Until recently there has been a paucity of museum material. While this has been largely overcome for the eastern Atlantic form and some is being collected in Canada of the western Atlantic seals, practically nothing is yet available from the Baltic. In any case no one has yet brought what material there is together for comparison. When this is done it is quite likely that sufficient difference will be found to warrant the recognition of 3 sub-species. The geographical isolation, which is normally required for such a recognition, appears to be complete and biologically reinforced. The Baltic grey seals occur in the Baltic itself and in the Gulf of Finland, but do not penetrate westward into the Bornholm area or the Kattegat. The eastern Atlantic seals occur from the west coast of Brittany, all round the British Isles and on the Norwegian coast, but few records exist of their appearance as adults on the Dutch coast or Frisian shores. Grey seals are certainly present in the Faeroes and Iceland region and it is thought that these are eastern Atlantic from their autumnal breeding season, but it is a far cry from Iceland to the western Atlantic breeding grounds off Nova Scotia.
In Canada the Arctic Unit has for a number of years been investigating both common and grey seals. While some of their results parallel our observations for the eastern Atlantic, others tend to emphasise the differences. Dr Mansfield and his collaborators have of course an interest in several other species of arctic seals but for our two species contact is maintained with British workers.
For the Baltic grey seal the story is not so satisfactory. Mr Oliver Hook has for a number of years been into the Baltic to track down the pups and to relate the ice movements with the probable centres of breeding. So far, however, except for willing co-operation in his work, the Swedes have not undertaken much research on their own. Political difficulties are probably the cause since further investigation of breeding areas and so on would almost certainly involve Finnish and Soviet coastal waters. There seems, however, some urgency for work in the Baltic since the indications are that the population is decreasing considerably. In an enclosed sea this could lead to near extermination, unless international co-operation is established and this is difficult in the absence of facts.
The species has a number of characteristics not normally taken into account by systematists which emphasise its uniqueness. All the other members of the Phocinae are either much more aquatic in their normal behaviour, or are confined to colder waters and associated with ice, or both. In British waters Halichoerus grypus is a truly temperate seal and always breeds on land. Both physical and behavioural (or ecological) characteristics tend to show that Halichoerus grypus diverged from the main Phocine stock early on. Its habit of breeding on land with the establishment of a social system may thus have evolved quite separately and does not indicate connecting links with other Pinnipede species in the Otariidae.
For many years the grey seal of Britain was thought to be the bearded seal, Erignathus barbatus, and it was not until 1825 that it was firmly established that it was Halichoerus grypus. This may appear to the layman as either merely a matter of words or else plainly stupid. But there is some excuse for this confusion. Normally when a species is named and described its name and description are tied to a specimen which is located in a museum, and any more specimens which might belong to that species can be compared with it. Unfortunately this is not the case with most species of seal and there has been an enormous amount of confusion, because everything depended on a verbal description. Consequently although it could confidently be asserted that Halichoerus grypus existed (it could easily be seen in the Baltic) and that Erignathus barbatus was clearly different and occurred, widespread, in the north Atlantic, it was not known to which the grey seal of Britain belonged. The earlier descriptions of it were too vague, although several of the early workers thought they corresponded more nearly with those of the bearded seal. The really astounding thing was that there was such a paucity of material for comparison. Hundreds of grey seals were killed each year for blubber or hide, yet until very recently the British Museum (Natural History) had only one adult skull, and many international museums had none. No complete skeleton existed in any museum except the National Museum of Wales in Cardiff where that of a cow was mounted.* If the hard parts were not preserved then certainly the soft parts were not. No account of the general disposition of the viscera can be found in the literature and the information about most of the anatomy of soft parts contained in this book has been specially obtained by first-hand dissection.
An equal ignorance was displayed about the general behaviour and life-history of the animal. The principal account is given by Millais (1905) who collected together what previous writers had said and added a great many observations of his own. But all of this was anecdotal and largely based on occasional visits to rookeries lasting a few hours or at most a day or two. The basic difficulty was one of accessibility for, as we shall see, even the breeding sites are isolated and situated in some of the stormiest waters round the British Isles. When the seals are no longer on these rookeries they may be hauled-out on any of dozens of islets or skerries spread over many square miles of sea and can only be found by meticulous searching. We know now that these sites can alter with the seasons and may, to a lesser degree, alter from day to day depending on wind and tide or even, one feels, on the idiosyncrasies of the seals themselves. It is no wonder, therefore, that earlier workers found difficulties in establishing even the basic facts of the yearly cycles and life-histories of this seal, without the aid of modern means of transport.
The first serious attempt to come to grips with the problems posed by this species was made by F. Fraser Darling in the late 1930’s. He decided to live with the grey seals and nearly all subsequent workers have done the same. This involves some difficulties and dangers, for all the islands involved are uninhabited and some are without fresh water. Consequently all supplies and a form of habitation must be taken ashore to cover not only the intended stay but for a much longer period, since return to the mainland is entirely dependent on weather and an enforced stay of up to a week tacked on to a planned three weeks is not unusual. Darling began his studies in small rookeries where each individual could be recognised and the progress of its behaviour related from day to day. Only in this way could the correct succession or pattern of behaviour become firmly established. To plunge into a large rookery with hundreds or even thousands of individuals, more arriving and others departing, makes it impossible for the observer to understand what is happening unless prior experience has shown him the correct sequence of activities. Darling’s observations in the Treshnish and Summer Isles therefore prepared him for North Rona, and his accounts of the breeding season are remarkably accurate.
In a book published in 1936 (A Beast Book for the Pocket) some 27 statements are made concerning the biology of the grey seal. Of these 22 are wrong; not slightly wrong but completely and utterly so. Darling’s work altered all that for the autumnal period and for much of the summer.
After the second world war our knowledge increased rapidly. Mr J. L. Davies began in 1947 by investigating the breeding season in the comparatively small group found off the Pembrokeshire coast, notably on Ramsey Island. In two subsequent years, 1950–51 a small group from London led by Dr L. Harrison Matthews