the subspecific level is not justified. Brown bears on Kodiak–Afognak–Shuyak Islands comprise a reproductively isolated population possessing distinctive cranial characteristics, and to them the name U. arctos middendorffi Merriam is applicable. It is proposed that U. a. horribilis Ord be used for brown bears over the greater part of the range of the species in North America. The number of subspecies of U. arctos recognized in Eurasia also may be reduced, with the study of comparable series of skulls.

GEOGRAPHIC VARIATION IN SIZE IN NORTH AMERICAN BROWN BEARS, URSUS ARCTOS L., AS INDICATED BY CONDYLOBASAL LENGTH (1963) PDF LINK: www.nrcresearchpress.com/doi/pdf/10.1139/z63-005


Update: On October 6, 2012, Robert L. Rausch passed away at his home on Bainbridge Island, Wash. His obituary can be read here: link.