In the Virginian deer the young are likewise spotted, and about five
per cent. of the adult animals living in Judge Caton s park, as I am
informed by him, temporarily exhibit at the period when the red summer
coat is being replaced by the bluish winter coat, a row of spots on
each flank, which are always the same in number, though very variable
in distinctness. From this condition there is but a very small step to
the complete absence of spots in the adults at all seasons; and,
lastly, to their absence at all ages and seasons, as occurs with
certain species. From the existence of this perfect series, and more
especially from the fawns of so many species being spotted, we may
conclude that the now living members of the deer family are the
descendants of some ancient species which, like the axis deer, was
spotted at all ages and seasons. A still more ancient progenitor
probably somewhat resembled the Hyomoschus aquaticus for this animal is
spotted, and the hornless males have large exserted canine teeth, of
which some few true deer still retain rudiments. Hyomoschus, also,
offers one of those interesting cases of a form linking together two
groups, for it is intermediate in certain osteological characters
between the pachyderms and ruminants, which were formerly thought to be
quite distinct. (42. Falconer and Cautley, Proc. Geolog. Soc. 1843;
and Falconer s Pal. Memoirs, vol. i. p. 196.)
A curious difficulty here arises. If we admit that coloured spots and
stripes were first acquired as ornaments, how comes it that so many
existing deer, the descendants of an aboriginally spotted animal, and
all the species of pigs and tapirs, the descendants of an aboriginally
striped animal, have lost in their adult state their former ornaments?
I cannot satisfactorily answer this question. We may feel almost sure
that the spots and stripes disappeared at or near maturity in the
progenitors of our existing species, so that they were still retained
by the young; and, owing to the law of inheritance at corresponding
ages, were transmitted to the young of all succeeding generations. It
may have been a great advantage to the lion and puma, from the open
nature of their usual haunts, to have lost their stripes, and to have
been thus rendered less conspicuous to their prey; and if the
successive variations, by which this end was gained, occurred rather
late in life, the young would have retained their stripes, as is now
the case. As to deer, pigs, and tapirs, Fritz Muller has suggested to
me that these animals, by the removal of their spots or stripes through
natural selection, would have been less easily seen by their enemies;
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