My attention was first called to this Cetacean genus while residing with my
brother in the Royal Botanical Gardens, Calcutta. The residence1 of the Superintendent
of these Gardens, from its proximity to the river hank, and from its commanding
position, overlooking a long deep reach of the Hughli, afforded very favourable conditions
for observing the habits and for obtaining specimens of this dolphin.
The observations there instituted led me to doubt the conclusion which Eschricht had
arrived at, viz., that the animal actually leaves the river during the cold weather
and takes to the sea, and I therefore commenced a correspondence to render my
inquiries complete, and also drew up a series of questions to elicit all the facts
regarding its distribution and habits. This schedule of queries was printed and
circulated by Government among the civil and other officials resident along the
courses of the greater rivers of India and Burma, and among the members of the
Pilot Service. Notwithstanding that the inquiry was of a novel and rather
unusual character, the replies were most complete and full of interest, and, moreover,
examples of the dolphin were sent to me from the Indus, Ganges, and
Brahmaputra.
I gladly embrace this opportunity to express my indebtedness to all of those
officers whose hearty co-operation in the research has greatly enabled me to settle
the questions which are treated of in this contribution towards a history of this
Cetacean. The following remarks on distribution are the result of a careful analysis
of the reports received.
Distribution.—To illustrate the distribution of this Cetacean genus I have had
the accompanying map prepared, in which its range is shown by a coloured line
carried through those river systems of India in which it exists, and a glance will
show that the information I have received does not establish its presence in the
Nerbudda or Godavery, nor in the river systems of Burma.
The pilots stationed at the Sandheads, and who having so frequently to pass up
and down the Hughli in which the dolphin abounds, are therefore familiar with it,
unite with other Government Marine officials thoroughly acquainted with the sea-face
of the delta of Bengal, in asserting that the long-snouted dolphin of the Ganges is
never seen out at sea. I have never heard of an instance of its occurrence below
Mud Point in Saugor Island, at the mouth of the Hughli, and from the reports
submitted to me it would appear to have a similar limit to its seaward distribution in
the other estuary streams of the'Ganges and Brahmaputra, and I have satisfied myself
of the correctness of these observations by personally going round a considerable
portion of the sea-face of the Sunderbunds. Similar reports have reached me regarding
the restriction of this genus to the fresh waters of the Indus. I have also to
add the testimony of Blyth* that it has never been observed out to sea.
Its distribution in the Ganges is recorded over an area comprised between the
77th and 89th degrees of east longitude. In the Brahmaputra it occurs through-
1 Roxburgh, who, with Lebeck, shares the credit o f having first described and named the dolphin of the Ganges,
designed the house and lived in it.
£ Journ. As. Soc., Bengal, vol. xxviii, 1859, p. 493.
out all the main river, as far eastwards as longitude 95° by latitude 27 30 north,
frequenting also all its larger streams. In the Indus it is found all the year round,
from latitude 24° to latitude 34° north, being also distributed through the Jhelum,
Chenab, Ravi, and Sutlej rivers up to their exits from the hills; the area over which
it ranges in that part of India being included between the 68th and 77th degrees of
longitude. I t has thus a permanent distribution in these river systems over 12 of
latitude and 27° of longitude; or, in other words, it has 800 miles of a northerly distribution
from its lowest point of range, 22° latitude, as it occurs in the Ganges,
with 1,880 miles of lateral extension.
The upward range of this dolphin is apparently only limited by insufficiency of
water, and by rocky barriers. As pointed out by Wallich, Hardwick’s specimen was
obtained 1,000 milan above Calcutta, and Cuvier remarks that it ascends the Ganges
in great numbers as'high as the river is navigable. Even in the month of Ma-y>
when the Ganges is very low, it extends up the Jumna as far as Delhi, and also enters
for a short way all the larger affluents of the main stream. In the Brahmaputra, at
the same season of the year, it is found throughout the river Sas- far north-east as
Dibrugarh, and it probably extends beyond that point, for it is permanently present
in such rivers as-the Dihing, Dhansiri, Dikhu, and Disang. Erom the patrol of
Kalabagh on the Indus, it is reported to be constantly present, which is also its
habit in the Ravi and in the Sutlej, but it is said to have been found in the Indus,
in April, as high up as Attock. The reports, however, all unite in confirming the
natural anticipation that it has its widest range in the height of the rains, when the
rivers are in flood, and that its distribution is most limited in the hot months when
the rivers are low.
According to my own observations it is more frequently seen in the Hughli at
Calcutta, and such distances from the sea in the cold weather, than during the height
of summer and the rains, and this coincides with what was observed by Blyth and
Cantor; but the latter conjectured that it migrated to the ocean at other seasons than in
the cold weather. As I have stated, however, all the evidence negatives this conjecture.
During the hot months I have rarely observed it in the Hughli, which it appears
almost wholly to desert at that period. Its presence, however, as already stated,
lias been reported to me during all the year, but it is exceedingly rare from May
to the end of June, so that it is to a certain extent migratory. The fishermen say
that with the approach of the hot weather the dolphin ascends the river, returning
with the rains. In July, and up to the end of September, its existence is demonstrated
by its being frequently caught in the nets of the fishermen, but were it
not for its capture, its presence could not then be determined. Living, as I have
done, for three years overlooking the river, I have never observed a dolphin rise
during the rains, although I have watched most carefully for them, and all the fishermen
I have conversed with on the subject have told me that they never see them
rise at that season. This fact may be accounted for on the supposition that the
strength of the current is so great when the Hughli is full that the dolphin is
prevented from rising to the surface in the marked manner it does during the