An unusual, and admirable, feature of the book is its emphasis on fact and observation rather than theory. Every kind of biological investigation -physiological, anatomical, behavioural or evolutionary – is enlisted to support the “naturalness” of the book’s concepts and propositions. The first half is an account of gamete formation, conception, implantation, fetal development and growth, and the process of birth described vividly from the point of view of the fetus. The book draws freely and entertainingly on images and measurements recently made possible by technology, such as antenatal scanning and in vitro fertilisation, and, ignoring a few half-truths and oversimplifications, is up to date and accurate. Elaine Morgan draws attention to the many curious features of human reproduction and infancy that are not easily explained in functional or evolutionary terms.

The second half of the book deals with the acquisition of human physical, intellectual and social skills. She draws upon studies of family life among indigenous peoples and wild primates and discusses the fascinating notions that emerge from attempts to teach chimpanzees to speak and reason. The result is a biological critique of modern perinatal care, family structure, educational and penal policy, and feminism. The message is that the roles of parents, especially mothers – and especially during early development – are central to children’s healthy physical, intellectual and emotional development and cannot safely be substituted or abbreviated.

Morgan’s enthusiasm for her work is infectious, and her broad reading and vacuum-cleaner mind have collected some delightful titbits of information that would have been excluded from more straight-laced learned works. But to scientists devoted to considering all sides of an argument and addressing contradictory as well as supportive facts, there is always a whiff of the Just So Stories about her choice of facts and the glib way in which she marshals them in support of her train of thought. Thus several points, some well substantiated, some much less so, are presented in support of the aquatic ape theory of human evolution (she has written three books on this theme), with hardly a mention of the large body of evidence that refutes it, or of the many reputable scientists who remain unconvinced by it.

This book will entertain the general reader, and may inspire some to study biology in greater depth. Whether it will achieve its aim of influencing political or economic events is less certain: attempts to derive social policy from biological concepts are always risky and can be disastrous.

‘Parrots,’ wrote George Bernard Shaw, ‘are amusing and never die. You
wish they did.’ Unfortunately they are dying. Species of the order Psittaciformes
are becoming extinct at a rate faster than any other group of bird except
the Galliformes. It is their amusing habits that are killing them. Like
humans, most parrots are intelligent, sociable, long-lived, slow-maturing,
slow-breeding and parental care is elaborate and critical to the offsprings’
success. They are also fussy about their choice of mate. These habits make
them endearing as pets but susceptible to habitat destruction and overcollecting
as well as being difficult to breed and raise in captivity.

Pet keeping is a long-established human habit, not least among native
Americans. The Kalapalo Indians of Brazil and the Barasana of Colombia spend
hours playing with their pets and teaching them to talk. Parrots were among
the first items to be traded with European settlers and merchants, and for
centuries these colourful, amiable birds have been valued as pets in the
western world. Psittacines have many qualities that make them ideal for
pets in an urban society: their fecundity is easily controlled and, unlike
cats and dogs, they do not foul streets, harass wildlife or attack children.
Although a few species have established feral populations, often following
introduction long ago by native peoples, they are not as destructive to
indigenous fauna and flora as many introduced mammals.

Contrary to the impression created by the title, this book is far from
a simple catalogue of destruction and despair. It summarises the current
situation in clear, non-polemical language, freely admitting when information
is inadequate or biased, and includes thoughtful discussions of ways to
combine parrot conservation with the social attitudes and economic needs
of an ever-expanding human population. Topics range from public education
campaigns aimed at conserving species endemic to the Lesser Antilles, to
psittacine destruction of crops in Argentina, and ecotourism involving macaws
in Peru.

To safeguard the biologically valuable species and the lucrative trade,
the whole process from collector of wild birds to pet or menagerie owner
needs to be made more efficient and responsible. Many such improvements
are simple and arise from a knowledge of the basic biology of the species.
For example, in nearly all psittacines, mortality is naturally high among
nestlings and juveniles and so newly fledged parrots could be harvested
in significant numbers with minimal impact on the species’ abundance and
long-term viability.

Present harvesting practices are incredibly wasteful: often the tree
containing the nest-hole is cut down to extract the nestlings, creating
a shortage of nest sites, and the entire clutch is collected instead of
leaving one or two for the parents to raise. The chicks are harvested when
too young and fail to thrive on an artificial diet. For some species, there
seems to be scope for increasing the wild population simply by erecting
more suitable nest boxes.

Holding and transportation conditions are also poor, and mortality in
transit is unnecessarily high. Smuggling and dyeing feathers to disguise
a restricted species add to the birds’ suffering. Although many land-owners,
collectors and dealers are well aware that they are exploiting their product
to extinction, they are reluctant to be the first to implement restrictions
on harvesting, or go to the extra expense of improving efficiency in maintenance
and transport.

Two main messages emerge repeatedly from almost every chapter. First,
we do not know enough about parrot biology – for many species, particularly
some of the rarest, basic information about diet, breeding habits and life
expectancy is minimal. Secondly, all attempts at controlled exploitation
could be easily and disastrously undermined by dishonesty and illegal practices.
Except in the case of a few species that breed readily in captivity, zoo
or ranch breeding is not seen as a realistic solution in the long term.

In most cases, the editors are co-authors, often with several others.
Each chapter begins with an English abstract and ends with the same abstract
in Spanish, thereby making the book accessible to most Latin American readers.
Biological and economic facts and figures are presented as tables and diagrams,
and the entire text is thoroughly indexed. Numerous up-to-date references
drawn from the scientific as well as the zoo and conservation literature
are included and make up the other half of the chapters, although compiling
them as a single list would have avoided much unnecessary duplication. Repetition
is also a problem with the main text: it would be easier to read from cover
to cover if the editors had integrated the chapters more thoroughly.

One chapter is an edited transcript of a discussion that took place
in June 1990 between members of the American Ornithologists’ Union and
more than a dozen ‘distinguished experts in psittacology’. The chapter
refers briefly to the suitability of different parrot species to conditions
in captivity. A thorough discussion of this important topic is, to my mind,
the most significant omission from this book. Most consumers just want an
affectionate, teachable companion bird, regardless of its origin or conservation
status in the wild. But aviculturists collect exotic birds because they
are rare and spectacular, even if their habits make them difficult to maintain
in good health and unrewarding as pets. If importation were effectively
restricted or banned, most, possibly all, of the pet market could be satisfied
with specimens bred from only those species that prosper in captivity. Initially,
such birds would be more expensive than wild-caught ones, but higher prices
could be a good thing if they encourage more responsible ownership. Collecting
rare species in private menageries is much more wasteful and has a far greater
impact on wild populations.

Caroline Pond found a stray parrot in Oxford in 1975. They have lived
happily together ever since.

Flying in purposefully, the pigeons select the perches that offer a
bird’s-eye view of the scene and scrutinise the audience with a beady, knowing
gaze. During meal breaks, they stride around, pecking at very unfamiliar
object and gobbling up titbits. They’re eager to impress: the slightly interest
from a potential sources of satisfaction, and they puff themselves up for
a frenzy of extravagant bowing and twirling, accompanied by well-meant but
incoherent cooing.

The object of such attention may be surprised, even alarmed, bu such
effusive displays of uncritical admiration. ĐÓ°ÉÔ­´´s just don’t behave
like that – well, not in public anyway. But publicity is the business of
pigeons – they’re willing to do anything, anywhere.

Their bemused victim may try to run, or hide, the more devious may try
to foist their suitor onto an unsuspecting colleague, but some succumb.
The triumphant consort shepherds its conquest into a quiet corner, buys
a round of drinks and .. well, you’ve read their bastard offspring in New
ĐÓ°ÉÔ­´´s.

The best-equipped and most persistent get the best stories. Darwin was
quite clear on this point: the sleekest suits, the loudest coos, and most
exaggerated bows, and, dare I mention it, the pinkest stockings, procreate
the most verbiage. Birds of a feather flock together, and competition between
rivals is an integral part of the process.

Top of the pecking order are the television journalists, who descend
upon their learned conversations with a barrage of questions with the same
brashness as a squadron of Trafalgar Square pigeons demanding (and getting)
sandwiches from flocks of tourists. The commotion attracts others, but interlopers
and even curious bystanders are chased off with threats and squawks.

The humble report with a shorthand notebook usualy forages alone, waylaying
stragglers and politely soliciting crumbs of information, while keeping
an eye open for distractions and rivals.

AS soon as choice morsels become scarce, the pigeons home with impressive
speed and spew out the partially digested pickings into hungry editors’
mouths. The squabs are as uncritical as they are ugly and uncouth: anything
and everything is stuffed down their throats, and they immediately beg for
more. The scientists’ hard-won data and cherished theories may be macerated
to an indecipherable muddle, but at least the newspapers and magazines grow
fat on it.

Caroline Pond writes about science and does research in biology at the
Open University.

THERE ARE more than a million different kinds of animals, and probably
nearly as many ways of teaching zoology. This book is the view of one distinguished
zoologist – R. McNeill Alexander – of his subject. It is an amalgamation
and abbreviation of two of his previous books, The Invertebrates and The
Chordates: about 300 pages are devoted to invertebrates, and 200 to chordates.

Animals, though, is not a traditional textbook: taxonomic and morphological
terms are kept to a minimum and there are very few tables and no summaries.
Nor does it necessarily emphasise the sort of facts required for examinations.
On the other hand, the book is not a monograph and does not develop any
particular theme or point of view, beyond that of the author’s wide-ranging
interest in the structure and function of animals.

The first chapter is a brief account of some of the experimental methods
and concepts that feature prominently in later chapters. Each of the other
chapters begins with a brief summary of the classification of the animals
described in it. On the whole, there are few surprises in the taxonomic
scheme that Alexander adopts, although not every zoologist would discuss
sponges and cnidarians under the same heading, or group rotifers with roundworms.
Most of us find the notion of a phylum Arthropoda too useful to be abandoned.

Chapter titles follow a trad itional scala naturae, starting with protistans
and ending with mammals, and phylogenetic relationships are mentioned in
several places. Despite this, the author’s Cambridge roots are much in evidence,
and the main themes are functional and physiological.

The chapters start with brief accounts of some general points about
the structure and habits of the phylum or class. They continue with one
or more ‘stories’, some involving several diagrams and much experimental
detail, on aspects of the anatomy, physiology or development of the group
that the author finds interesting.

Alexander finds a wide variety of topics interesting, and the bulk of
most of the chapters consists of such stories. They range from the evolution
of sex, reproductive strategy in flatworms, the fine structure of molluscan
muscles, eye movements in crabs, the embryological origin of the coelom
to several topics in vertebrate palaeontology.

Some of these topics, such as the behaviour of sea anemones and insect
moulting hormones, have featured frequently in biology texts during the
past 25 years, but others such as those on fish and dinosaurs are new, or
at least have an original slant. All are relentlessly zoological: the book
barely mentions plants and microorganisms, even in connection with insects
and ruminant mammals.

In many of the stories, Alexander includes numerical data and details
of the elementary mathematical manipulations we use to analyse them. Surprisingly,
though, in view of the author’s contribution to biological theory, the book
concentrates on observations and experiments and there is very little theory.

Although the emphasis on developing special topics reflects accurately
how biological knowledge accumulates – certain aspects of certain species
are studied in great detail, while even the most elementary facts are lacking
for many others – inexperienced and less able students may find it confusing
and frustrating. To get the most out of this book, the reader should already
be familiar with the principles of classification, evolutionary biology,
ecology, physiology and genetics.

Abbreviating a text is always difficult and everyone has different priorities
about what should be retained. However, in many places, the text is shortened
too much from the previous versions. The arachnids fare particularly badly.
Although they and the horseshoe crabs have a whole chapter to themselves
in The Invertebrates, these familiar and economically important animals
feature only as a few brief notes and a couple of rather uninformative diagrams.
I was sorry to see the numerical information on silks and web construction
omitted; and acarines (ticks and mites) cause too much trouble to humans
to be dismissed in a few lines.

All the illustrations are drawings, mostly from The Invertebrates and
The Chordates. Unfortunately, reproduction of some of them, particularly
those taken from other sources, is less successful here than in the previous
books. Many of the drawings would be improved by more information about
the natural size and orientation of the subject, and by more consistent
styles of labelling. In some figures, it is difficult to see the details
mentioned in the text.

One of the most useful features are the classified lists of ‘Further
reading’ at the end of each chapter. These lists include original papers
and monographs, and may cover more than two pages and include up to nine
headings. The index consists mainly of names of species and other taxonomic
terms, both scientific and common. It is patchy on organ systems and other
terms; thus the entries for ‘eye’ and ‘muscles’ do not include any references
to vertebrates, even though both tissues feature on many of the diagrams,
and muscles and movement of both fish and tetrapods are discussed at length.

The writing style is conversational, with short paragraphs and numerous
asides and bits of information oblique to the main theme, but again many
of the most enjoyable aspects of the previous books are lost in the abbreviation.
The shorter, more comprehensive book was intended to appeal to a wider,
less specialised readership. However, the lack of emphasis on economically
important aspects of zoology (that is, parasites, crop pests, arthropod
vectors of diseases and food animals) make this book less useful for students
of applied biology, agriculture and medicine. Its style and pres entation
may prove unsuitable as an American-style course text.

Nonetheless, Animals will be useful as a source of information and ideas
for essays for students of zoology and biology. I am sure I will find it
useful for reference, but I am definitely keeping my old copies of The Invertebrates
and The Chordates.

Caroline Pond writes texts on comparative and evolutionary biology for
the Open University.

LIKE DARWIN and many biologists after him, Michael Crawford and David
Marsh are puzzled about the contributions of random genetic change and environmental
influences to the course of evolution; the aspect of the environment that
most concerns them is food. Food, particularly dietary lipids, is claimed
to be the ‘driving force’ in the evolution of animal form especially that
of the brain, vascular system and the skeleton. Organisms rely on various
lipids as both sources of energy and structural materials, and must obtain
some kinds of lipids from the diet.

The book provides some examples of nutritional explanations for the
course of evolution. One such is the evolution of flight in birds and bats,
which the authors regard as too complex, and the parallel evolution too
precise, to have arisen by established evolutionary mechanisms. Instead,
they propose that a taste for insects deficient in calcium and nectar led
to the evolution of pneumatic bones and flight: ‘Was this change (the evolu
tion of bat wings and dolphin flippers from forelimbs of land mammals) directed
by a coincident set of genetic mutations . . . or was there feedback between
the natural and physical environment resulting in a change of genetic expression
and finally in an alteration of the genetic codes?’ (our italics). As well
as being physiologically fanciful, this notion does not accord with the
palaeontological facts: ‘Perhaps we forget what the world looked like before
there was anything (ie any flying vertebrates) to eat the insects of the
air.’ No such world ever existed, even briefly; the principal predators
on insects are – and always have been – other arthropods, particularly arachnids.

The chapter ends with that well-known evolutionary teaser, the giraffe’s
neck. The authors point out that the neck of the female giraffe is shorter
than that of the male; he can obtain more food by browsing from taller trees,
although, as in most other species, most of the nutritional burden falls
on the female. But necks do more than reach into tall trees; a long one
may be a positive disadvantage for drinking from pools or running through
dense vegetation but it may be invaluable where it really counts, securing
a mate.

Crawford and Marsh do not consider sexual selection here and barely
mention it elsewhere. Indeed, coyness about all matters connected with choice
of mate and sexuality is one of the main ways in which the authors reveal
their lack of familiarity with the modern literature on evolution.

The centre piece of the book is entitled ‘The Favoured Predators’. Its
thesis is that flesh-eating promotes the evolution of large brains, fatty
paws and night vision that are denied to herbivores because their diet is
deficient in certain long-chain fatty acids. Comparing the genome to a computer
with limited disc space, the authors propose that the evolution of complicated
animals was made possible by their increasing reliance on nutritional sources
of complex molecules for which the genetic codes could therefore be lost.

We find this argument totally unconvincing. Geneticists and molecular
biologists report that much, and in some species most, of the nuclear DNA
appears to be redundant. Natural diets are also much more varied than the
authors imply; most ‘herbivores’ will eat carrion and the odd egg, snail
or insect larva if they find it. There is no compelling evidence that lipids
are limiting; the fact that diets deficient in lipids cause stunting does
not mean that gluttony causes hypertrophy or that such experiments have
any bearing on evolution.

Crawford and Marsh cite the origin of hooves as an example of substrate-driven
evolution, that is, a process driven by diet or environment. Eutherian carnivores
have paws, of course, and many hunt by stealth rather than stamina. Ungulates
have hooves and are herbivores, and run away, often very fast, when ambushed.
A few predators, notably cheetahs and hunting dogs, can outrun their prey
on flat ground. Ignoring the literature showing that the cheetah’s speed
is due mainly to flexion of the spine and shoulder rather than the feet,
the authors reject the theory that hooves evolved as an adaptation to fast
running. Hooves they claim, evolved for economy, not speed. ‘Hands and claws
need . . . long-chain fatty acids, the carnivores can get them but the herbivores
cannot’. Most rodents and many larger herbivores, including gorillas and
gelada baboons, and grazing and browsing marsupials such as kangaroos, tree
kangaroos and koalas have paws or feet padded with adipose tissue. Need
we say more? The central issue of the chapter ‘Apes, Dolphins and Men’ is
the evolutionary origin and nutritional requirements of large brains, particularly
that of Homo sapiens. The authors assume bigger is better, and their (unstated)
definition of intelli gence has a decidedly anthropomorphic bias. They reiterate
the arguments, most of them already 25 years old, in support of an aquatic,
or at least littoral, ancestry for Homo and conclude that Man probably first
learnt to swim when he was ‘no bigger than an otter’. Recent research on
alternative explanations for the supposed aquatic features of hominids receives
hardly a mention.

Crawford and Marsh also dismiss the great apes and Neanderthals as aberrant
forms whose deviant terrestrial habits led inevitably to their extinction:
‘The primates that did (become arboreal) became degenerates.’ Next we have
a whirlwind tour of the environmental destruction wrought by human hunting
and agriculture during the last million years. The longest stop is in Bronze
Age Crete with comments from Aristotle and the biologist Cyril Darlington.

The book ends with a lengthy tirade attributing heart disease, senility,
metal retardation, dental decay and many other human woes to refined foods,
the modern practices of animal husbandry and colonialism. Most scientists
would agree with the main contentions: bad diets promote disease. Although
modern diets have eliminated many diseases such as scurvy and rickets, caused
by specific deficiencies in the diet, they may have increased the incidence
of others, such as heart disease and dental caries.

For their own health and that of their children, people should be encouraged
to avoid harmful foods. But the basic message is obscured by the rambling,
emotional style and dark warnings about an apocalypse: ‘The brain and nervous
system will be the next to go . . . unless something is done.’ However,
there is little realistic advice on how ‘something’ might be achieved. The
authors seem to be advocating a return to a littoral paradise, somewhere
between a Gauguin painting and those sunlit seaside holidays of childhood
(but without the icecream and chocolate), where lush plants and placid animals
abound and wholesome food is gathered by the basketful.

It is difficult to determine why or for whom this book was written.
It provides no significant new information that would be of interest to
biologists, the writing style is speculative, theoretical and in many places
so imprecise as to be misleading, for example, ‘replication of an amino-acid
four letter code in DNA’. The thesis is unconvincing. It lurches from extreme
simplification to references to obscure organisms and biochemical processes
that would be unintelligible to a non-biologist.

To illustrate their propositions, the authors rely heavily upon anecdotes
related to them by their friends which leads them to sweeping statements
and invalid generalisations. They use taxonomic terms imprecisely: ‘mammals’
are referred to as a family, ‘carnivores’ generally seem to mean felids
or canids. It certainly does not mean Carnivora, which include several partially
or entirely herbivorous species, notably the giant panda, or carnivorous
organisms, most of which are invertebrates or fishes. In their frequent
references to ‘herbivores’, the authors seem to be thinking mainly of bovids
and equids; they give scant attention to the more abundant groups of herbivorous
vertebrates, such as rodents, lagomorphs, grazing and seed-eating birds
or even to camelids, suids and proboscideans, and none to insects or gastropods,
in spite of the fact that these invertebrates are responsible for more than
half of all terrestrial herbivory.

Crawford and Marsh quote Darwin’s writings frequently but some of the
conclusions drawn from them verge on the farcical. For example, his account
of the tactics used by aboriginals in Tasmania (where there are no large
native mammals) to evade European armies is quoted in support of the proposition
that upright posture is irrelevant to hunting of African ungulates by early
hominids.

Darwin’s strength was his breadth and depth of knowledge of a wide variety
of topics from improvement of crops and domestic livestock to island biogeography.
He weighed each source of information and line of reasoning, integrating
them to develop a theory that explained a wide range of features of many
different organisms. His theory has proved to be consistent with many of
the evolutionary processes discovered since his time. Most alternative theories
of evolution, including this one, place undue emphasis on a few topics and
fail to address large areas of biological knowledge. A few anecdotes and
some wishful thinking do not make a convincing theory.

Caroline Pond writes courses on biology for the Open University and
Dick Colby teaches cell biology and environmental chemistry at Stockton
State College, New Jersey