W. J. Hamilton

Defense of Space and Resources by Chacma (Papio Ursinus) Baboon Troops in an African Desert and Swamp

Baboons are not included in the growing body of documentation on primate spatial defense. Instead, most field studies of baboons suggest that troops occupy overlapping undefended home ranges. In southwestern Africa we found defense of space by two troops living in a Namib Desert canyon and by a population of troops on the Okavango Swamp flood—plain in Botswana. Two desert troops encountered one another at contiguous ends of their linear home ranges and established a defended boundary near a waterhole. One troop also dominated a third, a smaller troop at the opposite end of its home range. In the swamp, large troops, living in a more energy and plant species—rich environment, occupied small home ranges relative to troops studied elsewhere in Africa. Here space was defended along well—defined boundaries. Size and configuration of troop space and the arrangement of resources within each space influence the likelihood of intertroop encounters and the expression of spatial defense. See full-text article at JSTOR

Fog basking by the Namib Desert beetle, Onymacris unguicularis

THE Namib Desert along the south-western coast of Africa supports a sand dune fauna without counterpart elsewhere in the world1. The trophic base of the arthropod fauna is wind-blown detritus2. Aperiodic advective fog collection from vegetation3 or detritus4 is a possible source of water for diverse Namib animals. For the specialised fauna living in vegetation-less dunes, fog collection from detritus4, disturbed sand projections5, directly from humid air6, or from water precipitated on the body4,7, seem to be the only possible water uptake methods. Water uptake from saturated or subsaturated air, demonstrated for a few arthropod species6, is not a physiological capability of Namib tenebrionids already investigated4,6,7.

Omnivory and Utilization of Food Resources by Chacma Baboons, Papio ursinus

Chacma baboon omnivory is an adaptation to reduce intraspecific and interspecific competition for food resources. When available, animal matter was the most preferred food, and alternative foods were ignored. Fruits and seeds were second choice and leafy vegetation was least preferred. Under most circumstances the troop social structure and the morphology of baboons reduces predation risk and the need for watchfulness. Baboons consequently can spend long intervals processing food, thus enabling them to circumvent the antiherbivory adaptations of many plants. This enables baboons to utilize resources unavailable to some interspecific competitors.

Defensive stoning by baboons

REPORTS of the use of tools in offence or defence by wild animals is limited to accounts of chimpanzees throwing branches at conspecifics, potential predators and at human observers1. Anecdotal accounts of stone throwing by baboons2 have been dismissed on the basis of the unreliability of correspondents and the improbability of oriented throwing by a quadruped anatomically incapable of overhand throwing3. In spite of several years of field study elsewhere in Africa, often in rocky terrain, there are no reports by professional field observers of deliberate stone throwing by baboons4–7.

Anatomy for students

Dr. Eloise Gibletts outstanding book well illustrates the phenomenal extension of biological knowledge which has taken place in the last two decades. In the present context the development of sophisticated biochemical methods, in particular the electrophoresis of proteins in starch gel, has allowed enthusiastic biologists and medical scientists, including Dr. Giblett herself, to study the proteins of the blood in a way and depth that had never been possible before. The result has been the demonstration that many (perhaps all) of the proteins of the blood cells and plasma can exist in different molecular forms. Genetic polymorphism is familiar to everyone in respect of the redcell blood groups, but the fact that this is true also of so many of the other blood proteins may come as a surprise. Thus, for instance, in plasma the immunoglobulins, haptoglobin, transferrin, pseudocholinesterase, and alkaline phosphatase can all exist in several or many molecular forms, as can haemoglobin, glucose-6-phosphate dehydrogenase, and many other red-cell enzymes. More is perhaps known of the haemoglobin molecule and its variants than of any other protein. Whether other proteins exist in as many other forms is as yet unknown. Their study is in fact only just beginning; one practical difficulty is that unless a substitution makes a significant alteration to molecular size and charge a variant cannot be separated by electrophoresis. Bearing in mind this difficulty and the additional problem of working with proteins present in very small amounts (compared to haemoglobin), it is remarkable that Dr. Giblett has been able to list as many as 28 variants of glucose-6-phosphate dehydrogenase (G-6-PD). Fortunately not all these variants lead to clinical disability, and the same, of course, is true of many of the haemoglobin variants. The book consists of 17 chapters. Most of these deal with a single group of genetic markers; each is a self-contained review, and is splendidly organized and appropriately illustrated. In addition, each is provided with an index at the beginning and a comprehensive bibliography at the end. Many, such as those on Gm and Inv, haptoglobin, transferrin, and the Gc system, contain two bibliographies, a general one and a special one of papers dealing with geographical distribution. The last chapter, which is a short one, deals with the contribution which the knowledge of the blood genetic markers has made and is making to knowledge of human biology. The last point made is that much more is known of human variation than about the reasons for its existence. In particular, with a few notable exceptionsfor example, malaria and Hb-S and probably G-6-PD, the identity of the selective factors which have maintained the polymorphism of so many proteins remains largely unknown. There are some deliberate omissions which should perhaps be noted. Thus the white cell and platelet antigenic systems are not dealt with, and the chapters on the bloodgroup antigens and haemoglobins have been kept deliberately short and deal mainly with molecular structure and biosynthesis. In general, too, rare inborn errors of metabolism which affect less than 1-2% of the population are not discussed. Dr. Giblett is to be congratulated on her industry in bringing together so much new information on so wide and new a field in a single volume and for the care she has taken in its production. It is a book that all haematologists, serologists, and geneticists will wish to have close at hand in their personal library. As prices are nowadays, it is a bargain at 85s.

The Head and the Neck

This chapter discusses the structure of head and the neck in humans. A pair of rounded ridges is seen passing up the back of the neck in children and young adults, with a pronounced intervening furrow in the middle line. The ridges are formed by the semispinalis capitis muscles, covered by the thin sheet of the upper part of the trapezius muscle. In the adult, the groove between the ridges tends to become obliterated, but the semispinalis muscles are recognized on palpation if the head is extended against resistance. The pharynx is a space that lies behind the nasal cavities, the mouth and tongue, and the larynx. Three portions are, thus, distinguished as the nasal part, the oral part, and the laryngeal part. The shape and proportions of the head and face show striking hereditary differences, and it is mainly by these that an individual is recognized and the likeness of a portrait is appreciated. No two persons are exactly alike but the differences are very slight, as with identical or like twins. The face and head ordinarily show a slight asymmetry, which is mainly because of the effects of asymmetrical facial expressions and possibly also because of slight differences in the size of the two sides of the brain. Around the mouth, differences depend partly on the form of the facial skeleton and partly on the amount of superficial fat present. Gross disturbances of the posture of the neck may affect the growth of the face, as when the head is habitually held on one side on account of pathological shortening of the sternomastoid muscle. That part of the face which is on the side to which the head is inclined fails to grow as large as the other side.

The Human Skeletal Pattern

This chapter reviews the human skeletal pattern. Bone is a connective tissue, the matrix of which consists of bundles of collagenous connective tissue fibres 3–5 μ thick surrounded by an amorphous polysaccharide gel or ground substance in which crystals of a complex calcium phosphate salt are deposited. Two kinds of bones may be distinguished, namely, lamellar bone and fibrous bone. In the teeth, two modified forms of bone are found, namely, dentine and cement. A radiograph is a unique way of visualizing the fine detail of the calcified portions of the bones in the living person because it reveals details of internal structure. Some muscles and tendons are sufficiently dense or bulky to cast a shadow of low density, which are distinguished from the shadow of the skin and other soft tissue structures. An example is the tendo calcaneus. As a rule, they are demonstrated in radiographs taken especially for this purpose better than in those taken to show the bones.

The Upper Limb

This chapter discusses the anatomy and movement of the upper limb. The general form of the shoulder and upper limb is determined primarily by the skeleton, but most of the detail is provided by muscles and tendons. On account of the extensive movements that take place at the joints, the relative positions of the various skeletal structures differ greatly in different postures. Movements of the shoulder girdle ordinarily involve movements both at the shoulder joint and between the shoulder girdle and chest wall. The shoulder girdle movements alter the orientation of the glenoid cavity of the scapula and, thus, modify the position of the limb. The position of the limb, thus, depends both on the position of the girdle in relation to the trunk and on the posture at the shoulder joint. Movements at the elbow joint comprise flexion and extension of the forearm. Flexion is limited by the contact of the soft tissues of the forearm and arm and by contact of the head of the radius against the humerus, extension by the tension of the brachialis muscle, or sometimes by the contact of the olecranon with the olecranon fossa of the humerus.

The Lower Limb

This chapter discusses the anatomy and movement of the lower limb. The general outline of the buttock and thigh is determined by the form of the pelvis and femur, together with the covering muscles and accumulations of fat. The crest of the ilium gives form to the junction of buttock and loin, the symphysis pubis forms the medial end of the groin, while the greater trochanter produces a prominent lateral convexity at the junction of buttock and thigh. The forward curve of the shaft of the femur determines the general form of the thigh. The positions to which the distal end of the femur is displaced by movement at the hip joint lie approximately on the surface of a hemisphere, the radius of which is represented by the length of the femur. The movements are flexion, extension, adduction, and abduction. The general form of the knee is determined by the patella and the condyles of the femur and tibia. The outlines of the skeleton are partially concealed by soft tissues, by masses of fat and to a smaller extent by muscle tendons or muscles. The chapter provides an overview of lower limb lymphatics. The lymphatics of the leg are demonstrated after the injection of a suitable contrast medium into one of the small lymphatic vessels on the dorsum of the foot, which is identified by injecting dye between the webs of the toes.

The Vertebral Column

This chapter describes the vertebral column, which is a flexible structure made up of vertebrae and intervertebral discs. Small alterations of form accompany changes in the distribution of the bodyweight, while greater alterations take place in general movements of the body. The numbers of vertebrae in the various regions into which the vertebral column is subdivided are cervical 7, thoracic 12, lumbar 5, sacral 5, and coccygeal 4. Either the 7th cervical or the 1st lumbar vertebra bears an additional pair of ribs. The cervical ribs are short and only detected on radiological examination, but they are longer and palpable in the supraclavicular fossa of the neck. In a small proportion of subjects, there are only four lumbar vertebrae, while the absence of a 12th rib or nonfusion of the first sacral segment suggests the presence of six lumbar vertebrae. Exceptionally, a half vertebral body may be interposed between the bodies of adjacent vertebrae on one side. In the condition of spina bifida, the neural arches are incomplete dorsally. This bony defect may be accompanied by anomalies of the spinal cord. It is not unusual to find minor degrees of the condition in the sacrum and the neural arch of the 5th lumbar vertebra, and these are usually without significance.