Animal Coloration, or in full Animal Coloration: An Account of the Principal Facts and Theories Relating to the Colours and Markings of Animals, is a book by the English zoologist Frank Evers Beddard, published by Swan Sonnenschein in 1892. It formed part of the ongoing debate amongst zoologists about the relevance of Charles Darwin's theory of natural selection to the observed appearance, structure, and behaviour of animals, and vice versa.

Beddard states in the book that it contains little that is new, intending instead to give a clear overview of the subject. The main topics covered are camouflage, then called 'protective coloration'; mimicry; and sexual selection. Arguments for and against these aspects of animal coloration are intensively discussed in the book.

The book was reviewed in 1892 by the major journals including The Auk, Nature, and Science. The scientist reviewers Joel Asaph Allen, Edward Bagnall Poulton and Robert Wilson Shufeldt took up different positions on the book and accordingly praised or criticized Beddard's work.

Modern evaluation of the book is from a variety of perspectives, including the history of Darwinism, the history of the Thayer debate on the purpose of camouflage, the mechanisms of camouflage, sexual selection, and mimicry. Beddard is seen as having covered a wide swath of modern biology with both theory and experiment.

Context

Beddard (1858–1925) was an English zoologist specializing in Annelid worms, but writing much more widely on topics including mammals and zoogeography. He also contributed articles on earthworms, leeches and nematode worms to the 1911 Encyclopædia Britannica. His decision to write an accessible book on animal coloration falls into this pattern. Beddard wrote Animal Coloration at a time when scientists' confidence in Charles Darwin's theory of evolution by natural selectionDarwin, 1859. was at a low ebb. Beddard's bookBeddard, 1892. was part of an ongoing debate among zoologists about how far natural selection affected animals, and how far other forces – such as the direct action of light – might be the causes of observed features such as the colours of animals. Edward Bagnall Poulton's far more strongly pro-Darwinian book The Colours of Animals had appeared just two years earlier in 1890.Poulton, 1890.

Approach

Beddard explains in his preface that the book grew from his 1890 Davis Lectures given for the public at London Zoo. The book "contains hardly anything novel, but professes to give some account of the principal phenomena of coloration exhibited by animals."Beddard, 1892. p. iii. He also notes that since Poulton's recent book "deal[s] with colour almost entirely from the point of view of natural selection, I have attempted to lay some stress upon other aspects of the question." Similarly, because Poulton treated insects in some detail, Beddard chooses to give more attention to other groups, though "it is impossible not to devote a good deal of space to insects".Beddard, 1892. p. iv. The examples are mainly from Beddard's own observation of "animals that may be usually seen in the Zoological Society's Gardens", though he also introduces and quotes the work of other scientists, including Henry Walter Bates and Alfred Russel Wallace.

Illustrations

The book has four colour plates by Peter Smit, who both drew and prepared the chromolithographic plates. Plate 1 is stated in the List of Illustrations "To face page 108", but as bound in the first edition it is used as a Frontispiece, facing the title page.

There are also 36 woodcuts (in black and white) in the text, though one of these, "Eolis and Dendronotus" is intentionally repeated as figures 10 and 19 to accompany the text in two places. The woodcuts vary from small line drawings on a simple white background (as in the diagrammatic figure 28 of Psyche helix, and figure 34 of the winter moth) to page-width illustrations like figure 2 which shows ermines in winter pelage, in a realistic depiction with a detailed snowy scene in the background. The woodcuts are certainly by a number of different artists; many are unsigned, but figures 5 and 26 are signed "E.A. Brockhaus X.A" lower right (X=cut, A=Artist), while figure 29 is signed "GM" lower left, and figures 35 and 36 are signed "ES" lower left. Figure 2 bears a monograph "FR", lower left, and figure 7, of the penguin Aptenodytes patagonica is stated to be "from Brehm" (Brehms Tierleben).

Structure

Animal Coloration has a simple structure of six chapters in its 288 pages.

1. Introductory

Beddard distinguishes colour, when an animal has just one, from coloration, when there is some kind of pattern of two or more colours. He discusses the mechanisms of colour production, both structural coloration and pigments, and the reasons for coloration, including the red of haemoglobin used to carry oxygen. Non-adaptive coloration is considered, and a section argues that "the action of natural selection in producing colour changes must be strictly limited".

2. Coloration affected by the environment

In this chapter Beddard continues to explore the possible direct effect of the environment, i.e. with "no possible relation to natural selection".Beddard, 1892. p. 42. The effects of different foods, temperature and humidity are discussed. Beddard argues against Poulton's view that natural selection has removed the pigment from cave-dwelling animals, agreeing rather with Wallace that pigment is produced as a by-product. Beddard grants that the change to white of arctic animals in winter looks like natural selection, rather than a direct effect of the environment, but argues that some animals do not change, including the musk ox which he describes as "comparatively defenceless".

3. Protective coloration

"Protection" is a shorthand in Beddard's vocabulary for camouflage necessitated by natural selection, whether of prey for defence against predators hunting by sight, or of predators concealing themselves for attack on watchful prey. He mentions that Wallace includes the green of tree-frequenting animals and the tawny of desert animals under "General Protective Resemblance", and mentions his own experiments which agree with Poulton's observation that lizards "do pass over and leave unnoticed protectively coloured caterpillars".Beddard, 1892. p. 92. However, Beddard continually tests the validity of this explanation:

He observes that "Every naturalist traveller appears to have some instance to relate of how he was taken in by a protectively-coloured insect. These stories are told with a curiously exaggerated delight at the deception...", giving as example how Professor Drummond in his book Tropical Africa thought a mantid was a wisp of hay. He picks up on the casually mentioned fact that Drummond's African companion was not deceived, writing that we should not judge camouflage "from the human standpoint".Beddard, 1892. pp. 109-110.

On the other hand, Beddard writes that people who had only seen the giraffe, zebra, and jaguar in the zoo would think them "among the most conspicuously coloured of the Mammalia", but that seen "in their native countries" they are "most difficult to detect".Beddard, 1892. p. 85.

The chapter ends with a discussion of animals that can change colour, including fish like the sole, the chameleon, the horned lizards and the tree frogs including the European species Hyla arborea. He cites Poulton's suggestion that the tree frog's camouflage may be both defensive (protecting from predators) and aggressive (facilitating the hunting of insects).Beddard, 1892. pp. 140-147.

4. Warning coloration

In this chapter Beddard discusses the warning coloration (aposematism) of animals, which he notes "have a precisely opposite tendency" to camouflage, "viz., to render their possessor conspicuous". He at once says that the explanation was "first devised by Mr. Wallace" for insects. The chapter therefore begins with the insects, often using English species as examples. He examines critically whether eye-like markings and other warnings actually work. He discusses experiments by Poulton on the elephant hawk-moth, where a sand lizard is only briefly startled,Beddard, 1892. p. 152. and his own at the London zoo using a range of predators and different insects.Beddard, 1892. pp. 153-156. Beddard is only partially convinced, flirting with Dr. Eisig's theory that the pigments creating the colours of caterpillars are inherently distasteful, and hence that "the brilliant colours (i.e. the abundant secretion of pigment) have caused the inedibility of the species, rather than that the inedibility has necessitated the production of bright colours as an advertisement." So Beddard suggests that "the advent of bird-life proved a disastrous event for these animals, and compelled them to undergo various modifications", except when they were already by luck warning coloured and distasteful.Beddard, 1892. p. 173.

5. Protective mimicry

This chapter discusses Batesian mimicry, also mentioning observations and opinions of Fritz Müller and Wallace. Beddard grants that Bates's theory is very strongly supported by the observations that Bates made in South America, especially on butterflies, though again he tests the evolutionary explanation in different cases. He cites Wallace's rules of mimicry, such as that the imitators are always the more defenceless, and always less numerous, than their models,Beddard, 1892. p. 206. as covering all the examples he has given. However, he then states various objections, including that "the Danaidae, themselves an uneatable race of butterflies and models for mimicry, resemble in South America the uneatable Heliconiidae". He points out that this does not meet any of Wallace's rules so it is "not a case of true mimicry", but is "supposed rather to be like that which is seen between various other unpalatable animals". Müllerian mimicry is not mentioned explicitly in the book, though Beddard does write that this example "tends to the advantage of the insects, for their enemies have to learn fewer colours and patterns, and thus are less likely to make mistakes, than if the lesson to be learnt were an excessively complicated one."Beddard, 1892. pp. 212-213.

By the end, Beddard concludes that "Nevertheless, cases of mimicry that do occur—particularly among Lepidoptera—are often so striking that no other explanation ... seems to account for the finishing touches, at least, of the resemblance". He remains sceptical of cases "which are to be appreciated only by insects", as he considers that insects might not have good enough vision for mimicry to work.Beddard, 1892. p. 252.

6. Sexual coloration

The final chapter begins with examples of sexual dimorphism, such as "the antlers of the stag, the spurs of the cock... and the gorgeous plumes found in the males of the birds of paradise", with other examples chosen from across the animal kingdom. Darwin's theory of sexual selection is explained; Beddard then states the objection that female birds must be supposed to have "a highly-developed aesthetic sense" to choose between similar-looking males, and worse, that females of closely related species must have "immense[ly]" different tastes. He concludes, though, that the question cannot be answered by what we consider improbable, but requires "actual observation".Beddard, 1892. pp. 265-266. He calls Poulton's arguments for sexual selection "very ingenious", but writes that Wallace's two different (non-selective) explanations "might both be accepted". He concludes that "it is quite possible that sexual selection may have played a subordinate part" in producing sexually dimorphic coloration.Beddard, 1892. p. 282.

Reception

Contemporary

The Auk